EP3983484A1 - Polyamide compositions having a high modulus and a low dielectric constant and use thereof - Google Patents

Abstract

The present invention relates to the use of a mixture of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin, the mixture of solid and hollow glass reinforcements comprising from 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular from 5 to 35% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, for the dry preparation at 23°C of a composition having a modulus at least equal to 8 GPa, in particular at least equal to 10 GPa, in particular at least equal to 11 GPa, and a dielectric constant Dk less than or equal to 3.5, in particular less than or equal to 3.3, in particular less than or equal to 3.2 as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, in particular at a frequency of at least 2 GHz, in particular at a frequency of at least 3 GHz, at 23°C, under 50% RH.

Description

DESCRIPTION

TITLE: POLYAMIDE COMPOSITIONS WITH HIGH MODULE AND LOW MODULE

DIELECTRIC CONSTANT AND THEIR USE

[Technical area]

The present invention relates to the use of a mixture of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin for the manufacture of compositions having a high modulus and a low dielectric constant, their manufacturing process as well as said compositions.

[Prior art]

The manufacturers of original equipment (OEM), in particular for electronics, for telecom applications or for the exchange of data, such as for an autonomous vehicle or for applications connected between them, are more and more interested by materials used in the protection or cladding of this equipment which have a low dielectric constant.

Indeed, the advantage of such an integrated material, for example, in the casing of a mobile phone is to guarantee the integrity of the signal in an antenna application to ensure complete and high speed signal transmission.

Furthermore, in the context of data exchanges, the dielectric constant must be as low as possible in order to have the fastest possible data exchange.

The main challenges for such applications are therefore to have the lowest dielectric properties while retaining a very rigid protective or covering material. However, to obtain a rigid protective or covering material, it is often necessary to use glass fibers which will give the material a higher modulus and therefore higher rigidity.

Nevertheless, it is known that the presence of standard glass fibers, for example in a telephone shell, which makes it possible to obtain good rigidity of said shell, also drastically increases the dielectric constant, and will therefore disturb the transmission of the cell phone. signal.

It is therefore necessary to have a material which has both rigidity and therefore high modulus properties while maintaining a low dielectric constant so as to ensure complete and high speed signal transmission or to have data exchange. as fast as possible.

The problem stated above has therefore been solved by the present invention which therefore relates to the use of a mixture of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin, said mix of solid and hollow glass reinforcements comprising 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular 5 to 35% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements ,

to prepare a composition having a modulus, dry at 23 ° C, at least equal to 8GPa, in particular at least equal to 10 GPa, in particular at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3, 5, in particular less than or equal to 3.3, in particular less than or equal to 3.2 as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, in particular at a frequency of at least 2 GHz, especially at a frequency of at least 3 GHz, at 23 ° C, under 50% RH.

In other words, the present invention relates to the use of a mixture of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin, said mixture of solid glass reinforcements and hollow comprising 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular 5 to 35% by weight of hollow glass beads relative to the total of solid glass reinforcements and hollow,

for at least maintaining the modulus and reducing the dielectric constant of a composition comprising said mixture with said alloy relative to a composition comprising said alloy and glass reinforcements devoid of solid glass reinforcement or said alloy and glass reinforcements devoid of of hollow glass reinforcement, said modulus, dry at 23 ° C, of said composition being at least equal to 8GPa, in particular at least equal to 10 GPa, in particular at least equal to llGPa, and said dielectric constant of said composition being less than or equal to 3.5, in particular less than or equal to 3.3, in particular less than or equal to 3.2 as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, in particular at a frequency of at least 2 GHz, in particular at a frequency of at least 3 GHz, at 23 ° C, under 50% RH.

In one embodiment, the composition of the invention is devoid of polyamide 6 and 66.

The inventors have therefore unexpectedly found that the association of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin, which in addition with a specific proportion of hollow glass beads per ratio to the total of the solid and hollow glass reinforcements allowed the preparation of a composition having both a high modulus at least equal to 8GPa, in particular at least equal to 10 GPa, in particular at least equal to llGPa, and a dielectric constant Dk low, less than or equal to 3.5, in particular less than or equal to 3.3, in particular less than or equal to 3.2, thus making it possible to have a rigid material capable of ensuring complete transmission of the signal and at high speed or to have the fastest possible data exchange. There are different moduli (for example tensile modulus, flexural modulus, etc.). If we consider the flexural modulus, it is always lower than the tensile modulus.

These modules can be impacted by temperature and by the humidity level contained in the sample.

In one embodiment, the modulus defined above corresponds to both the flexural modulus and the tensile modulus, the flexural modulus being measured according to the ISO 178: 2010 standard and the tensile modulus (or modulus of elasticity E) being measured according to ISO 527-1 and 2: 2012.

In another embodiment, the modulus defined above corresponds to the flexural modulus and is measured as above.

In another embodiment, the modulus defined above corresponds to the tensile modulus and is measured as above.

The dielectric constant is defined as the ratio between the permittivity e of the material considered and the permittivity of the vacuum. It is denoted k or Dk and is measured according to ASTM D-2520-13. It is therefore the relative permittivity.

It is measured under 50% relative humidity (RH) at 23 ° C. on a sample previously dried, in particular at 80 ° C. for 5 days.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a dry modulus at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus. In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to tensile modulus and flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus. In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus and the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a dry modulus at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus. In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the flexural modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus. In one embodiment, said composition has a dry modulus at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency of at least 1 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.5, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus. In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.3, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to 8GPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to lOGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

In one embodiment, said composition has a modulus, dry at 23 ° C, at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3.2, at a frequency up to 2.4 GHz, under 50% RH, said modulus corresponding to the tensile modulus.

Measuring the dielectric loss (tan delta or tan (5)) (or power factor (tan delta or tan (5)) makes it possible to determine the state of the insulation of the composition.

Advantageously, the dielectric loss (tan delta) of said composition is less than or equal to 0.01, as measured on a dry sample, at 23 ° C, under 50% RH, at a frequency of at least 1 GHz, in particularly a frequency up to 2.4 GHz, according to ASTM D-2520-13.

The sample is therefore dried beforehand, in particular at 80 ° C. for 5 days and then tested at 23 ° C., under 50% RH.

In one embodiment, said composition has a modulus, dry at 23 ° C and a dielectric constant Dk, as defined above in the different embodiments, and a dielectric loss (tan delta) less than or equal to 0 , 01, as measured at 23 ° C on a dry sample, at 23 ° C, under 50% RH, at the same frequency as said dielectric constant in said embodiment.

For solid and hollow glass reinforcements

Full glass reinforcements

Solid glass reinforcements correspond to a fibrous glass material whose structure is solid (as opposed to hollow) and which can have any shape as long as that shape is full.

These shapes can be circular or non-circular in section.

A shape with a circular section is defined as a shape having at any point of its circumference a distance equal to the center of the shape and therefore represents a perfect or almost perfect circle. Any glass shape that does not have this perfect or almost perfect circle is therefore defined as a shape with a flat section.

Examples of, but not limited to, a flat section shape are flat shapes e.g. elliptical, oval or cocoon shape, star shapes, flake shapes, cruciforms, polygon and a ring.

The solid glass forms can in particular be solid and short glass fibers which, preferably, have a length of between 2 and 13 mm, preferably of 3 to 8 mm before use of the compositions.

Solid fiberglass can be:

- Or with a circular section with a diameter of 4 μm and 25 μm, preferably 4 to 15 μm.

- either with a non-circular section with an L / D ratio (L representing the largest dimension of the cross section of the fiber and D the smallest dimension of the cross section of said fiber) ranging from 2 to 8, in particular 2 to 4. L and D can be measured by electron microscopy at

scanning (SEM).

Hollow glass reinforcements

The hollow glass reinforcements correspond to a fibrous glass material whose structure is hollow (as opposed to solid) and which can have, in the same way as for the solid glass reinforcement, any shape from the moment when this shape is hollow.

The hollow glass shapes can in particular be short, hollow glass fibers which preferably have a length of between 2 and 13 mm, preferably 3 to 8 mm, before the compositions are used.

By hollow glass fiber is meant glass fibers whose hollow (or hole or lumen) inside the fiber is not necessarily concentric with respect to the external diameter of said fiber.

Hollow fiberglass can be:

- Or with a circular section with an outside diameter of 7.5 to 75 μm, preferably 9 to 25 μm, more preferably 10 to 12 μm.

It is obvious that the diameter of the hollow (the term "hollow" can also be referred to as either hole or lumen) is not equal to the outside diameter of the hollow fiberglass.

Advantageously, the diameter of the hollow (or hole or lumen) represents from 10% to 80%, in particular from 60 to 80% of the outside diameter of the hollow fiber.

- either with a non-circular section with an L / D ratio (L representing the largest dimension of the cross section of the fiber and D the smallest dimension of the cross section of said fiber) comprised of 2 to 8, especially 2 to 4. L and D can be measured by electron microscopy at

scanning (SEM).

Said mixture of solid and hollow glass reinforcements comprises 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular 5 to 35% by weight of hollow glass beads relative to the total. in total solid and hollow glass reinforcements.

In one embodiment, said mixture of solid and hollow glass reinforcements comprises 10 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular 10 to 35% by weight of hollow glass. hollow glass balls in relation to the total of solid and hollow glass reinforcements.

In one embodiment, said mixture of solid and hollow glass reinforcements, in addition to the hollow glass balls, comprises solid glass fibers selected from circular section glass fibers, flat section glass fibers and a mixture of these.

In one embodiment, said mixture of solid and hollow glass reinforcements comprises 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular 5 to 35% by weight of hollow glass. hollow glass balls relative to the total of solid and hollow glass reinforcements, said hollow glass balls representing the totality of the proportion of hollow reinforcements.

In this last embodiment, said mixture of solid and hollow glass reinforcements, in addition to the hollow glass balls constituting all of the hollow reinforcements, comprises solid glass fibers chosen from glass fibers with a circular section, glass fibers with flat sections and a mixture of these.

Advantageously, said mixture of glass reinforcements consists of 50 to 95% by weight of solid glass fibers and of 5 to 50% by weight of hollow glass balls, in particular of 65 to 95% by weight of solid glass fibers and 5 to 35% by weight of hollow glass beads.

Advantageously, said mixture of glass reinforcements consists of 50 to 90% by weight of solid glass fibers and 10 to 50% by weight of hollow glass beads, in particular 65 to 90% by weight of solid glass fibers. and 10 to 35% by weight of hollow glass beads.

Advantageously, said solid fiberglass is a fiberglass with a non-circular cross section.

In one embodiment, the solid glass reinforcement is a glass fiber having a Dk> 5 at a frequency ranging from 1 MHz to 5 GHz and in particular a Dk> 5 and a Df <0.005 at a frequency of 1 GHz.

Advantageously, the solid glass reinforcement is a glass fiber with a non-circular cross section and has an elastic modulus of less than 76 GPa as measured according to ASTM C1557-03. As regards the alloy consisting of at least one polyamide and at least one polyolefin Advantageously, said alloy consists of at least one polyamide and at least one polyolefin, the polyamide / polyolefin weight ratio of which is included from 95/5 to 50/50.

Polyolefin:

The polyolefin of said composition may be a grafted (or functionalized) or ungrafted (or non-functionalized) polyolefin or a mixture thereof.

The graft polyolefin can be an alpha olefin polymer having reactive units (functionalities); such reactive units are acid, anhydride or epoxy functions. By way of example, mention may be made of the preceding ungrafted polyolefins but which are grafted or co- or ter polymerized with unsaturated epoxides such as glycidyl (meth) acrylate, or with carboxylic acids or the corresponding salts or esters such as as (meth) acrylic acid (which can be totally or partially neutralized by metals such as Zn, etc.) or alternatively by carboxylic acid anhydrides such as maleic anhydride.

Advantageously, the grafted polyolefin is chosen from esters of unsaturated carboxylic acids such as, for example, alkyl acrylates or alkyl methacrylates, preferably said alkyls having from 1 to 24 carbon atoms, examples of acrylate or alkyl methacrylate are especially methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate;

vinyl esters of saturated carboxylic acids such as, for example, vinyl acetate or propionate.

Advantageously, said grafted polyolefin defined above is based on polypropylene.

An ungrafted polyolefin is conventionally a homopolymer or copolymer of alpha olefins or diolefins, such as, for example, ethylene, propylene, butene-1, 1-pentene, 3-methyl-1-butene, 1-hexene. , 4-methyl-1-pentene, 3-methyl-1-pentene, octene-1, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1 -eicocene, 1-dococene, 1-tetracocene, 1-hexacocene, 1-octacocene and 1-triacontene, preferably propylene or ethylene or dienes such as for example butadiene which can be mixed with a

compatible and functional compatibilizer, for example a polyethylene mixed with a maleized Lotader ^® or a maleized polyethylene, isoprene or 1,4-hexadiene.

In particular, the alpha olefin homopolymer is chosen from low density polyethylenes (LDPE, low density polyethylene), high density polyethylenes (HDPE), linear low density polyethylenes (LLDPE, linear low density polyethylene), very low polyethylene density (VLDPE, very low density polyethylene)) and metallocene polyethylene; In particular, the copolymers of alpha olefins or of diolefins are chosen from ethylene / alpha olefin polymers such as ethylene-propylene, ethylene-butylene, ethylene-propylene-diene monomer, ethylene-octene, alone or as a mixture with a polyethylene (PE);

Advantageously, said ungrafted polyolefin defined above is based on polypropylene.

The polyolefin of the composition can also be crosslinked or uncrosslinked or be a mixture of at least one crosslinked and / or at least one noncrosslinked.

Cross-linked polyolefin

The polyolefin of said composition according to the invention can be an uncrosslinked polyolefin and / or a crosslinked polyolefin, said uncrosslinked polyolefin and / or a crosslinked being presented as a phase dispersed in the matrix formed by the polyamide (s). .

Said crosslinked polyolefin results from the reaction of two or at least two products having groups reactive with each other.

More particularly, when said polyolefin is a crosslinked polyolefin, it is obtained from at least one product (A) comprising an unsaturated epoxide and at least one product (B) comprising an unsaturated carboxylic acid anhydride.

Product (A) is advantageously a polymer comprising an unsaturated epoxide, this unsaturated epoxide being introduced into said polymer, either by grafting or by copolymerization.

The unsaturated epoxide can in particular be chosen from the following epoxides:

- aliphatic glycidyl esters and ethers such as allylglycidyl ether, vinylglycidyl ether, glycidyl maleate and itaconate, glycidyl acrylate and methacrylate, and

- alicyclic glycidyl esters and ethers such as 2-cyclohexene-l-glycidylether, cyclohexene-4,5-diglycidyl carboxylate, cyclohexene-4-glycidyl carboxylate, 5-norbornene-2-methyl-2-glycidyl carboxylate and endocis-bicyclo (2,2, 1) -5-heptene-2,3-diglycidyl dicarboxylate.

According to a first form, the product (A) is a polyolefin grafted with an unsaturated epoxide. The term “polyolefin” is understood to mean a homopolymer or copolymer comprising one or more olefin units such as ethylene, propylene, butene-1 units or any other alpha-olefin. As an example of a polyolefin, there may be mentioned:

- polyethylene and, in particular, low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE) and very low density polyethylene (VLDPE); polypropylene; ethylene / propylene copolymers; elastomeric polyolefins such as ethylene-propylene (EPR or EPM) or ethylene-propylene-diene monomer (EPDM); or else metallocene polyethylenes obtained by single-site catalysis; - styrene / ethylene-butene / styrene (SEBS) block copolymers; styrene / butadiene / styrene (SBS) block copolymers; styrene / isoprene / styrene block copolymers (SIS); or else styrene / ethylene-propylene / styrene block copolymers;

- Copolymers of ethylene and of at least one product chosen from salts of unsaturated carboxylic acids, esters of unsaturated carboxylic acids and vinyl esters of saturated carboxylic acids. The polyolefin can in particular be a copolymer of ethylene and of alkyl (meth) acrylate or a copolymer of ethylene and of vinyl acetate.

According to a second form, the product (A) is a copolymer of alpha-olefin and of an unsaturated epoxide and, advantageously, a copolymer of ethylene and of an unsaturated epoxide.

Advantageously, the amount of unsaturated epoxide can represent up to 15% by weight of the copolymer (A), the amount of ethylene for its part representing at least 50% by weight of the copolymer (A).

Mention may more particularly be made of copolymers of ethylene, of a vinyl ester of saturated carboxylic acid and of an unsaturated epoxide, as well as copolymers of ethylene, of a

alkyl (meth) acrylate and an unsaturated epoxide. Preferably, the alkyl of the (meth) acrylate comprises from 2 to 10 carbon atoms. Examples of alkyl acrylates or methacrylates which can be used are in particular methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate and methyl acrylate. 2-ethylhexyl.

According to an advantageous version of the invention, the product (A) is a copolymer of ethylene, of methyl acrylate and of glycidyl methacrylate or a copolymer of ethylene, of n-butyl acrylate and of glycidyl methacrylate . Use may in particular the product marketed by Arkema under the name LOTADER® ^® AX8900.

According to another form of the invention, the product (A) is a product having two epoxy functions, such as for example the diglycidyl ether of bisphenol A (DGEBA).

Product (B) is advantageously a polymer comprising an unsaturated carboxylic acid anhydride, this unsaturated carboxylic acid anhydride being introduced into said polymer, either by grafting or by copolymerization.

Examples of unsaturated dicarboxylic acid anhydrides which can be used as constituents of product (B) are in particular maleic anhydride, itaconic anhydride, citraconic anhydride and tetrahydrophthalic anhydride.

According to a first form, the product (B) is a polyolefin grafted with an unsaturated carboxylic acid anhydride. As seen above, a polyolefin is a homopolymer or copolymer comprising one or more olefin units such as ethylene, propylene, butene-1 or any other alpha-olefin units. This polyolefin can in particular be chosen from examples of polyolefins listed above for product (A), when the latter is a polyolefin grafted with an unsaturated epoxide.

According to a second form, the product (B) is a copolymer of alpha-olefin and of an unsaturated carboxylic acid anhydride and, advantageously, a copolymer of ethylene and of an unsaturated carboxylic acid anhydride. Advantageously, the amount of unsaturated carboxylic acid anhydride can represent up to 15% by weight of the copolymer (B), the amount of ethylene for its part representing at least 50% by weight of the copolymer (B).

Mention may more particularly be made of copolymers of ethylene, of a vinyl ester of saturated carboxylic acid and of an unsaturated carboxylic acid anhydride, as well as of copolymers of ethylene, of a (meth) acrylate. alkyl and an unsaturated carboxylic acid anhydride. Preferably, the alkyl of the (meth) acrylate comprises from 2 to 10 carbon atoms. The alkyl acrylate or methacrylate can be chosen from those mentioned above for the product (A).

According to an advantageous version of the invention, the product (B) is a copolymer of ethylene, of an alkyl (meth) acrylate and of an unsaturated carboxylic anhydride. Preferably, product (B) is a copolymer of ethylene, ethyl acrylate and maleic anhydride or a copolymer of ethylene, butyl acrylate and maleic anhydride. We can use the products

marketed by the company ARKEMA under the names LOTADER ^® 4700 and LOTADER ^® 3410. It would not be departing from the scope of the invention if part of the maleic anhydride of the product (B), according to the first and second forms which come from to be described, was partially hydrolyzed.

Advantageously, the weight contents of product (A) and of product (B), which are noted

[A] and [B] respectively, are such that the ratio [B] / [A] is between 3 and 14 and, advantageously, between 4 and 9.

In the composition according to the invention, the crosslinked polyolefin can also be obtained from products (A), (B) as described above and from at least one product (C), this product (C) comprising a unsaturated carboxylic acid or alpha-omega-aminocarboxylic acid.

Product (C) is advantageously a polymer comprising an unsaturated carboxylic acid or an alpha-omega-aminocarboxylic acid, one or the other of these acids being introduced into said polymer by copolymerization.

Examples of unsaturated carboxylic acids which can be used as constituents of product (C) are in particular acrylic acid, methacrylic acid, the carboxylic acid anhydrides mentioned above as constituents of product (B), these anhydrides being totally hydrolyzed.

Examples of alpha-omega-aminocarboxylic acids which can be used as constituents of product (C) are in particular 6-aminohexanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid. The product (C) can be a copolymer of alpha-olefin and of an unsaturated carboxylic acid and, advantageously, a copolymer of ethylene and of an unsaturated carboxylic acid. Mention may in particular be made of the fully hydrolyzed copolymers of product (B).

According to an advantageous version of the invention, the product (C) is a copolymer of ethylene and (meth) acrylic acid or a copolymer of ethylene, of an alkyl (meth) acrylate and of (meth) acrylic acid. The amount of (meth) acrylic acid can represent up to 10% by weight and, preferably, from 0.5 to 5% by weight of the copolymer (C). The amount of alkyl (meth) acrylate is generally between 5 and 40% by weight of the copolymer (C).

Advantageously, product (C) is a copolymer of ethylene, butyl acrylate and acrylic acid such as Escor ™ 5000 from ExxonMobil.

Preferably, the product (C) is a copolymer of ethylene, of butyl acrylate and of acrylic acid. Use may in particular the product marketed by BASF under the name LUCALENE ^® 3110.

The dispersed phase of crosslinked polyolefin can of course originate from the reaction of one or more products (A) with one or more products (B) and, where appropriate, with one or more products (C).

As already described in document WO 2011/015790, it is possible to use catalysts making it possible to accelerate the reaction between the reactive functions of products (A) and (B). Reference will therefore be made to the teaching of this document as regards examples of catalysts, the latter possibly being used in a weight content of between 0.1 and 3% and, advantageously, between 0.5 and 1% of the total weight of products (A), (B) and, if applicable, (C).

Advantageously, the weight contents of product (A), of product (B), of product (C) which are denoted respectively by [A], [B] and [C] are such that the ratio [B] / ([ A] + [C]) is between 1.5 and 8, the weight contents of products (A) and (B) being such that [C] <[A]

Advantageously, the [B] / ([A] + [C]) ratio is between 2 and 7.

Uncrosslinked polyolefin

The composition according to the invention can comprise at least one uncrosslinked polyolefin, said uncrosslinked polyolefin being presented as a phase dispersed in the matrix formed by the semi-crystalline polyamide (s).

The term “uncrosslinked polyolefin” means a homopolymer or copolymer comprising one or more olefin units such as ethylene, propylene, butene-1 units or any other alpha-olefin as defined above.

Advantageously, said composition comprises at least one crosslinked polyolefin as defined above and at least one uncrosslinked polyolefin as defined above. In one embodiment, said alloy consists of at least one polyamide and of a mixture of a grafted polyolefin based on polypropylene and an ungrafted polyolefin based on polypropylene.

Polyamide:

Said at least one polyamide is chosen from semi-crystalline polyamides, amorphous polyamides and a mixture thereof.

Advantageously, said at least one polyamide is chosen from a single amorphous polyamide, a semi-crystalline polyamide, and a mixture of two semi-crystalline polyamides.

A semi-crystalline polyamide, within the meaning of the invention, denotes a polyamide which exhibits a glass transition temperature in DSC according to standard ISO 11357-2: 2013 as well as a melting point (Tm) in DSC according to ISO standard 11357-3: 2013, and an enthalpy of crystallization during the cooling step at a speed of 20K / min in DSC measured according to standard ISO 11357-3 of 2013 greater than 30 J / g, preferably greater than 40 J / g.

An amorphous polyamide, within the meaning of the invention, denotes a polyamide exhibiting only a glass transition temperature (no melting point (Tm)) in DSC according to the ISO 11357-2: 2013 standard, or a very low crystalline polyamide having a glass transition temperature in DSC according to ISO 11357-2: 2013 and a melting point such as the enthalpy of crystallization during the cooling step at a speed of 20K / min in differential scanning calorimetry ("Differential Scanning Calorimetry »DSC) measured according to the ISO 11357-3: 2013 standard is less than 30 J / g, in particular less than 20 J / g, preferably less than 15 J / g.

The nomenclature used to define polyamides is described in standard ISO 1874-1: 2011 "Plastics - Polyamide materials (PA) for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is indeed known to those skilled in the art.

In a first variant, said alloy consists of a single polyamide which is an amorphous polyamide and of at least one polyolefin.

Amorphous polyamide:

Said amorphous polyamide can be a polyamide of formula A / XY, in which:

A is an aliphatic repeating unit obtained by polycondensation:

at least one C ₅ to Cis amino acid, preferably C ₆ to Cu, more preferably Cio to C12, or

at least one C ₅ to Cis lactam, preferably C ₆ to C12, more preferably Cio to C12, or of at least one C4-C36 aliphatic diamine Ca, preferably C6-C18, preferably C ₆ - C12, more preferably C10-C12, with at least one Cb C4-C36 dicarboxylic acid,

preferably C6-C18, preferably C6-C12, more preferably _C8-C12;

XY is an aliphatic repeating unit obtained by polycondensation:

of at least one cycloaliphatic diamine, or of at least one linear or branched aliphatic diamine X and

of at least one aromatic dicarboxylic acid or of at least one aliphatic dicarboxylic acid Y. Said amino acid may in particular be chosen from 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid as well as its derivatives, in particular N-heptyl-11-aminoundecanoic acid, in particular 11-aminoundecanoic acid.

Said lactam can in particular be chosen from pyrrolidinone, 2-piperidinone, caprolactam, enantholactam, caprylolactam, pelargolactam, decanolactam, undecanolactam, and lauryllactam, in particular lauryllactam.

Said C4-C36 aliphatic diamine Ca is linear or branched and is chosen in particular from butanediamine, 1,5-pentamethyldiamine, 2-methyl-l, 5-pentanediamine, 1,6-hexamethylenediamine and 1,7-heptanediamine , 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-l, 8-octane-diamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,10 -decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-

1,5-pentanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1,20-eicosanediamine, 1 , 22-docosanediamine and fatty acid dimers.

Said C6-C18 aliphatic diamine Ca is linear or branched and is chosen in particular from 1,6-hexamethylenediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1 , 8-octane-diamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,10-decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-

1,5-pentanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine.

Said C6-C12 aliphatic diamine Ca is linear or branched and is chosen in particular from 1,6-hexamethylenediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1 , 8-octane-diamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,10-decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-

1,5-pentanediamine, 1,12-dodecanediamine. Said C10-C12 aliphatic diamine Ca is linear or branched and is chosen in particular from 1,10-decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-l, 5-pentanediamine, 1,12- dodecanediamine.

Said dicarboxylic acid Cb C4-C36, preferably C6-C18, preferably C6-C12, more preferably _C8-C12;

Said Cb C4-C36 dicarboxylic acid is aliphatic and linear and is in particular chosen from succinic acid, pentanedioic acid, adipic acid, heptanedioic acid, suberic acid, azelaic acid, acid sebacic, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid and docosanedioic acid.

Said Cb C6-C18 dicarboxylic acid is aliphatic and linear and is chosen in particular from adipic acid, heptanedioic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioiic acid, octadecanedioic acid.

Said Cb C6-C12 dicarboxylic acid is aliphatic and linear and is chosen in particular from adipic acid, heptanedioic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic.

Said dicarboxylic acid Cb _C8-C12, is aliphatic and linear and is especially selected from suberic acid, azelaic acid, sebacic acid, undecanedioic acid and

dodecanedioic.

In said XY aliphatic repeating unit, said diamine X can in particular be a cycloaliphatic diamine chosen from bis (3,5-dialkyl-4-aminocyclohexyl) methane, bis (3,5-dia Ikyl-4-aminocyclohexyl) ethane, bis (3,5-dialkyl-4-aminocyclo-hexyl) propane, bis (3,5-dialkyl-4-aminocyclo-hexyl) butane, bis- (3-methyl-4-aminocyclohexyl) -methane (BMACM or MACM), p-bis (aminocyclohexyl) -methane (PACM) and risopropylidenedi (cyclohexylamine) (PACP), isophoronediamine, piperazine, amino-ethylpiperazine.

It can also include the following carbon skeletons: norbornyl methane, cyclohexylmethane, dicyclohexylpropane, di (methylcyclohexyl), di (methylcyclohexyl) propane. A non-exhaustive list of these cycloaliphatic diamines is given in the publication "Cycloaliphatic Amines" (Encyclopaedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pp. 386-405).

In said XY aliphatic repeating unit, said XY diamine can in particular be an aliphatic diamine that is linear or branched and is chosen from that defined above for the diamine in Ca. In said aliphatic repeating unit XY, the diacid Y can be an aromatic dicarboxylic acid chosen from terephthalic (denoted T), isophthalic (denoted I) and diacids.

naphthalenics.

In said XY aliphatic repeating unit, the Y diacid can be an Y aliphatic dicarboxylic acid and is chosen from that defined above for the Cb diacid.

It is obvious that the XY unit is different from the Cb diamine unit. Cb diacid.

Advantageously, A is an aliphatic repeating unit obtained by polycondensation of at least one C ₅ to Cis amino acid, preferably C ₆ to Cu, more preferably Cio to C12, or of at least one C ₅ to Cis lactam, preferably C ₆ to C12, more preferably C10 to C12.

Advantageously, XY is an aliphatic repeating unit obtained by polycondensation of at least one cycloaliphatic diamine, and of at least one aromatic dicarboxylic acid or of at least one aliphatic dicarboxylic acid Y.

Advantageously, A is an aliphatic repeating unit obtained by polycondensation of at least one C ₅ to Cis amino acid, preferably C ₆ to C12, more preferably Cio to C12, or of at least one C ₅ to Cis lactam, preferably C ₆ to C12, more preferably Cio to C12 and XY is an aliphatic repeating unit obtained by polycondensation of at least one cycloaliphatic diamine, and of at least one aromatic dicarboxylic acid or of at least one aliphatic dicarboxylic acid Y .

Advantageously, A is an aliphatic repeating unit obtained by polycondensation of at least one Cio to C12 amino acid, or of at least one Cio to C12 lactam and XY is an aliphatic repeating unit obtained by polycondensation of at least one cycloaliphatic diamine , and at least one aromatic dicarboxylic acid or at least one aliphatic dicarboxylic acid Y.

Advantageously, said amorphous polyamide is chosen from among 11 / B10, 12 / B10, 11 / BI / BT, 11 / BI in particular 11 / B10.

Advantageously, A is an aliphatic repeating unit obtained by polycondensation of at least one Cio to C12 amino acid, or of at least one Cio to C12 lactam and XY is an aliphatic repeating unit obtained by polycondensation of at least one cycloaliphatic diamine , and at least one aromatic dicarboxylic acid.

Advantageously, said amorphous polyamide is chosen from 11 / BI / BT and 11 / BI.

Advantageously, A is an aliphatic repeating unit obtained by polycondensation of at least one Cio to C12 amino acid, or of at least one Cio to C12 lactam and XY is an aliphatic repeating unit obtained by polycondensation of at least one cycloaliphatic diamine , and at least one aliphatic dicarboxylic acid Y. Advantageously, said amorphous polyamide is chosen from 11 / B10, 12 / B 10, in particular 11 / B10. Advantageously, said alloy consists of a single polyamide which is an amorphous polyamide and of a mixture of a grafted polyolefin based on polypropylene and an ungrafted polyolefin based on polypropylene.

In a second variant, said alloy consists of a single semi-crystalline polyamide or of a mixture of two semi-crystalline polyamides and at least one polyolefin.

The polyolefin is as defined above.

Semi-crystalline polyamide:

The semi-crystalline polyamide may be chosen from aliphatic polyamides, in particular long chain polyamides, arylaliphatic polyamides and semi-aromatic polyamides.

The expression “aliphatic polyamide” means a homopolyamide or a copolyamide. It is understood that this may be a mixture of aliphatic polyamides.

The expression “long chain” means that the average number of carbon atoms per nitrogen atom is greater than 8, in particular between 9 and 18.

In one embodiment, said mixture of polyamides is a mixture of an aliphatic polyamide, in particular of a long chain, with an aryl-aliphatic polyamide.

The aliphatic polyamide can be obtained from the polycondensation of a lactam, said lactam can be chosen from pyrrolidinone, 2-piperidinone, caprolactam,

enantholactam, caprylolactam, pelargolactam, decanolactam, undecanolactam, and lauryllactam, in particular lauryllactam.

The aliphatic polyamide can be obtained from the polycondensation of an amino acid which can be selected from 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid as well as its derivatives, in particular N-heptyl-11-aminoundecanoic acid, in particular 11-aminoundecanoic acid.

The aliphatic polyamide can be obtained from the polycondensation of a unit X1Y1, XI representing a diamine and Y representing a dicarboxylic acid.

XI can be a linear or branched C5 to C18 aliphatic diamine, and can in particular be chosen from 1,5-pentamethyldiamine, 2-methyl-l, 5-pentanediamine, 1,6-hexamethylenediamine and 1,7 -heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-l, 8-octane-diamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1 , 10-decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1, 16-hexadecanediamine and 1,18-octadecanediamine. Advantageously, the diamine XI used is C6 to C12, in particular chosen from 2-methyl-l, 5-pentanediamine, 1,6-hexamethylenediamine, 1,7-heptanediamine, 1,8-octanediamine, 1, 9- nonanediamine, 2-methyl-l, 8-octane-diamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,10-decanediamine, 1,11-undecanediamine, 2 -butyl-2-ethyl-1,5-pentanediamine, 1,12-dodecanediamine.

Advantageously, the diamine XI used is C10 to C12, in particular chosen from 1,10-decanediamine, 1,11-undecanediamine, 2-butyl-2-ethyl-l, 5-pentanediamine and 1,12-dodecanediamine ,

Y1 can be C6 to C18 aliphatic dicarboxylic acid, in particular C6 to C12, especially C10 to C12.

The C6 to C18 aliphatic dicarboxylic acid Y1 can be chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, l 'tetradecanedioic acid, pentadecanedioic acid,

hexadecanedioiic acid, octadecanedioic acid.

The C6 to C12 aliphatic dicarboxylic acid Y1 can be chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid. The C10 to C12 aliphatic dicarboxylic acid Y1 can be chosen from sebacic acid, undecanedioic acid and dodecanedioic acid.

Advantageously, said aliphatic polyamide is chosen from PA6, PA66, PA610, PA612,

PA1010, PA1012, PA1212, PAU and PA 12, in particular PA1010, PA1012, PA1212, PAU and PA 12. The expression “aryl-aliphatic polyamide” means a polyamide obtained from

polycondensation of a unit X2Y1, X2 representing an aryldiamine and Y1 representing an aliphatic dicarboxylic acid as defined above.

Said aryldiamine X2 can be chosen from meta-xylylenediamine (MXD) and para-xylylenediamine (PXD).

Advantageously, said aryl-aliphatic polyamide is chosen from MXD6, MXD10, MXD12.

Advantageously, said arylaliphatic polyamide is chosen from MXD10, MXD12.

Advantageously, said mixture of two semi-crystalline polyamides is a mixture of an aliphatic polyamide with an arylaliphatic polyamide.

Advantageously, said mixture of two semi-crystalline polyamides is a mixture of an aliphatic polyamide chosen from PA6, PA66, PA610, PA612, PA1010, PA1012, PA1212, PAU and PA 12, in particular PA1010, PA1012, PA1212, PAU and PA 12, with an arylaliphatic polyamide chosen from MXD6, MXD10, MXD12. Advantageously, said mixture of two semi-crystalline polyamides is a mixture of an aliphatic polyamide chosen from PA1010, PA1012, PA1212, PAU and PA 12, with an arylaliphatic polyamide chosen from MXD10, MXD12.

The expression “semi-aromatic polyamide” means in particular a semi-aromatic polyamide of formula as described in EP1505099, in particular a semi-aromatic polyamide of formula B / ZT in which B is chosen from a unit obtained from the polycondensation of d an amino acid as defined above, a unit obtained from the polycondensation of a lactam as defined above and a unit corresponding to the formula X2Y2, with X2 and Y2 being as defined above;

ZT denotes a unit obtained from the polycondensation of a Cx diamine and terephthalic acid, with x representing the number of carbon atoms of the Cx diamine, x being between 4 and 36, advantageously between 6 and 18, preferably between 6 and 12,

advantageously between 10 and 12, in particular a polyamide of formula A / 6T, A / 9T, A / 10T or A / 11T, A being as defined above, in particular a polyamide PA 6 / 6T, a PA 66 / 6T , a PA 6I / 6T, a PA 11 / 9T, a PA 11 / 10T, a PA 11 / 12T, a PA 12 / 9T, a PA 12 / 10T, a PA 12 / 12T, a PA MPMDT / 6T, a PA MXDT / 6T, one PA 11 / 6T / 10T, one PA MXDT / 10T, one PA MPMDT / 10T, one PA BACT / 10T, one PA BACT / 6T, PA BACT / 10T / 6T, one PA 11 / BACT / 10T, a PA 11 / MPMDT / 10T and a PA 11 / MXDT / 10T, and block copolymers, in particular polyamide / polyether (PEBA).

T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylene diamine and BAC corresponds to bis (aminomethyl) cyclohexane (1.3 BAC and / or 1, 4 BAC).

Advantageously, the semi-aromatic polyamide is chosen from PA11 / 9T, PA11 / 10T, PA 11 / 12T, PA12 / 9T, PA12 / 10T, PA12 / 12T.

Advantageously, said at least one polyamide is chosen from a single amorphous polyamide, an aryl-aliphatic polyamide, a mixture of an aliphatic polyamide, in particular a long-chain polyamide, with an aryl-aliphatic polyamide and a mixture of an aliphatic polyamide, in particular with long chain with a semi-aromatic polyamide.

Advantageously, said alloy consists of a mixture of two semi-crystalline polyamides and of a mixture of a grafted polyolefin based on polypropylene and an ungrafted polyolefin is based on polypropylene.

In one embodiment, the present invention relates to the use as defined above, in which the composition comprises additives.

Additives The additives can be present up to 2% by weight relative to the total weight of the composition, in particular they are present from 1 to 2% by weight relative to the total weight of the composition. The additive can be selected from a catalyst, an antioxidant, a heat stabilizer, a UV stabilizer, a light stabilizer, a lubricant, a flame retardant, a nucleating agent, a chain extender and a colorant.

The term “catalyst” denotes a polycondensation catalyst such as an inorganic or organic acid.

Advantageously, the proportion by weight of catalyst is from about 50 ppm to about 5000 ppm, in particular from about 100 to about 3000 ppm relative to the total weight of the composition.

Advantageously, the catalyst is chosen from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or a mixture of these.

The antioxidant can in particular be an antioxidant based on a copper complex of 0.05 to 5% by weight, preferably from 0.05 to 1% by weight, preferably from 0.1 to 1%.

The expression copper complex denotes in particular a complex between a monovalent or divalent salt of copper with an organic or inorganic acid and an organic ligand.

Advantageously, the copper salt is chosen from cupric (Cu (II)) salts of hydrogen halide, cuprous (Cu (l)) salts of hydrogen halide and salts of aliphatic carboxylic acids.

In particular, the copper salts are chosen from CuCl, CuBr, Cul, CuCN, CuCl2, Cu (OAc) 2, cupric stearate.

Copper complexes are described in particular in US3505285.

Said copper-based complex may further comprise a ligand chosen from phosphines, in particular triphenylphosphines, mercaptobenzimidazole, EDTA, acetylacetonate, glycine, ethylene diamine, oxalate, diethylene diamine, triethylene tetraamine, pyridine, tetrabromobisphenyl-A, tetrabisphenyl-A derivatives, such as epoxy derivatives, and chloro dimethanedibenzo (a, e) cyclooctene derivatives and mixtures thereof. diphosphone and dipyridyl or their mixtures, in particular triphenylphosphine and / or mercaptobenzimidazole.

Phosphines denote alkylphosphines, such as tributylphosphine or arylphosphines such as triphenylphosphine (TPP).

Advantageously, said ligand is triphenylphosphine.

Examples of complexes as well as their preparation are described in patent CA 02347258. Advantageously, the amount of copper in the composition of the invention is from 10 ppm to 1000 ppm by weight, in particular from 20 ppm to 70 ppm, in particular from 50 to 150 ppm relative to the total weight of the composition.

Advantageously, said copper-based complex further comprises a halogenated organic compound.

The halogenated organic compound can be any halogenated organic compound.

Advantageously, said halogenated organic compound is a bromine-based compound and / or an aromatic compound.

Advantageously, said aromatic compound is chosen in particular from decabromediphenyl, decabromodiphenyl ether, oligomers of bromo or chloro styrene, polydibromostyrene, Advantageously, said halogenated organic compound is a compound based on bromine.

Said halogenated organic compound is added to the composition in a proportion of 50 to 30,000 ppm by weight of halogen relative to the total weight of the composition, in particular from 100 to 10,000, in particular from 500 to 1,500 ppm.

Advantageously, the copper: halogen molar ratio is from 1: 1 to 1: 3000, in particular from 1: 2 to 1: 100.

In particular, said ratio is from 1: 1.5 to 1:15.

Advantageously, the antioxidant based on a copper complex.

The heat stabilizer can be an organic stabilizer or more generally a combination of organic stabilizers, such as a primary antioxidant of phenol type (for example of the type of that of irganox 245 or 1098 or 1010 from the company Ciba), a secondary antioxidant of phosphite type.

The UV stabilizer can be a HALS, which means Hindered Amine Light Stabilizer or an anti-UV (for example Tinuvin 312 from the company Ciba).

The light stabilizer may be of the hindered amine type (for example Tinuvin 770 from the company Ciba), a phenolic or phosphorus-based stabilizer.

The lubricant can be a fatty acid type lubricant such as stearic acid.

The flame retardant can be a halogen-free flame retardant, as described in US

2008/0274355 and in particular a phosphorus-based fire-retardant, for example a metal salt chosen from a metal salt of phosphinic acid, in particular salts of dialkyl phosphinate, in particular diethylphosphinate aluminum salt or

aluminum diethylphosphinate, a metal salt of diphosphinic acid, a mixture of flame retardant based on aluminum phosphinate and a synergist of nitrogen or a mixture of flame retardant based on aluminum phosphinate and 'a phosphorus synergist, a polymer containing at least one metal salt of phosphinic acid, in particular on an ammonium base such an ammonium polyphosphate, sulfamate or pentaborate, or on a melamine base such as melamine, melamine salts, melamine pyrophosphates and melamine cyanurates, or on a cyanuric acid base, also a polymer containing at least one metal salt of diphosphinic acid or red phosphorus, an oxide of antimony, an oxide of zinc, an oxide of iron, an oxide of magnesium or metal borates such as zinc borate, or phosphazene, phospham or a phosphoxynitride or a mixture thereof. They can also be halogenated flame retardants such as brominated or polybrominated polystyrene, brominated polycarbonate or brominated phenol.

The nucleating agent can be silica, alumina, clay or talc, in particular talc.

Examples of suitable chain regulators are monoamines, acids

monocarboxylic acids, diamines, triamines, dicarboxylic acids, acids

tricarboxylic acids, tetraamines, tetracarboxylic acids and, oligoamines or oligocarboxylic acids having in each case 5 to 8 amino or carboxy groups respectively and in particular dicarboxylic acids, tricarboxylic acids or a mixture of dicarboxylic acids and tricarboxylic acids . For example, it is possible to use dodecanedicarboxylic acid as dicarboxylic acid and trimellitic acid as tricarboxylic acid.

In another embodiment, the present invention relates to the use as defined above, in which the composition comprises at least one prepolymer, in particular

monofunctional NH2, in particular based on PAU.

Advantageously, the composition comprises a single prepolymer.

The prepolymer

The prepolymer can be present up to 11% by weight relative to the total weight of the composition, in particular from 0.1% to 11% by weight relative to the total weight of the composition.

The prepolymer is different from the nucleating agent used as an additive.

The term "prepolymer" refers to polyamide oligomers necessarily of lower number average molecular weight than that of the polyamides used in the composition, in particular said prepolymer with a number average molecular weight of from 1000 to 15000 g / mole, in particular. in particular from 1000 to 10000 g / mole.

The prepolymer can be chosen from oligomers of aliphatic, linear or branched polyamides, oligomers of cycloaliphatic polyamides, oligomers of semi-aromatic polyamides, oligomers of aromatic polyamides, aliphatic, linear or branched polyamides, cycloaliphatic, semi-aromatic and aromatics having the same definition as above. The prepolymer or oligomer therefore results from the condensation:

- at least one lactam, or

- at least one amino acid, or

- of at least one diamine with at least one dicarboxylic acid, or a mixture of these.

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

The prepolymer can also be a copolyamide oligomer or a mixture of polyamide and copolyamide oligomers.

For example, the prepolymer is monofunctional NH2, monofunctional CO2H, or difunctional CO2H or NH2.

The prepolymer can therefore be mono or difunctional, acid or amine, that is to say that it has a single terminal amine or acid function, when it is monofunctional (in this case the other termination is non-functional, in particular CH3), or two terminal amine functions or two terminal acid functions, when it is difunctional.

Advantageously, the prepolymer is monofunctional, preferably NH2 or CO2H.

It can also be non-functional at both terminations, in particular diCH3.

In one embodiment, the present invention relates to the use as defined above, in which the composition comprises:

30 to 70%, in particular 35 to 60%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the polyamide ratio / polyolefin being comprised from 95/5 to 50/50;

30 to 70%, in particular 40 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%;

0 to 5% loads and

0 to 2%, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

In another embodiment, the present invention relates to the use as defined above, in which the composition consists of:

30 to 70%, in particular 35 to 60%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the polyamide ratio / polyolefin being comprised from 95/5 to 50/50;

30 to 70%, in particular 40 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and 0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%;

0 to 5% loads and

0 to 2%, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

In one embodiment, the present invention relates to the use as defined above, in which the composition comprises:

30 to 50%, in particular 35 to 50%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the polyamide ratio / polyolefin being comprised from 95/5 to 50/50;

50 to 70%, in particular 50 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%;

0 to 5% loads and

0 to 2%, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

In yet another embodiment, the present invention relates to the use as defined above, in which the composition consists of:

30 to 50%, in particular 35 to 50%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the polyamide ratio / polyolefin being comprised from 95/5 to 50/50;

50 to 70%, in particular 50 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%;

0 to 5% loads and

0 to 2%, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

According to another aspect, the present invention relates to a composition useful in particular for injection molding, comprising:

30 to 70%, in particular 35 to 60%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the polyamide ratio / polyolefin being comprised from 95/5 to 50/50;

30 to 70%, in particular 40 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%; 0 to 5% loads and

0 to 2, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

Advantageously, said composition, in particular useful for injection molding, consists of:

30 to 70%, in particular 35 to 60%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the ratio

polyamide / polyolefin being comprised from 95/5 to 50/50;

30 to 70%, in particular 40 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%;

0 to 5% loads and

0 to 2, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

In one embodiment, said composition useful in particular for injection molding, is comprises:

30 to 50%, in particular 35 to 50%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the ratio

polyamide / polyolefin being comprised from 95/5 to 50/50;

50 to 70%, in particular 50 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%;

0 to 5% loads and

0 to 2%, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

In another embodiment, said composition useful in particular for injection molding, consists of:

30 to 50%, in particular 35 to 50%, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above, the ratio

polyamide / polyolefin being comprised from 95/5 to 50/50;

50 to 70%, in particular 50 to 65%, and more particularly 50 to 60% by weight of a mixture of solid and hollow glass reinforcement as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%; 0 to 5% loads and

0 to 2%, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

In one embodiment, said composition is devoid of polyamide 6 and 66.

All the characteristics defined above for the use defined above are valid for the composition as such.

Regarding charges

The composition can moreover also comprise fillers. The fillers envisaged include conventional mineral fillers, such as kaolin, magnesia, slags, carbon black, expanded or non-expanded graphite, wollastonite, pigments such as titanium oxide and zinc sulphide, antistatic charges.

Advantageously, said composition, in particular useful for injection molding, consists of:

30 to 70% by weight, in particular 35 to 60% by weight, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined above , the polyamide / polyolefin ratio being from 95/5 to 50/50;

30 to 70% by weight, in particular 40 to 65% by weight, and more particularly 50 to 60% by weight of a mixture of reinforcing solid and hollow glass as defined above; and

0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11% by weight;

0 to 5% by weight of fillers and

0 to 2% by weight, preferably 1 to 2% by weight of additives,

the sum of the proportions of each constituent of said composition being equal to 100%.

According to another aspect, the present invention relates to the use of a composition as defined above, for the manufacture of an article in particular for electronics, for telecom applications or for the exchange of data, such as for an autonomous vehicle or for applications connected to each other.

Advantageously, said article is produced by injection molding.

In other words, the present invention relates to a method of preparing an article in particular for electronics, for telecom applications or for the exchange of data, such as for an autonomous vehicle or for applications connected to each other comprising a step, in particular by injection molding, of a composition as defined above.

According to another aspect, the present invention relates to an article obtained by injection molding with a composition as defined above.

[Examples] The present invention will now be illustrated in more detail by means of the following examples without being limited thereto.

The various polyamides and copolyamides of the invention were prepared according to the usual technique for the synthesis of polyamides and copolyamides.

Synthesis of CoPa 11 / 10T representative of the different copolyamides:

the monomers aminoundecanoic acid, decanediamine and terepthalic acid are loaded together into the reactor according to the desired mass ratio. The medium is first inerted in order to remove the oxygen which can generate yellowing or side reactions. Water can also be charged to improve heat exchange. Two stages of temperature and pressure rise are achieved. The temperature (T °) and pressure conditions are chosen in order to allow the medium to be in the molten state. After reaching the maintenance conditions, degassing takes place to allow the polycondensation reaction. The medium gradually becomes viscous and the water of reaction formed is entrained by flushing with nitrogen or placed under vacuum. When the stop conditions are reached, in relation to the desired viscosity, the agitation is stopped and the extrusion and the granulation can start.

The compositions in Table 1 were prepared (% by weight) according to the following general protocol:

Compounding for the preparation of the granules of the said formulations:

Coperion ZSK 26 MC twin-screw extruder with at least 1 lateral feed path for raw materials

Machine temperature: 270C

Screw speed: 250 rpm

Extruder output rate: 16 kg / h

Transformation:

Plates 100x100x2 mm3 were produced by injection molding for the measurements of the dielectric properties. The following parameters were used:

- ENGEL VICTORY 500, 160T hydraulic press

- Injection temperature (supply / nozzle): 265C / 280C

- Mold temperature: 100C

- Holding time: 10s

- Material holding pressure: 700 bars

- Cooling time: 35s

Dumbbells according to ISO 527-2 IA were produced by injection molding for the measurements of the mechanical properties in traction. The following parameters were used:

- ENGEL VICTORY 500, 160T hydraulic press - Injection temperature (supply / nozzle): 285C / 295C

- Mold temperature: 100C

- Holding time: 10s

- Material holding pressure: 700 bars

- Cooling time: 15s

The results obtained from the compositions of the invention are shown in Table 1 and Table 2 below:

[Table 1]

[Table 2]

The comparative compositions are presented in Table 3 below:

[Table 3]

He to 19: Invention 1 to 9

Cl to C13: Comparative compositions Cl to C13

N / A: Not tested

PAU: Rilsan (Arkema)

PA11 / 10T (28/72 per weight)

PA11 / B10 (10/90 per weight)

Polypropylene PPH 5060: ungrafted polypropylene homopolymer from Total

Orevac CA 100: polypropylene grafted maleic anhydride (Arkema)

PA oligo: PAU mono NH2

Antioxidant corresponds to an antioxidant of the phenolic type.

Secondary antioxidant corresponds to an antioxidant of the phosphite type.

NE glass fibers: solid glass fibers with flat section NE Nitto Boseki

Glass fibers E: solid glass fibers with circular cross section E Nitto Boseki or Nippon Electric Glass FIM glass fibers: solid fibers with circular cross section from AGY (high modulus glass fibers)

Glass beads: Flollowlite hollow glass beads

Dk, tan delta are measured according to ASTM D-2520-13

The tensile modulus (or modulus of elasticity E) is measured according to ISO standard 527-1 and 2: 2012.

Claims

1. Use of a mixture of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin, said mixture of solid and hollow glass reinforcements comprising from 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, in particular 5 to 35% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements, excluding polyamide 6 and 66, to prepare a composition having a modulus, dry at 23 ° C, at least equal to 8GPa, in particular at least equal to 10 GPa, in particular at least equal to llGPa, and a dielectric constant Dk, less than or equal to 3, 5, in particular less than or equal to 3.3, in particular less than or equal to 3.2 as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, in particular at a frequency of at least 2 GHz, especially at a frequency of at least 3 GHz, at 23 ° C, under 50% RH. 2. Use according to claim 1, wherein the dielectric loss (tan delta) of said composition is less than or equal to 0.01, as measured on a dry sample, at 23 ° C, under 50% RH, at a frequency of at least 1 GHz, in particular a frequency up to 2.4 GHz, according to ASTM D-2520-13. 3. Use according to claim 1 or 2, wherein said mixture of solid and hollow glass reinforcements, in addition to the hollow glass beads, comprises glass fibers. solid selected from circular section glass fibers, flat section glass fibers and a mixture of these. 4. Use according to claim 3, wherein the mixture of glass reinforcements is consisting of 50 to 95% by weight of solid glass fibers and 5 to 50% by weight of hollow glass beads, in particular 65 to 95% by weight of solid glass fibers and 5 to 35% by weight of beads of hollow glass. 5. Use according to one of claims 1 to 4, wherein said alloy consists of at least one polyamide and at least one polyolefin whose ratio by weight polyamide / polyolefin ranges from 95/5 to 50/50. 6. Use according to one of claims 1 to 5, wherein said at least one polyolefin is chosen from grafted polyolefins and ungrafted polyolefins and a mixture of these, in particular a mixture thereof. 7. Use according to claim 6, in which the reactive units of the grafted polyolefin are chosen from esters of unsaturated carboxylic acids such as, for example, alkyl acrylates or alkyl methacrylates, preferably said alkyls having from 1 with 24 carbon atoms, examples of alkyl acrylate or methacrylate are in particular methyl methacrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2 -ethylhexyl; vinyl esters of saturated carboxylic acids such as, for example, vinyl acetate or propionate. 8. Use according to claim 6 or 7, in which the grafted polyolefin is based on propylene. 9. Use according to claim 6, wherein the ungrafted polyolefin is chosen from ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4 - methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene , 1-dococene, 1 le - tetracocene, 1-hexacocene, 1-octacocene and 1-triacontene, preferably propylene or ethylene or dienes such as for example butadiene, isoprene or 1 , 4-hexadiene. 10. Use according to one of claims 6 and 9, wherein the ungrafted polyolefin is based on propylene. 11. Use according to one of claims 5 to 10, wherein said alloy consists of at least one polyamide and a mixture of a grafted polyolefin based on polypropylene and an ungrafted polyolefin based on polypropylene. . 12. Use according to one of claims 1 to 11, wherein said at least one polyamide is chosen from semi-crystalline polyamides, amorphous polyamides and a mixture of these. 13. Use according to one of claims 1 to 12, wherein said alloy consists of a single polyamide which is an amorphous polyamide and at least one polyolefin. 14. Use according to claim 13 wherein said amorphous polyamide is a polyamide of formula A / XY, wherein: A is an aliphatic repeating unit obtained by polycondensation: at least one C ₆ to Cis amino acid, preferably C ₆ to Cu, more preferably Cio to C12, or at least one C ₆ to Cis lactam, preferably C ₆ to C12, more preferably Cio to C12, or of at least one C4-C36 aliphatic diamine Ca, preferably C6-C18, preferably C6-C12, more preferably C10-C12 with at least one dicarboxylic acid Cb C4-C36, preferably C6-C18, preferably C6-C12, more preferably _C8-C12; XY is an aliphatic repeating unit obtained by polycondensation: of at least one cycloaliphatic diamine, or of at least one linear or branched aliphatic diamine X and at least one aromatic dicarboxylic acid or at least one aliphatic dicarboxylic acid Y. 15. Use according to claim 13 or 14, wherein said amorphous polyamide is chosen from 11 / B10, 12 / B10, 11 / BI / BT, 11 / BI in particular 11 / B10. 16. Use according to one of claims 1 to 12, wherein said alloy consists of a single semi-crystalline polyamide or of a mixture of two semi-crystalline polyamides and at least one polyolefin. 17. Use according to claim 16, in which the semi-crystalline polyamide is chosen from aliphatic polyamides, in particular long-chain polyamides, arylaliphatic polyamides and semi-aromatic polyamides. 18. Use according to claim 16 or 17, in which said mixture of polyamides is a mixture of an aliphatic polyamide, in particular a long chain, with an arylaliphatic polyamide. 19. Use according to claim 17 or 18, in which the aliphatic polyamide is chosen from PA610, PA612, PA1010, PA1012, PA1212, PAU and PA 12, in particular PA1010, PA1012, PA1212, PAU, PA 12. 20. Use according to claim 17 or 18, in which the aryl-aliphatic polyamide is chosen from MXD6, MXD10, MXD12. 21. Use according to claim 17, in which the semi-aromatic polyamide is chosen from PA11 / 9T, PA11 / 10T, PA 11 / 12T, PA12 / 9T, PA12 / 10T, PA12 / 12T. 22. Use according to one of claims 11 to 15, wherein said alloy consists of a single polyamide which is an amorphous polyamide and of a mixture of a grafted polyolefin based on polypropylene and an ungrafted polyolefin. polypropylene based. 23. Use according to one of claims 11 and 16 to 21, wherein said alloy is consisting of a mixture of two semi-crystalline polyamides and a mixture of a grafted polyolefin based on polypropylene and an ungrafted polyolefin is based on polypropylene. 24. Use according to one of claims 1 to 23, wherein the composition comprises additives. 25. Use according to one of claims 1 to 24, in which the composition comprises at least one prepolymer, in particular monofunctional NH2, in particular based on PAU, 26. A composition useful in particular for injection molding, comprising: 30 to 70% by weight, in particular 35 to 60% by weight, and more particularly 40 to 50% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, as defined in one of claims 1 to 23, the polyamide / polyolefin ratio being from 95/5 to 50/50; 30 to 70% by weight, in particular 40 to 65% by weight, and more particularly 50 to 60% by weight of a mixture of reinforcing solid and hollow glass as defined in one of claims 1 to 23; excluding polyamide 6 and 66, and 0 to 11% by weight of at least one prepolymer, in particular 0.1 to 11%; 0 to 5% by weight of fillers and 0 to 2% by weight, preferably 1 to 2% by weight of additives, the sum of the proportions of each constituent of said composition being equal to 100%. 27. Use of a composition as defined in one of claims 1 to 25, for the manufacture of an article, in particular for electronics, for telecom applications or for the exchange of data, such as for a autonomous vehicle or for applications connected to each other. 28. Use according to claim 27, characterized in that the article is produced by injection molding. 29. Article obtained by injection molding with a composition as defined in one of claims 1 to 25.