Copolyamide, composition comprising such a copolyamide and their uses

1. A composition consisting of (1) a transparent copolyamide consisting of two units and having the formula:

A/(diamine).(Cw diacid),

in which:

the diamine is a cycloaliphatic diamine, that is 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 (MACM), p-bis(aminocyclohexyl)methane (PACM) or isopropylidenedi(cyclohexylamine) (PACP),

Cw diacid is succinic acid (w=4), adipic acid (w=6), heptanedioic acid (w=7), azelaic acid (w=9), sebacic acid (w=10), undecanedioic acid (w=11), dodecanedioic acid (w=12), brassylic acid (w=13), tetradecanedioic acid (w=14), hexadecanedioic acid (w=16), octadecanedioic acid (w=18), octadecenedioic acid (w=18), eicosanedioic acid (w=20), docosanedioic acid (w=22) or dimer fatty acids having 36 carbons and

A is a unit obtained from N-heptyl-11-aminoundecanoic acid and in which A or the Cw diacid are obtained, in all or part, from renewable starting materials according to Standard ASTM D6866 in order for the content, expressed as percentage, of renewable organic carbon in the copolyamide, denoted % C renew.org , to be greater than or equal to 20%, the content %C renew.org corresponding to the following equation (I):

%

⁢

⁢

C

renew

.

org

=

∑

i

⁢

⁢

Fi

×

Ci

+

∑

k

⁢

⁢

Fk

×

Ck

′

(

∑

j

⁢

⁢

Fj

×

Cj

+

∑

i

⁢

⁢

Fi

×

Ci

+

∑

k

⁢

⁢

Fk

×

Ck

)

×

100

(

I

)

with i =monomer(s) resulting from 100% renewable starting materials, within the meaning of Standard ASTM D6866

j =monomer(s) resulting from 100% fossil starting materials, within the meaning of Standard ASTM D6866

k =monomer(s) resulting in part from renewable starting materials, within the meaning of Standard ASTM D6866

Fi, Fj, Fk =respective molar fraction(s) of the monomers i, j and k in the copolyamide

Ci, Cj, Ck =respective number of carbon atoms of the monomers i, j and k in the copolyamide,

Ck′ =number of atoms of renewable organic carbon, within the meaning of Standard ASTM D6866, in the monomer(s) k, wherein

the molar content of A is between 20 and 82%, and

the molar contents of cycloaliphatic diamine and of Cw diacid are each between 9 and 40%,

(2) optionally a second polymer that is PLA, PGA, PHA or a polysaccharide, and

(3) optionally additives that are fillers, fibers, dyes, stabilizers, plasticizers, impact modifiers, “surfactants, pigments, brighteners, antioxidants, or waxes, wherein said transparent copolyamide exhibits an enthalpy of fusion of between 0 and 23 J/g”.

2. The copolyamide according to claim 1 is of the formula 11/B.10, 11/P.10, 11/B.12, 11/P.12, 11/B.14, 11/P.14, 11/B.18 or 11/P.18 wherein 11 is N-heptyl-11-aminoundecanoic acid.

3. The composition according to claim 1 , wherein at least one second polymer (2) is present.

4. The composition according to claim 1 , wherein the second polymer is obtained, in all or part, from a renewable starting material according to Standard ASTM D6866.

5. The composition according to claim 1 , additionally comprising at least one additive of natural and renewable origin according to Standard ASTM D6866, that is fillers, fibres, dyes, stabilizers, plasticizers, impact modifiers, surfactants, pigments, brighteners, antioxidants, natural waxes or their mixtures.

6. In a monolayer structure, or a multilayer structure, the

improvement wherein the mono layer structure or at least one layer of the multilayer structure comprises a composition according to claim 1 .

7. A mono- or multilayer structure according to claim 6 , wherein the structure is provided in the form of fibres, of a film, of a pipe, of a hollow body or of an injected component.

8. Lenses, spectacle lenses or spectacle frames, comprising in said lenses or frames a copolymer according to claim 1 .