Process for the production of an acoustically resistive structure, the acoustically resistive structure thus obtained, and coating using such a structure

1. A process for the production of an acoustically resistive structure that can be inserted in an alveolar structure to obtain a coating for an acoustic treatment, said acoustically resistive structure ( 32 ) including at least one porous layer ( 34 ) and at least one reinforcement structure ( 36 ) assembled by gluing, the process comprising the steps of:

applying an amorphous-type adhesive on said at least one reinforcement structure ( 36 );

perforating or micro-perforating the reinforcement structure ( 36 ) after the application of the amorphous-type adhesive; and

applying said at least one porous layer against a face of the reinforcement structure ( 36 ) that is coated with the amorphous-type adhesive,

wherein, at peripheries of open zones of the acoustically resistive structure, said adhesive is not altered by a heating produced during the perforating step.

2. The process according to claim 1 , wherein the application of the porous layer ( 34 ) is carried out as a deposition piece by piece, whereby the amorphous-type adhesive is activated for each piece of the porous layer as the application of the porous layer proceeds.

3. The process according to claim 1 , wherein a thermostable adhesive is used.

4. The process according to claim 1 , wherein an amorphous-type adhesive film that is not adhesive under cold conditions is used.

5. The process according to claim 1 , further comprising the steps of:

arranging the reinforcement structure ( 36 ) and the film ( 40 ) on a mold ( 42 ) to form a unit, and subjecting the unit to a rise in temperature of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar; and

arranging the porous layer ( 34 ) and subjecting the unit to a temperature elevation of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar,

wherein the producing perforations or micro-perforations step is performed, after a cooling, upon the reinforcement structure and the adhesive layer.

6. An acoustically resistive structure insertable into an alveolar structure so as to obtain a coating for an acoustic treatment, whereby said acoustically resistive structure ( 32 ) comprises at least one porous layer ( 34 ) and at least one reinforcement structure ( 36 ) that are assembled with an amorphous-type adhesive from the process according to claim 1 .

7. A coating for the acoustic treatment that comprises, from an inside to an outside:

a reflective layer ( 28 );

at least one alveolar structure ( 30 ); and

an acoustically resistive structure ( 32 ),

wherein said acoustically resistive structure ( 32 ) comprises at least one porous layer ( 34 ) and at least one reinforcement structure ( 36 ) that are assembled with an amorphous-type adhesive from the process according to claim 1 .

8. A nacelle comprising:

a coating for an acoustic treatment that comprises, from the inside to the outside, a reflective layer ( 28 ), at least one alveolar structure ( 30 ), and an acoustically resistive structure ( 32 ),

wherein said acoustically resistive structure ( 32 ) comprises at least one porous layer ( 34 ) and at least one reinforcement structure ( 36 ) that are assembled with an amorphous-type adhesive from the process according to claim 1 .

9. The process according to claim 2 , wherein a thermostable adhesive is used.

10. The process according to claim 2 , wherein an amorphous-type adhesive film that is not adhesive under cold conditions is used.

11. The process according to claim 2 , further comprising the steps of:

arranging the reinforcement structure ( 36 ) and the film ( 40 ) on a mold ( 42 ) to form a unit, and subjecting the unit to a rise in temperature of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar; and

arranging the porous layer ( 34 ) and subjecting the unit to a temperature elevation of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar,

wherein the producing perforations or micro-perforations step is performed, after a cooling, upon the reinforcement structure and the adhesive layer.

12. The process according to claim 3 , further comprising the steps of:

arranging the reinforcement structure ( 36 ) and the film ( 40 ) on a mold ( 42 ) to form a unit, and subjecting the unit to a rise in temperature of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar; and

arranging the porous layer ( 34 ) and subjecting the unit to a temperature elevation of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar,

wherein the producing perforations or micro-perforations step is performed, after a cooling, upon the reinforcement structure and the adhesive layer.

13. The process according to claim 4 , further comprising the steps of:

arranging the reinforcement structure ( 36 ) and the film ( 40 ) on a mold ( 42 ) to form a unit, and subjecting the unit to a rise in temperature of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar; and

arranging the porous layer ( 34 ) and subjecting the unit to a temperature elevation of 100° C. to 300° C. so as to activate the adhesive, under a pressure of 1 to 15 bar,

wherein the producing perforations or micro-perforations step is performed, after a cooling, upon the reinforcement structure and the adhesive layer.