Polyamide hose for compressed air

1. A multilayer hose for compressed air consisting of, in this order:

an outer layer (1) made of polyamide, and

an inner layer (3) of a polymer having a flexural modulus of greater than 1100 MPa, the inner layer (3) being in contact with compressed air, wherein said inner layer polymer (3) is three adjacent layers successively composed of a layer of polymer having a flexural modulus of greater than 1100 MPa, of a braid and of a layer of polymer having a flexural modulus of greater than 1100 MPa, wherein the polyamide of the outer layer (1) is chosen from:

PA11,

PA12,

a polyamide A corresponding to the formula X,Y/Z or 6,Y2/Z, in which:

X denotes the residues of an aliphatic diamine having from 6 to 10 carbon atoms,

Y denotes the residues of an aliphatic dicarboxylic acid having from 10 to 14 carbon atoms,

Y2 denotes the residues of an aliphatic dicarboxylic acid having from 15 to 20 carbon atoms,

Z denotes at least one unit chosen from the residues of a lactam, the residues of an α,ω-aminocarboxylic acid and the unit X1, Y1 in which X1 denotes the residues of an aliphatic diamine and Y1 denotes the residues of an aliphatic dicarboxylic acid, the ratios by weight Z/(X+Y+Z) and Z/(6+Y2+Z) being between 0 and 15%, and

a semiaromatic polyamide B,

wherein at least one of the layers contains a product which facilitates adhesion to the adjacent layer.

2. A multilayer hose for compressed air consisting of, in this order:

an outer layer (1) made of polyamide,

an inner layer (2) of a polymer having a flexural modulus of less than 500 MPa, wherein said polymer is selected from the group consisting of ethylene copolymer(s) and propylene copolymer(s),

an intermediate layer (3) of a polymer having a flexural modulus of greater than 1100 MPa, the inner layer (3) being in contact with compressed air, wherein said inner layer polymer (3) is selected from the group consisting of polycarbonate (PC), polyphenyene sulfide (PPS), polyphenylene oxide (PPO) and a polyamide selected from the group consisting of PA 6, PA 6,6, PA 6,10, PA 6,12, an aromatic polyamide and a semiaromatic polyamide, or inner layer (3) optionally is replaced by three adjacent layers successively composed of a layer of polymer having a flexural modulus of greater than 1100 MPa, of a braid and of a layer of polymer having a flexural modulus of greater than 1100 MPa,

optionally a layer (4) of a polymer having a flexural modulus of less than 500 MPa, and

an inner layer (5) of a polymer chosen from polyamides, blends of polyamide and of polyolefin comprising a polyamide matrix, copolymers comprising polyamide blocks and polyether blocks, or blends of polyamides and of copolymers comprising polyamide blocks and polyether blocks, the inner layer (5) being in contact with the compressed air, wherein the polyamide of the outer layer (1) is chosen from:

PA11,

PA12,

a polyamide A corresponding to the formula X,Y/Z or 6,Y2/Z, in which:

X denotes the residues of an aliphatic diamine having from 6 to 10 carbon atoms,

Y denotes the residues of an aliphatic dicarboxylic acid having from 10 to 14 carbon atoms,

Y2 denotes the residues of an aliphatic dicarboxylic acid having from 15 to 20 carbon atoms,

Z denotes at least one unit chosen from the residues of a lactam, the residues of an α,ω-aminocarboxylic acid and the unit X1, Y1 in which X1 denotes the residues of an aliphatic diamine and Y1 denotes the residues of an aliphatic dicarboxylic acid,

the ratios by weight Z/(X+Y+Z) and Z/(6+Y2+Z) being between 0 and 15%, and

a semiaromatic polyamide B, and

wherein optionally at least one of the layers contains a product which facilitates adhesion to the adjacent layer.

3. The hose as claimed in claim 2 , wherein polyamide A of the outer layer is selected from the group consisting of PA 6,14, PA 6,18 and PA 10,10.

4. The hose as claimed in claim 2 , wherein polyamide B of the outer layer is selected from the group consisting of PA 6,116,T, PA 6,6/6,116,T, PA 6/6,T, PA 11/10,T, PA 12/12,T, PA 10,10/10,T and PA 10,I/10,T.

5. The hose as claimed in claim 2 , wherein at least one of the layers contains a product which facilitates adhesion to the adjacent layer.

6. The hose as claimed in claim 2 , wherein the inner layer (3) of the polymer having a flexural modulus of greater than 1100 MPa is replaced by three adjacent layers successively composed of a layer of polymer having a flexural modulus of greater than 1100 MPa, of a braid and of a layer of polymer having a flexural modulus of greater than 1100 MPa.

7. A multilayer hose for compressed air consisting of, in this order:

an outer layer (1) made of polyamide,

an inner layer (3) of a polymer having a flexural modulus of greater than 1100 MPa, the inner layer (3) being in contact with compressed air, wherein said inner layer polymer (3) is selected from the group consisting of polycarbonate (PC), polyphenyene sulfide (PPS), polyphenylene oxide (PPO) and a polyamide selected from the group consisting of PA 6, PA 6,6, PA 6,10, PA 6,12, an aromatic polyamide and a semiaromatic polyamide, or inner layer (3) optionally is replaced by three adjacent layers successively composed of a layer of polymer having a flexural modulus of greater than 1100 MPa, of a braid and of a layer of polymer having a flexural modulus of greater than 1100 MPa,

optionally a layer (4) of a polymer having a flexural modulus of less than 500 MPa, and

an inner layer (5) of a polymer chosen from polyamides, blends of polyamide and of polyolefin comprising a polyamide matrix, copolymers comprising polyamide blocks and polyether blocks, or blends of polyamides and of copolymers comprising polyamide blocks and polyether blocks, the inner layer (5) being in contact with the compressed air, wherein the polyamide of the outer layer (1) is chosen from:

PA11,

PA12,

a polyamide A corresponding to the formula X,Y/Z or 6,Y2/Z, in which:

X denotes the residues of an aliphatic diamine having from 6 to 10 carbon atoms,

Y denotes the residues of an aliphatic dicarboxylic acid having from 10 to 14 carbon atoms,

Y2 denotes the residues of an aliphatic dicarboxylic acid having from 15 to 20 carbon atoms,

Z denotes at least one unit chosen from the residues of a lactam, the residues of an α,ω-aminocarboxylic acid and the unit X1, Y1 in which X1 denotes the residues of an aliphatic diamine and Y1 denotes the residues of an aliphatic dicarboxylic acid, the ratios by weight Z/(X+Y+Z) and Z/(6+Y2+Z) being between 0 and 15%, and

a semiaromatic polyamide B, and

wherein optionally at least one of the layers contains a product which facilitates adhesion to the adjacent layer.

8. The hose as claimed in claim 7 , wherein polyamide A of the outer layer is selected from the group consisting of PA 6,14, PA 6,18 and PA 10,10.

9. The hose as claimed in claim 7 , wherein polyamide B of the outer layer is selected from the group consisting of PA 6,I/6,T, PA 6,6/6,I/6,T, PA 6/6,T, PA 11/10,T, PA 12/12,T, PA 10,10/10,T and PA 10,I/10,T.

10. The hose as claimed in claim 7 , wherein at least one of the layers comprises a product which facilitates adhesion to the adjacent layer.

11. The hose as claimed in claim 7 , wherein the inner layer (3) of the polymer having a flexural modulus of greater than 1100 MPa is replaced by three adjacent layers successively composed of a layer of polymer having a flexural modulus of greater than 1100 MPa, of a braid and of a layer of polymer having a flexural modulus of greater than 1100 MPa.