EP3649197A1

EP3649197A1 - Rigid and ductile polyamide-based transparent composition and use thereof

Info

Publication number: EP3649197A1
Application number: EP18762569.4A
Authority: EP
Inventors: Mathieu SABARD; Benoît BRULE; Benjamin Saillard; Regis Cipriani
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2017-07-07
Filing date: 2018-07-06
Publication date: 2020-05-13
Also published as: KR20200026963A; CN110869444A; FR3068705A1; KR102562876B1; FR3068705B1; CN110869444B; JP2020526616A; US20200199360A1; US11396600B2; JP7464519B2; WO2019008288A1

Abstract

The invention relates to the use of at least one impact modifier having a refractive index IR1 in a polyamide matrix consisting of a mixture of amorphous polyamide and semicrystalline polyamide, said matrix having a refractive index IR2, the difference in absolute value of IR1 - IR2 not exceeding 0.006, to produce a transparent composition having a fatigue strength, under the fatigue test referred to as notched "Ross-Flex", greater than 50 000 at -10°C.

Description

Rigid and ductile transparent composition based on polyamide and its

use

The present invention relates to impact and transparent modified polyamide thermoplastic matrix compositions comprising at least one impact modifier whose difference in refractive index IRi with that of the polyamide matrix IR2 is less than or equal in absolute value to 0.006. It also relates to its use for extrusion, injection or thermoforming, in particular for the manufacture of articles obtained by extrusion, injection, in particular for the manufacture of sports shoes, especially ski or running shoes, or compression molding.

The invention also relates to a method of manufacturing said sports articles and the articles obtained by said method.

Sporting goods manufacturers face a number of challenges.

The articles must evolve towards more lightness in order to reduce as much as possible the energy spent during their use.

They must also allow the athlete to obtain the sensations necessary for the control of the movements and to transmit quickly the muscular impulses.

The rigidity of a piece is directly related to the elastic modulus of the constituent material of this piece and to the cube of the thickness of the walls.

A high module material makes it possible to reduce the thickness of the pieces thus to gain a lot on the weight of these while keeping the rigidity necessary for a good elastic return essential for the sportsman.

In many sports articles, it is also necessary to guarantee good resistance to impact (cold shock on a ski boot for example) and also good resistance to repeated solicitations (folding the sole of a football boot eg epaulettes, elbow pads, knee pads or shin guards).

The international application WO 2015/150662 describes mixtures of polyamide and PEBA in which the PEBA is used as impact modifier, in particular a mixture PA1 1 and PEBA PA 1 1 / PTMG 1000 (50/50), having a compromise of rigidity, of shock and resistance to alternating flexion and having an optimized fluidity for the injection of component of sporting goods (soles, ski boot hulls, rigid shoes with crampons ...).

It is specified in this application that the addition of impact modifiers such as polyolefins, in particular grafted, in particular by maleic anhydride, make it possible to improve the impact level of the polyamides but increase the viscosity in a very significant manner in parallel. in the molten state which makes the product difficult to inject especially to make fine parts.

Articles, especially ski boots must also have thermoforming properties so as to fit the shoe, especially the tip of the shoe, to the foot.

They must also have good properties in fatigue resistance (Ross Flex).

The international application WO 2014/037647 discloses a transparent composition comprising a copolyamide of the following general formula A XY, the X unit representing an alicyclic diamine unit, said composition being used for the manufacture of a transparent molded article, such as a sole of shoe or shoe insole element, in particular of a sports shoe.

The international application WO 09/153534 describes in particular a composition comprising an amorphous polyamide, a semi-crystalline polyamide and an elastomer for the manufacture of various objects such as spectacle frames, lenses or spectacle lenses, electrical equipment, electronic or automotive, surgical equipment, packaging or sporting goods.

US application 201 1 105697 discloses a transparent molding composition comprising an amorphous polyamide, a semi-crystalline polyamide and an elastomer in a proportion of 0 to 10% for the manufacture of transparent articles for the manufacture of sports articles.

EP 1227131 discloses a transparent composition comprising an amorphous polyamide, a semi-crystalline polyamide and a flexible modifier for ski top decoration.

However, none of these compositions makes it possible to obtain a compromise between room temperature rigidity, low temperature ductility, fatigue resistance and transparency. The object of the present invention is therefore to provide compositions that overcome the various drawbacks of the prior art above and to obtain a compromise between rigidity at ambient temperature, ductility at low temperature, fatigue resistance while presenting transparency properties and good behavior during the implementation, in particular by injection.

Another subject of the invention relates to the use of said transparent composition for extrusion, injection or thermoforming, in particular for the manufacture of articles obtained by extrusion, injection, in particular for the manufacture of sports shoes. including ski or running shoes, or compression molding.

Yet another object relates to a method of manufacturing said sports articles and articles obtained by said method.

The present invention therefore relates to the use of at least one impact modifier having a refractive index IRi in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, said matrix having an IR2 refractive index, the difference in absolute value IR1 - IR2 being less than or equal to 0.006,

for forming a transparent composition exhibiting a notched "Ross Flex" fatigue test resistance greater than 50,000 at -10 ° C.

In other words, the present invention therefore relates to the use of a composition comprising at least one impact modifier having a refractive index IR1 in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, said matrix having a refractive index IR2, the difference in absolute value IR1-IR2 being less than or equal to 0.006,

The Applicant has thus surprisingly discovered that the use of an impact modifier with a polyamide matrix whose difference in refractive index in absolute value does not exceed 0.006 allowed the constitution of a transparent composition having a compromise of rigidity. , shock and resistance to alternating flexing, especially for extrusion, for the injection of sports articles and also having thermoforming properties. The term "transparent", as used, means that the composition has a transparency such that the transmittance at 560 nm on a 2 mm thick plate is greater than or equal to 75% determined according to ISO 13468-2: 2006 .

The refractive index IRi is measured with an Abbe refractometer according to the ISO489 standard.

The refractive index IR2 is calculated from the refractive indices of each constituent polyamide of the matrix according to the following formula:

(% semi-crystalline polyamide x IR semi-crystalline polyamide +% amorphous polyamide x IR amorphous polyamide),

and said refractive indices of each polyamide constituting the matrix (IR of the semicrystalline polyamide and IR of the amorphous polyamide) having themselves been measured with an Abbe refractometer according to the ISO489 standard.

The notched "Flex Flex" fatigue test is conducted in accordance with ASTM D1052 09 (2014) (except that the sample is notched and unbored and the bend angle is 60 °). Pieces 2 mm in thickness, 150 mm in length and 20 mm in width were made from compositions of the invention (I _n ) or comparative compositions (C _n ). These pieces were notched in V (1 × 1 mm width and depth, with a notch bottom radius of 0.25 mm) and then conditioned for 7 days at 70 ° C. under 62% relative humidity. The number of cycles is 100 / min

Advantageously, the notched "Flex Flex" fatigue test resistance is greater than 100,000 at 23 ° C.

Advantageously, said composition is free of polyether block amide (PEBA). In this embodiment, the PEBAs are therefore excluded from the shock modifiers.

An amorphous polyamide, within the meaning of the invention, denotes an amorphous transparent polyamide having only a glass transition temperature (no melting point (Tf)), or a very slightly crystalline polyamide having a glass transition temperature and a point of melting such that the enthalpy of crystallization during the step of cooling at a speed of 20K / min in Differential Scanning Calorimetry (DSC) measured according to the standard ISO 1,1357-3: 2013 is less than 30 J / g, especially less than 20 J / g, preferably less than 15 J / g. The transition temperature vitreous (Tg) measured by DSC at a heating rate of 20K / min according to the standard ISO 1,1357-1: 2009 and ISO 1,1357-2: 2013 for these polyamides is greater than 75 ° C.

A semicrystalline polyamide, within the meaning of the invention, denotes a polyamide which has a melting point (Tf) in DSC according to the standard ISO 1,1357-3: 2013, and an enthalpy of crystallization during the cooling step at a speed of 20K / min in DSC measured according to the ISO 1,1357-3 standard of 2013 greater than 30 J / g, preferably greater than 40 J / g.

Advantageously, the present invention relates to the use of a composition comprising at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semicrystalline polyamide, defined above, in which said mixture comprises, in weight, the total being equal to 100%:

55 to 75% by weight, preferably 60 to 72% of at least one semicrystalline polyamide whose average number of carbon atoms relative to the nitrogen atom is greater than 9, said semi-crystalline polyamide being of formula AZ in which,

A is an aliphatic repeating unit chosen from a unit obtained from the polycondensation of at least one amino acid and a unit obtained from the polycondensation of at least one lactam or an X.Y unit obtained from the polycondensation:

at least one diamine, said diamine being chosen from a linear or branched aliphatic diamine, a cycloaliphatic diamine and an aromatic diamine or a mixture thereof, and

at least one dicarboxylic acid, said diacid being chosen from: an aliphatic diacid, a cycloaliphatic diacid and an aromatic diacid,

said diamine and said diacid comprising from 4 to 36 carbon atoms, preferably from 6 to 18 carbon atoms, and

Z represents an aliphatic repeating unit as defined for A but different from A and is from 0 to 20% relative to the sum A + Z;

25 to 45% by weight, preferably 28 to 40% of an amorphous polyamide.

said mixture optionally comprising a polyamide oligomer. By "polyamide oligomer" is meant an oligomer of number average molecular weight less than that of the semi-crystalline polyamide, in particular said oligomer having a number average molecular weight of from 1000 to 15000 g / mol, in particular of 1000 at 10,000 g / mol, from 1000 to 5000 g / mol. Advantageously, the proportion by weight of oligomer relative to the total weight of the composition is from 0 to 10%, especially from 3 to 7%.

Advantageously, when the oligomer is present, it replaces the semicrystalline polyamide.

The oligomer may be chosen from oligomers of linear or branched aliphatic polyamides, oligomers of cycloaliphatic polyamides, oligomers of semi-aromatic polyamides, oligomers of aromatic polyamides, linear or branched aliphatic polyamides, cycloaliphatic and semi-aromatic polyamides. and aromatic having the same definition as above.

The oligomer is therefore derived from condensation:

at least one lactam, or

at least one amino acid, or

at least one diamine with at least one dicarboxylic acid, or

a mixture of these.

The oligomer can not therefore correspond to the condensation of a diamine with a lactam or an amino acid.

The oligomer may also be a copolyamide oligomer or a mixture of oligomers of polyamides and copolyamide.

For example, the oligomer is monofunctional Nh, monofunctional CO2H or difunctional CO2H or NH2.

The prepolymer may therefore be mono or difunctional, acidic or amine, that is to say it has only one terminal function amino or acid, when it is monofunctional (in this case the other end is non-functional, in particular CH3), or two amino terminal functions or two acid terminal functions, when it is difunctional.

Advantageously, the oligomer is an aliphatic oligomer, in particular it consists of PA1 1.

Advantageously, the oligomer is monofunctional, preferably NH 2 or CO2H, preferably mono NH 2. It can also be non-functional at both endings, including diCH3. Obtaining monofunctional oligomers NH2 can be carried out by reacting a (linear or branched) alkyl or monocarboxylic acid aryl after condensation of a lactam or of an amino acid or of a diamine with a dicarboxylic acid.

The diH2 oligomer can be obtained by reaction of a diamine after condensation of a lactam or of an amino acid or of a diamine with a dicarboxylic acid.

Obtaining monofunctional oligomers CO2H can be carried out by reaction of an alkyl (linear or branched) or aryl monocarboxylic acid after condensation of a lactam or an amino acid or a diamine with a dicarboxylic acid.

Obtaining diCO2H oligomers can be carried out by reacting a dicarboxylic acid after condensation of a lactam or an amino acid or a diamine with a dicarboxylic acid.

Obtaining non-functional diCH3 oligomers may be effected by reacting the amine endings of the oligomer with a monocarboxylic acid alkyl and amino terminal amino acid termini.

The Mn can be determined by calculation from the rate of terminal functions determined by potentiometric titration in solution and the functionality of said olygomers.

Mn masses can also be determined by size exclusion chromatography or by NMR.

Advantageously, said mixture comprises from 60 to 70% of at least one semicrystalline polyamide as defined above and from 30 to 40% of an amorphous polyamide as defined above.

Throughout the description, all percentages are by weight.

Throughout the description, the boundaries of the ranges of values presented are included.

The term "polyamide" used in the present description covers both homopolyamides and copolyamides.

advantageously,

Semi-crystalline polyamide:

Whether Z is present or not, the polyamide of formula AZ must be semi-crystalline as defined above. With regard to constituent A:

The average number of carbon atoms relative to the nitrogen atom is greater than 9.

Advantageously, it is greater than 10.

In the case of a PA-X.Y type homopolyamide, the number of carbon atoms per nitrogen atom is the average of the X unit and the Y unit.

In the case of a copolyamide, the carbon number per nitrogen is calculated according to the same principle. The calculation is carried out using the molar prorata of the different amide units. A: aliphatic repeating pattern

In a first variant of the invention, the aliphatic repeating unit A is obtained from the polycondensation of an aminocarboxylic acid.

Advantageously, said aminocarboxylic acid comprises from 9 to 12 carbon atoms. It may thus be chosen from 9-aminononanoic acid (denoted 9), 10-aminodecanoic acid (denoted 10), 11-aminoundecanoic acid (denoted 1 1) and 12-aminododecanoic acid (denoted 12). ), advantageously the aminocarboxylic acid is 11-aminoundecanoic acid.

In a second variant of the invention, the aliphatic repeating unit A is obtained from the polycondensation of a lactam.

Advantageously, the lactam comprises from 9 to 12 carbon atoms. It can thus be chosen from decanolactam (denoted 10), undecanolactam (denoted 1 1) and laurolactam or lauryllactam (denoted 12), advantageously the lactam is lauryllactam.

More preferably, the repeating unit A is obtained from a single aminocarboxylic acid or a single lactam.

However, it is entirely possible to use, to obtain this same unit A, a mixture of two or more aminocarboxylic acids, a mixture of two or more lactams, but also a mixture of one, of two or more aminocarboxylic acids with one, two or more lactams. A: X.Y repeating pattern

The repeating unit XY is a unit obtained from the polycondensation of at least one linear or branched aliphatic diamine or a mixture of two or several of these, or at least one cycloaliphatic diamine or at least one aromatic diamine, or a mixture thereof,

and at least one dicarboxylic acid selected from an aliphatic diacid, a cycloaliphatic diacid and an aromatic diacid.

The molar proportions of diamine and of dicarboxylic acid are preferably stoichiometric.

The diamine and the dicarboxylic acid each comprise from 4 to 36 carbon atoms and advantageously from 6 to 18 carbon atoms.

The aliphatic diamine used to obtain this repeating unit X.Y is an aliphatic diamine which has a linear main chain comprising at least 4 carbon atoms.

This linear main chain may, where appropriate, include one or more methyl and / or ethyl substituents; in this latter configuration, it is called "branched aliphatic diamine". In the case where the main chain has no substituent, the aliphatic diamine is called "linear aliphatic diamine".

Whether or not it comprises methyl and / or ethyl substituents on the main chain, the aliphatic diamine used for obtaining this repeating unit XY comprises from 4 to 36 carbon atoms, advantageously from 4 to 18 carbon atoms, advantageously from 6 to 18 carbon atoms, advantageously from 6 to 14 carbon atoms.

When this diamine is a linear aliphatic diamine, it then corresponds to the formula HN Ch Jx-Nh and can be chosen for example from butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, hexadecanediamine, octadecanedia-mine and octadecenediamine. The linear aliphatic diamines which have just been mentioned can all be bio-resourced within the meaning of the ASTM D6866 standard.

When this diamine is a branched aliphatic diamine, it may especially be 2-methylpentanediamine, 2-methyl-1,8-octanediamine or trimethylene (2,2,4 or 2,4,4) hexanediamine.

When the diamine is a cycloaliphatic diamine, it is chosen for example from bis (3,5-dialkyl-4-aminocyclohexyl) -methane, bis (3,5-dialkyl-4-aminocyclohexyl) ethane, bis (3, 5-dialkyl-4-aminocyclohexyl) propane, bis (3,5- dialkyl-4-aminocyclohexyl) -butane, bis (3-methyl-4-anninocyclohexyl) -nnethane or 3'-dimethyl-4,4'-diannino-dicyclohexyl-nnethane commonly known as "BMACM" or "MACM" (and noted B below), p-bis (aminocyclohexyl) -methane commonly known as "PACM" (and noted hereinafter P), risopropylidènedi (cyclohexylamine) commonly referred to as "PACP", isophorone diamine (denoted IPD hereinafter) and 2,6-bis (amino methyl) norbornane commonly referred to as "BAMN", 1,3-bis (aminomethyl) cyclohexyl (1,3 BAC), 1,4-bis (aminomethyl) cyclohexyl ( 1, 4 BAC) and a mixture thereof,.

A non-exhaustive list of these cycloaliphatic diamines is given in the "Cycloaliphatic Amines" publication (Encyclopaedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pp. 386-405).

The aromatic diamine may be selected from 1,3-xylylene diamine and 1,4-xylylenediamine.

The dicarboxylic acid may be chosen from linear or branched aliphatic carboxylic diacids, cycloaliphatic dicarboxylic acids and aromatic dicarboxylic acids.

The dicarboxylic acid may be chosen from linear or branched aliphatic carboxylic diacids.

When the dicarboxylic acid is aliphatic and linear, it can be chosen from succinic acid (4), pentanedioic acid (5), adipic acid (6), heptanedioic acid (7), acid octanedioic acid (8), azelaic acid (9), sebacic acid (10), undecanedioic acid (1 1), dodecanedioic acid (12), brassylic acid (13), tetradecanedioic acid (14), hexadecanedioic acid (16), octadecanedioic acid (18), octadecenedioic acid (18), eicosanedioic acid (20), docosanedioic acid (22) and fatty acid dimers containing 36 carbons. The fatty acid dimers mentioned above are dimerized fatty acids obtained by oligomerization or polymerization of unsaturated monobasic fatty acids with a long hydrocarbon chain (such as linoleic acid and oleic acid), as described in particular in the document EP 0 471 566.

When the dicarboxylic acid is cycloaliphatic, it may comprise the following carbon skeletons: norbornyl methane, cyclohexane, cyclohexylmethane, dicyclohexylmethane, dicyclohexylpropane, di (methylcyclohexyl) or di (methylcyclohexyl) propane. When the dicarboxylic acid is aromatic, it may be chosen from terephthalic acid (denoted T), isophthalic acid (denoted I) and a naphthalenic acid.

Advantageously, said semi-crystalline polyamide is of formula AZ in which A is a repeating unit obtained from the polycondensation of at least one XY unit obtained from the polycondensation of at least one linear or branched aliphatic diamine and from at least one aliphatic dicarboxylic acid.

Advantageously, said semi-crystalline polyamide is of formula AZ in which A is a repeating unit obtained from the polycondensation of an XY unit obtained from the polycondensation of a linear or branched aliphatic diamine and of an aliphatic dicarboxylic acid .

Z: another aliphatic repeating pattern

Z denotes another repeating unit and may correspond to an aliphatic repeating unit or an X.Y unit as defined above for A, provided that it is different from A.

The proportion of Z present is from 0 to 20% by weight relative to the sum A + Z, in particular from 0.1 to 20%.

Amorphous polyamide:

The amorphous polyamide may be a homopolyamide or a copolyamide. The amorphous polyamides are chosen from aliphatic, cycloaliphatic and aromatic polyamides or a mixture thereof.

In particular, the amorphous polyamide (or when the composition comprises a mixture of amorphous polyamides, at least one of the amorphous polyamides, or even each of the amorphous polyamides) comprises at least one unit corresponding to the diamine formula of C.sub.1 -C.sub.11 -diacid.

The C.sub.1 -C.sub.18 diacid diamine repeating unit is a unit obtained from the polycondensation of at least one linear or branched aliphatic diamine, or at least one cycloaliphatic diamine or at least one aromatic diamine or one mixing two or more of these and at least one aliphatic dicarboxylic acid or at least one cycloaliphatic dicarboxylic acid or at least one aromatic dicarboxylic acid.

The molar proportions of diamine and of dicarboxylic acid are preferably stoichiometric. The diamine and the dicarboxylic acid each comprise from 4 to 36 carbon atoms and advantageously from 6 to 18 carbon atoms.

The aliphatic diamine used to obtain this repeating diamine unit of Cb-Ca-acid is as defined above for the diamine of component A.

The cycloaliphatic diamine may be chosen for example from bis (3,5-dialkyl-4-aminocyclohexyl) -methane, bis (3,5-dialkyl-4-aminocyclohexyl) ethane, bis (3,5-dialkyl) -4 aminocyclohexyl) propane, bis (3,5-dialkyl-4-aminocyclohexyl) butane, bis (3-methyl-4-aminocyclohexyl) methane or 3'-dimethyl-4,4'-diamino dicyclohexyl methane commonly known as "BMACM" or "MACM" (and denoted B below), p-bis (aminocyclohexyl) methane commonly known as "PACM" (and noted hereinafter P), risopropylidènedi (cyclohexylamine) commonly referred to as "PACP", isophorone diamine (denoted IPD below) and 2,6-bis (amino methyl) norbornane commonly referred to as "BAMN".

When the dicarboxylic acid is aliphatic and linear, it is as defined above for the diacid Y.

When the dicarboxylic acid is cycloaliphatic, it may comprise the following carbon skeletons: norbornyl methane, cyclohexane, cyclohexylmethane, dicyclohexylmethane, dicyclohexylpropane, di (methylcyclohexyl) or di (methylcyclohexyl) propane.

When the dicarboxylic acid is aromatic, it may be chosen from terephthalic acid (denoted T), isophthalic acid (denoted I) and a naphthalenic acid.

In one embodiment, said blend comprises 60 to 70% semi-crystalline polyamide and 30 to 40% amorphous polyamide. Answering to the impact modifier

The impact modifier can be any impact modifier from the moment when the difference in its refractive index with that of the polyamide matrix in absolute value does not exceed 0.006. The impact modifier is advantageously constituted by a polymer having a flexural modulus of less than 100 MPa measured according to the ISO 178 standard and Tg of less than 0 ° C. (measured according to the standard 1 1357-2 at the point of inflection of the DSC thermogram), in particular a polyolefin.

In one embodiment, PEBAs are excluded from the definition of shock modifiers.

The impact modifier polyolefin may be functionalized or non-functionalized or be a mixture of at least one functionalized and / or at least one non-functionalized. For simplicity, the polyolefin has been designated by (B) and functionalized polyolefins (B1) and non-functionalized polyolefins (B2) have been described below.

A non-functionalized polyolefin (B2) is conventionally a homopolymer or copolymer of alpha olefins or diolefins, such as, for example, ethylene, propylene, butene-1, octene-1, butadiene. By way of example, mention may be made of:

Homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene or linear low density polyethylene), VLDPE (very low density polyethylene or very low density polyethylene) and metallocene polyethylene.

homopolymers or copolymers of propylene.

ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM).

styrene / ethylene-butene / styrene block copolymers (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS).

copolymers of ethylene with at least one product chosen from unsaturated carboxylic acid salts or esters, such as alkyl (meth) acrylate (for example methyl acrylate), or vinyl esters of carboxylic acids Saturated such as vinyl acetate (EVA), the proportion of comonomer up to 40% by weight.

The functionalized polyolefin (B1) may be a polymer of alpha olefins having reactive units (functionalities); such reactive units are acid, anhydride or epoxy functions. By way of example, mention may be made of the preceding polyolefins (B2) grafted or copolymerized with unsaturated epoxides such as glycidyl (meth) acrylate, or with carboxylic acids or the corresponding salts or esters such as (meth) acrylic acid (which may be totally or partially neutralized with metals such as Zn, etc.) or with anhydrides of carboxylic acids such as maleic anhydride. A functionalized polyolefin is, for example, a PE / EPR mixture, the weight ratio of which can vary widely, for example between 40/60 and 90/10, said mixture being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate of, for example, 0.01 to 5% by weight,

The functionalized polyolefin (B1) may be chosen from the following (co) polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the degree of grafting is, for example, from 0.01 to 5% by weight:

PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing, for example, from 35 to 80% by weight of ethylene;

ethylene-vinyl acetate copolymers (EVA), containing up to 40% by weight of vinyl acetate;

ethylene and alkyl (meth) acrylate copolymers containing up to 40% by weight of alkyl (meth) acrylate;

ethylene and vinyl acetate (EVA) and alkyl (meth) acrylate copolymers containing up to 40% by weight of comonomers.

The functionalized polyolefin (B1) may also be chosen from ethylene / propylene predominantly propylene copolymers grafted with maleic anhydride and then condensed with monoamino polyamide (or a polyamide oligomer) (products described in EP-A-0342066). .

The functionalized polyolefin (B1) may also be a co- or terpolymer of at least the following units: (1) ethylene, (2) (meth) acrylate or vinyl ester saturated carboxylic acid and (3) anhydride such as maleic anhydride or (meth) acrylic acid or epoxy such as glycidyl (meth) acrylate.

By way of example of functionalized polyolefins of the latter type, mention may be made of the following copolymers, in which ethylene is preferably at least 60% by weight and in which the monomer ter (the function) represents, for example, from 0.1 to 10% by weight of the copolymer:

ethylene / alkyl (meth) acrylate / (meth) acrylic acid or maleic anhydride or glycidyl methacrylate copolymers;

ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymers;

ethylene / vinyl acetate or alkyl (meth) acrylate / (meth) acrylic acid or maleic anhydride or glycidyl methacrylate copolymers.

In the foregoing copolymers, the (meth) acrylic acid may be salified with Zn or Li.

The term "alkyl (meth) acrylate" in (B1) or (B2) refers to C1-C8 alkyl methacrylates and acrylates, and may be selected from methyl acrylate, ethyl acrylate, and the like. n-butyl acrylate, iso-butyl acrylate, ethyl-2-hexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

Moreover, the above-mentioned polyolefins (B1) can also be crosslinked by any suitable method or agent (diepoxy, diacid, peroxide, etc.); the term "functionalized polyolefin" also includes mixtures of the aforementioned polyolefins with a difunctional reagent such as diacid, dianhydride, diepoxy, etc. capable of reacting with them or mixtures of at least two functionalized polyolefins that can react with one another.

The copolymers mentioned above, (B1) and (B2), can be copolymerized randomly or sequentially and have a linear or branched structure.

The molecular weight, the MFI index, the density of these polyolefins can also vary to a large extent, which the skilled person will appreciate. MFI, abbreviation of Melt Flow Index, is the melt flow index. It is measured according to ASTM 1238. Advantageously, the non-functionalized polyolefins (B2) are chosen from homopolymers or copolymers of polypropylene and any homopolymer of ethylene or copolymer of ethylene and a comonomer of higher alpha olefinic type such as butene or hexene. octene or 4-methyl-1-pentene. We can cite, for example, PP, high density PE, medium density PE, linear low density PE, low density PE, very low density PE. These polyethylenes are known to those skilled in the art as being produced according to a "radical" process, according to a "Ziegler" type of catalysis or, more recently, according to a "metallocene" catalysis.

Advantageously, the functionalized polyolefins (B1) are chosen from any polymer comprising alpha olefinic units and units carrying polar reactive functional groups such as the epoxy, carboxylic acid or carboxylic acid anhydride functions. By way of examples of such polymers, mention may be made of ter polymers of ethylene, alkyl acrylate and maleic anhydride or of glycidyl methacrylate, such as the Lotader® of the Applicant or the polyolefins grafted with maleic anhydride such as Orevac® of the Applicant and ter polymers of ethylene, alkyl acrylate and (meth) acrylic acid. Mention may also be made of homopolymers or copolymers of polypropylene grafted with a carboxylic acid anhydride and then condensed with polyamides or monoamino oligomers of polyamide.

Advantageously, said transparent composition is devoid of core-shell particles or heart-shell core-shell polymers.

By heart-bark particle, it is necessary to understand a particle whose first layer forms the heart and the second or all the following layers form the respective barks.

The core-shell core-shell particle may be obtained by a multistep process comprising at least two steps. Such a method is described for example in US2009 / 0149600 or EP0722961. In one embodiment, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which said impact modifier represents from 5 to 30%, especially from 10% to 30%, in particular from 15 to 27% of the total weight of the transparent composition.

In one embodiment, said impact modifier represents from 17 to 27%, in particular from 20 to 27% of the total weight of the transparent composition.

In another embodiment, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, wherein said transparent composition comprises from 0 to 5%, in particular from 0.001 to 5%, of at least one additive chosen from stabilizers, dyes, plasticizers, optical brighteners, or a mixture thereof.

Asking for the additive:

The additive is selected from stabilizers, dyes, plasticizers, optical brighteners or a mixture thereof.

By way of example, the stabilizer may be a UV stabilizer, an organic stabilizer or, more generally, a combination of organic stabilizers, such as a phenol antioxidant (for example of the type of irganox® 245 or 1098 or 1010 of the company Ciba-BASF), a phosphite-type antioxidant (for example irgafos® 126 and irgafos® 168 from Ciba-BASF) and possibly even other stabilizers such as HALS, which means Hindered Amine Light Stabilizing or stabilizing hindered amine light (for example Tinuvin® 770 from Ciba-BASF), an anti-UV (for example Tinuvin® 312 from Ciba), a phosphorus stabilizer. It is also possible to use amine antioxidants such as Naugard® 445 from Crompton or else polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

This stabilizer may also be a mineral stabilizer, such as a copper stabilizer. By way of example of such mineral stabilizers, mention may be made of copper halides and acetates. Incidentally, one may consider other metals such as silver, but these are known to be less effective. These copper-based compounds are typically associated with alkali metal halides, particularly potassium.

By way of example, the plasticizers are chosen from benzene sulphonamide derivatives, such as n-butyl benzene sulphonamide (BBSA); ethyl toluene sulfonamide or N-cyclohexyl toluene sulfonamide; esters of hydroxy acids benzoic compounds, such as 2-ethylhexyl parahydroxybenzoate and decyl-2-hexyl parahydroxybenzoate; esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxytetrahydrofurfurylalcohol; and esters of citric acid or hydroxy-malonic acid, such as oligoethyleneoxy malonate.

It would not be outside the scope of the invention using a mixture of plasticizers.

For example, the optical brightener is uvitex OB BASF.

In one embodiment, said transparent composition comprises from 0 to 10% by weight of at least one fluidizing agent.

By fluidifying agent, it is necessary to understand a processing aid such as Bruggolen® TP-P1507 and calcium stearate for a process aid or demolding.

Advantageously, the present invention relates to the use of a composition comprising at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which said transparent composition comprises, by weight, the total being equal to 100%:

from 65 to 95% of said polyamide mixture, preferably from 73 to 85% by weight,

from 5 to 30% of at least one impact modifier, preferably from 15 to 27% by weight,

from 0 to 5%, in particular from 0.001 to 5% of at least one additive,

from 0 to 10% by weight of at least one fluidizing agent,

said amorphous polyamide being in sufficient proportion so that the composition is sufficiently ductile at low temperature, and rigid, and in particular has an impact resistance with a TDF <0 ° C as determined according to ISO 179 1 eA.

Advantageously, said composition has a flexural modulus greater than 850 MPa, especially greater than 870, in particular greater than or equal to 900 MPa, as determined according to the ISO 178: 2010 standard.

Advantageously, said composition has an impact resistance with a TDF <0 ° C as determined according to ISO 179 1 eA flexural modulus greater than 850 MPa, especially greater than 870, in particular greater than or equal to 900 MPa as determined according to ISO 178: 2010. The term "ductile" refers to the ability of a material to deform plastically without breaking.

Advantageously, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which the transparent composition of the invention is a thermoformable composition.

TDF is at the Ductile-Fragile transition temperature which corresponds to the temperature at which a material changes from a ductile behavior (partial breakage of the material) to a brittle behavior (complete rupture of the material). The ductile-brittle transition can therefore be seen as a temperature range where there is 50% brittle fracture (fragile behavior of the sample) and 50% partial failure (ductile behavior of the sample) and a competition between behavior ductile and fragile behavior.

The Charpy shock performed according to ISO 179 1 eA provides resilience.

The ductile-brittle transition (TDF) therefore corresponds to the inflection point of the resilience curve as a function of temperature.

In another embodiment, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which the transparent composition has a transparency such that the transmittance at 560 nm plate 2 mm thick is greater than 75% determined according to ISO 13468-2: 2006.

Advantageously, said transparent composition has a Haze less than or equal to 25% (in Haze unit), measured according to the ASTM D1003-97 standard.

In one embodiment, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semicrystalline polyamide, defined above, in which the semi-crystalline polyamide crystalline is an aliphatic polyamide.

Advantageously, said aliphatic semi-crystalline polyamide is chosen from

PA1 1, PA12, PA1010, PA1012, in particular PA1 1.

In one embodiment, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which the amorphous polyamide is a polyamide of formula A1 / X1Y1 in which:

- Al is an aliphatic repeating unit chosen from a unit obtained from the polycondensation of at least one aminocarboxylic acid, a unit obtained from the polycondensation of at least one lactam and a unit obtained from the polycondensation of at least one aliphatic diamine and at least one aliphatic diacid,

Xi is a cycloaliphatic diamine, and

Yi is a dicarboxylic acid, said diacid being chosen from an aliphatic diacid, a cycloaliphatic diacid and an aromatic diacid,

said diamine and said diacid comprising from 4 to 36 carbon atoms, preferably from 6 to 18 carbon atoms.

A repeating aliphatic unit is as defined above for A.

X 1 is as defined above for X being a cycloaliphatic diamine and Y 1 is as defined above for Y being a dicarboxylic acid.

Advantageously, said amorphous polyamide of formula A1 / X1Y1 used in the transparent composition is chosen from 1 1 / B10, 1 1 / P10, 12 / B10, 12 / P10, 11 / BI / BT, 11 / PI / PT, 12 / BI / BT, 12 / PI / PT, 11 / BI, 11 / PI, 12 / BI, 12 / PI, especially 11 / B10 or 11 / P10.

Advantageously, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which the semi-crystalline polyamide is a polyamide aliphatic and said amorphous polyamide is of formula A1 / X1Y1 in which A1 represents an aliphatic repeating unit chosen from a unit obtained from the polycondensation of an aminocarboxylic acid or a lactam as defined above, X1 is such that defined above for X being a cycloaliphatic diamine and Y1 is as defined above for Y being an aliphatic or aromatic dicarboxylic acid, in particular aliphatic.

In this embodiment, the semi-crystalline polyamide which is an aliphatic polyamide thus designates either a semicrystalline polyamide resulting from the polycondensation of an aminocarboxylic acid or a lactam as defined above, or an XY motif in which X represents a linear or branched aliphatic diamine, in particular linear and Y represents an aliphatic dicarboxylic acid. In this embodiment, the impact modifier is in particular a styrene / ethylene-butene / styrene block copolymer (SEBS).

Advantageously, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which said semi-crystalline aliphatic polyamide is PA1 1 and the amorphous polyamide is 1 1 / B10.

In one embodiment, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semicrystalline polyamide, defined above, in which the impact modifier is selected from styrene / ethylene-butene / styrene block copolymers (SEBS).

Advantageously, the present invention relates to the use of at least one impact modifier in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, defined above, in which the proportion of Z = 0.

Advantageously, said semi-crystalline polyamide and / or said amorphous polyamide of said transparent composition is (are) partially or totally bio-resourced (s).

According to another aspect, the present invention relates to a transparent composition comprising:

from 73 to 85% by weight of a polyamide matrix having an IR2 refractive index, as defined above,

from 15 to 27% by weight of at least one impact modifier having an IR1 refractive index,

from 0 to 5%, in particular from 0.001 to 5% by weight of at least one additive,

from 0 to 10% of at least one fluidifying agent,

the sum of the constituents being equal to 100% and the difference in absolute value IR1-IR2 being less than or equal to 0.006. Advantageously, the PEBA are excluded from the impact modifiers present in said composition defined above.

Advantageously, said polyamide matrix of said transparent composition is a mixture comprising from 55 to 75% by weight, preferably from 60 to 72% of an aliphatic semi-crystalline polyamide and from 25 to 45% by weight, preferably from 28 to 40% by weight. an amorphous polyamide.

Advantageously, said aliphatic semi-crystalline polyamide of said transparent composition is chosen from PA1 1, PA12, PA1010, PA1012, in particular PA1 1.

Advantageously, said amorphous polyamide of said transparent composition is selected from 1 1 / B10, 12 / B10, 1 1 / BI / BT, 1 1 / B1, in particular 1 1 / B10.

Advantageously, the aliphatic semi-crystalline polyamide of said transparent composition is PA1 1 and the amorphous polyamide is 1 1 / B10.

According to another aspect, the present invention relates to the use of a transparent composition as defined above, for the manufacture of sports articles or article eyewear or electrical and electronic article, obtained by extrusion, injection, molding or thermoforming .

In the latter case, the composition refers to that defined for the use of the impact modifier with the polyamide matrix and not only to the composition as such defined above.

According to one embodiment, the use of a transparent composition as defined above is for the manufacture of articles obtained by injection, in particular of a sports article, in particular a ski boot or a shoe part. a rigid shoe with a crampon or a portion of rigid shoes with a crampon, such as a football, rugby or football shoe, a hockey shoe or a portion of a hockey shoe, or a running shoe, a golf ball, golf or a golf ball game, lacrosse sport lacrosse or hockey article such as a helmet or sports equipment for the protection of the head, shoulders, elbows, hands, knees , back or shin, such as helmet, gloves, epaulettes, elbow pads, knee pads or shin guards. According to one embodiment, the use of a transparent composition as defined above is for the manufacture of articles obtained by injection such as optical articles, in particular glasses or a mask, in particular glasses or a mask used in the practice of a sport such as goggles or a ski mask.

According to one embodiment, the use of a transparent composition as defined above for the manufacture of articles obtained by extrusion such as films.

According to another aspect, the present invention relates to the use of a transparent composition as defined above, for thermoforming an article, in particular a portion of a ski or roller shoe or a hockey shoe, in particular a ski boot. or glasses or a mask, especially glasses or a sports mask, in particular goggles or a ski mask.

According to another aspect, the present invention relates to a process for preparing a transparent composition as defined above, comprising a step of mixing said matrix, said impact modifier, optionally said additive and optionally said fluidizing agent, with melted state, in particular in an extruder, at a temperature of between 230 and 330 ° C., in order to obtain, after granules, granules which will subsequently be injected at a temperature of between 230 and 330 ° C., on an injection molding machine for get the desired items.

As above, this method refers to the composition defined for the use of the impact modifier with the polyamide matrix and not only to the composition as defined above.

According to another aspect, the present invention relates to a shaped article, such as fiber, fabric, film, sheet, ring, injected piece tube, comprising the composition as defined above, which may be in the form of a mixture dry or after compounding on an extruder.

In the same way, the article refers to the composition defined for the use of the impact modifier with the polyamide matrix and not only to the composition as such defined above.

Advantageously, said article is characterized in that it consists of a sports article, in particular a ski boot or a part of a ski boot. or a rigid shoe with a crampon or a portion of rigid crampon shoes, such as a football, rugby or football shoe, a hockey shoe or a portion of a hockey shoe, or a running shoe, a golf ball or a golf ball game, or lacrosse sport lacrosse or a hockey article such as a helmet or sports equipment for the protection of the head, shoulders, elbows, hands, knees, back or shin, such as helmet, gloves, epaulets, elbow pads, knee pads or shin guards.

Advantageously, said article is characterized in that it consists of an optical article, in particular glasses or a mask, in particular glasses or a mask used in the practice of a sport such as protective glasses or a ski mask.

The invention will now be illustrated by the following examples without being limited to them.

EXAMPLES

The semi-crystalline polyamides (PAsc) and amorphous polyamides (PA am) are prepared by polycondensation according to the methods known to those skilled in the art.

The mixtures were implemented by a compounding process, thanks to a co-rotating twin-screw extruder of length 40 × (D = screw diameter and = 18 mm), at a flow rate Q = 7 kg / h, at a speed of screw 300 rpm, and at T = 270 ° C.

Ross Flex

% modifier 100 x Transmittance

Haze Modulus Number of cycles at the

ref Shock (PAsc / ΣPA) @ 560nm, TDF (° C) IR1-IR2

(2 mm) (%) Flexion (MPa) rupture at 23 ^o C / -10 ^o C

(Kraton ^® 1901) (%) 2mm (%)

- Notched -

Cl 7.5 50 83 - 1300 5 13 000/5 000 0.0045

C2 4 62 85 - 1250 23 7 000/3 000 0.0053

C3 10 50 83 - 1200 <0 8 000/3 000 0.0045

11 10 70 75 - 1140 <0> 100 000 /> 50 000 0.0059

C4 10 78 71 - 1050 <0> 100,000 /> 50,000 0.0065

C5 12.5 34 82 - 1200 <0 7000/4 000 0.0034

C6 12.5 50 84 - 1150 <0 8000/3 000 0.0045

C8 15 18 83 - 1180 <0 5 000/2 000 0.0023

C9 15 50 82 - 1110 <0 30 000/10 000 0.0045

12 15 63 79 - 1000 <0> 100 000 /> 50 000 0.0054

C10 15 82 69 - 980 <0> 100,000 /> 50,000 0.0067

13 17.5 63 78 - 960 <0> 100 000 /> 50 000 0.0054

Cil 20 35 83 - 1110 <0 12 000/2 500 0.0034

14 20 66 77 - 940 <0> 100 000 /> 50 000 0.0056

15

C12 100 <75 - 850> 0> 100000 /> 50000> 0.006

(Peba 40ShD)

12

C13 (Fusabond 55 <75 - 1100 <0> 100000 /> 50000> 0.006

493N)

21

C14 (Fusabond 67 <75 - 940 <0> 100000 /> 50000> 0.006

493N)

15 20 66 76 22 950 <0> 100000 /> 50000 0.0056

16 21 67 75 20 920 <0> 100000 /> 50000 0.0057

17 25 62 75 17 910 <0> 100000 /> 50000 0.0053

C15 0 30 88 - 1300> 0 3000/1000 -

C16 0 70 83 - 1200> 0 30000/12000 -

18 21 67.5 77 20 960 <0> 100000 /> 50000 0.0057

19 21 67.5 75 21 880 <0> 100000 /> 50000 0.0057

110 25 64 75 19 910 <0> 100000 /> 50000 0.0055

111 25 66 75 20 900 <0> 100000 /> 50000 0.0056

112 25 68 75 21 890 <0> 100000 /> 50000 0.0058

113 22.5 64 76 18 930 <0> 100000 /> 50000 0.0055

114 22.5 66 76 19 930 <0> 100000 /> 50000 0.0056

115 22.5 68 75 24 920 <0> 100000 /> 50000 0.0058

The flexural modulus is determined according to ISO 178: 2010

The Charpy shock is made according to the ISO 1791eA standard and allows to obtain the resilience.

The "Ross Flex" fatigue test is performed in accordance with ASTM D1052 09 (2014) with the modifications described above. Pieces 2 mm thick, 150 mm in length and 20 mm in width were made from compositions of the invention (I _n ) or comparative compositions (C _n ). These pieces were notched in V (1 x 1 mm width and depth, with a 0.25 mm notch bottom radius), the bending angle was 60 °, and then conditioned for 7 days at 70 ° C. at 62% relative humidity. The number of cycles is 100 / min.

Samples are tested at 23 ° C or -10 ° C.

By this so-called "Ross Flex" test, the number of times at which the piece, folded at the height of the notch at 60 ° and at a temperature of 23 ° C. or -10 ° C., is determined breaks. It is considered that the part fulfills the conditions of this test when the number of cycles is greater than or equal to 50000.

The results of the Ross Flex are expressed in numbers of cycles at break.

- means untested

The transmittance is determined according to ISO 13468-2: 2006.

Haze is measured according to ASTM D1003-97.

The impact modifier used is Kraton® FG 1901 (Kraton Polymers International) which is a maleic anhydride grafted SEBS except for composition C12 in which a PEBA (1 1 PTMG1000 (50/50)) of 40 Shore D is used, and the compositions C13 and C14 in which a Fusabond 493N (marketed by DuPont) which is a maleic anhydride modified ethylene copolymer.

The sum of the percent impact modifier and semicrystalline polyamide blend with the amorphous polyamide is 100% in all the examples except for Examples 19 which corresponds to 18 plus 2% by weight of Bruggolen® TP-P1507, the total being equal to 100% and for Examples 110-12 in which there is 6% PA1 1 -mono NH ₂ oligomer of Mn = 3000 g / mol, the total being equal to 100% and Examples 13-115 in which there is 4.5% PA1 1 -mono Nh oligomer of Mn = 3000 g / mol, the total being equal to 100%.

The polyamide mixture in the compositions of the invention consists of PAsc: PA1 1 and PAam: PA1 1 / B10

ΣPA =% PAsc +% PAam.

Claims

Use of a composition comprising at least one impact modifier having a refractive index IR1 in a polyamide matrix consisting of a mixture of amorphous polyamide and semi-crystalline polyamide, said matrix having a refractive index IR2, the difference in absolute value IR1 - IR2 being less than or equal to 0.006,

Use according to claim 1, wherein said transparent composition also has a fatigue test resistance greater than 100,000 at 23 ° C.

Use according to claim 1 or 2, wherein said mixture comprises, by weight, the total being equal to 100%:

A is an aliphatic repeating unit chosen from a unit obtained from the polycondensation of at least one aminocarboxylic acid and a unit obtained from the polycondensation of at least one lactam or an X.Y unit obtained from the polycondensation:

said diamine and said diacid comprising from 4 to 36 carbon atoms, preferably from 6 to 18 carbon atoms,

and Z represents an aliphatic repeating unit as defined for A but different from A and is from 0 to 20% relative to the sum A + Z; 25 to 45% by weight, preferably 28 to 40% of an amorphous polyamide.

said mixture optionally comprising a polyamide oligomer,

4. Use according to one of claims 1 to 3, wherein said impact modifier represents from 5 to 30%, in particular from 15 to 27% of the total weight of the composition. 5. Use according to claim 3, wherein the proportion by weight of oligomer relative to the total weight of the composition is from 0 to 10%, especially from 3 to 7%.

6. Use according to claim 3 or 4, wherein the oligomer is an aliphatic oligomer, in particular it consists of PA1 1, preferably monofunctional, preferentially mono Nh.

7. Use according to one of claims 1 to 6, wherein said transparent composition comprises from 0 to 5%, in particular from 0.001 to 5%, of at least one additive chosen from stabilizers, dyes, plasticizers, optical brighteners or a mixture thereof.

8. Use according to one of claims 1 to 7, wherein said transparent composition comprises from 0 to 10% by weight of at least one fluidizing agent.

9. Use according to one of claims 1 to 8, wherein said transparent composition comprises, by weight, the total being equal to 100%:

from 65 to 95% of said polyamide mixture, in particular from 73 to 85%

from 5 to 30% of at least one impact modifier, in particular from 15 to 27%,

from 0 to 5%, in particular from 0.001 to 5% of at least one additive,

from 0 to 10% by weight of at least one fluidizing agent,

said amorphous polyamide being in sufficient proportion so that the transparent composition is sufficiently ductile at low temperature, and rigid, and presents in particular an impact resistance with a TDF <0 ° C as determined according to ISO 179 1 eA.

10. Use according to one of claims 1 to 9, wherein the transparent composition has a transparency such that the transmittance at 560 nm plate 2 mm thick is greater than or equal to 75% determined according to ISO 13468- 2: 2006.

1 1. Use according to one of claims 1 to 9, wherein the transparent composition has a Haze less than or equal to 25% (in Haze unit), measured according to ASTM D1003-97.

12. Use according to one of claims 1 to 10, wherein the semi-crystalline polyamide is an aliphatic polyamide.

13. Use according to claim 12, wherein the aliphatic semicrystalline polyamide is selected from PA1 1, PA12, PA1010, PA1012, in particular PA1 1.

14. Use according to one of claims 1 to 13, wherein the amorphous polyamide is a polyamide of formula A1 / X1Y1 in which:

Xi is a cycloaliphatic diamine, and

The use according to claim 14, wherein the amorphous polyamide is selected from 1 1 / B10, 1 1 / P10, 12 / B10, 12 / P10, 11 / BI / BT, 11 / PI / PT, 12 / BI / BT, 12 / PI / PT, 1 1 / BI, 1 1 / PI, 12 / BI, 12 / PI, especially 1 1 / B10 or 1 1 / P10, B being bis (3-methyl-4-aminocyclohexyl) methane and P bis (aminocyclohexyl) methane.

16. Use according to one of claims 1 to 15, wherein the aliphatic semi-crystalline polyamide is PA1 1 and the amorphous polyamide is 1 1 / B10, B being the bis-

(3-methyl-4-aminocyclohexyl) -methane.

17. Use according to one of claims 1 to 16, wherein the impact modifier is selected from styrene / ethylene-butene / styrene block copolymers (SEBS).

18. Use according to one of claims 3 to 17, wherein the proportion of Z = 0.

19. Use according to one of claims 1 to 18, characterized in that the semi-crystalline polyamide and / or the amorphous polyamide is (are) partially or completely bio-resourced (s).

20. Transparent composition comprising:

from 73 to 85% by weight of a polyamide matrix having a refractive index IR2, as defined in one of claims 1 to 19,

from 15 to 27% by weight of at least one impact modifier having a refractive index IR1, excluding PEBA,

from 0 to 10% of at least one fluidifying agent,

the sum of the constituents being equal to 100% and the difference in absolute value IR1 - IR2 being less than or equal to 0.006.

21. Transparent composition according to claim 20, wherein said matrix is a mixture comprising from 55 to 75% by weight, preferably from 60 to 72% of a semi-crystalline aliphatic polyamide and from 25 to 45% by weight, preferably from 28 to 40% of an amorphous polyamide.

22. Transparent composition according to claim 20 or 21, wherein the aliphatic semi-crystalline polyamide is selected from PA1 1, PA12, PA1010, PA1012, in particular PA1 1. 23. Transparent composition according to one of claims 20 to 22, wherein the amorphous polyamide is selected from 1 1 / B10, 12 / B10, 1 1 / BI / BT, 1 1 / BI, especially 1 1 / B10, B being bis- (3-methyl-4-aminocyclohexyl) -methane.

24. Transparent composition according to one of claims 20 to 23, wherein the aliphatic semi-crystalline polyamide is PA1 1 and the amorphous polyamide is 1 1 / B10,

B being bis- (3-methyl-4-aminocyclohexyl) -methane.

25. Use of a transparent composition as defined in one of claims 1 to 19, for the manufacture of sports articles or article eyewear or electrical and electronic article, obtained by extrusion, injection, molding or thermoforming.

26. Use of a transparent composition according to claim 25, for the manufacture of articles obtained by injection, in particular of a sports article, in particular a ski boot or a portion of a ski boot or a rigid shoe with a crampon. or a portion of rigid crampon shoes, such as a football, rugby or football shoe, a hockey shoe or a portion of a hockey shoe, or a running shoe, a golf ball or a golf ball portion , or a lacrosse sport lacrosse or a hockey article such as a helmet or sports articles for the protection of the head, shoulders, elbows, hands, knees, back or shin, such as that helmet, gloves, epaulets, elbow pads, knee pads or shin guards. 27. Use of a transparent composition according to claim 25, for the manufacture of articles obtained by injection such as optical articles, in particular glasses or a mask, in particular glasses or a mask used in the practice of the invention. a sport such as goggles or a ski mask.

28. Use of a transparent composition according to claim 26 for the manufacture of articles obtained by extrusion such as films. 29. Use of a transparent composition as defined in one of claims 1 to 19, for thermoforming an article, in particular a portion of a ski boot or roller or hockey shoe, in particular a ski boot, or goggles or mask, including goggles or a sports mask, especially goggles or ski goggles.

30. A process for preparing a transparent composition as defined in one of claims 1 to 19, comprising a step of mixing said matrix, said impact modifier, optionally said additive and optionally said fluidizing agent, in the molten state. , in particular in an extruder, at a temperature of between 230 and 330 ° C., in order to obtain, after pellets, granules which will subsequently be injected at a temperature of between 230 and 330 ° C., on an injection molding machine to obtain the desired items.

31. Shaped article, such as fiber, fabric, film, sheet, rod, injected part tube, comprising the composition as defined in one of claims 1 to 19, which may be in the form of a dry mixture or after a compounding on an extruder.

32. Article according to claim 31, characterized in that it consists of a sports article, in particular a ski boot or a portion of a ski boot or a rigid shoe with a crampon or a portion of rigid shoes with a crampon, such as football, rugby or football boots, a hockey shoe or a portion of a hockey shoe, or a running shoe, a golf ball or a golf ball portion, or a lacrosse sport lacrosse or a hockey article such as a helmet or sporting goods for the protection of the head, shoulders, elbows, hands, knees, back or shin, such as helmet, gloves, epaulettes, elbow pads, knee pads or shin protectors.

3. Article according to claim 31, characterized in that it consists of an optical article, in particular glasses or a mask, including glasses or a mask used in the practice of a sport such as glasses. protection or ski mask.