Sound insulating structure
The present invention addresses the problem of providing a sound insulating structure which provides a sufficient sound insulating effect even when an adhesive layer is arranged therein, and in which a shift in the frequency band where the sound insulating effect is generated is unlikely to occur. This sound insulating structure includes, at least: a sound insulating member that includes a sheet-like sheet section and plural projections arranged on the sheet section; and an adhesive layer arranged on a surface of the sheet section on the opposite side of the side provided with the projections, and the sound insulating structure satisfies the following Formula (1): E_glue/I_glue>0.5×(E_membrane/H) (1) (wherein, E_glue (MPa): storage modulus of adhesive layer, I_glue (mm): average thickness of adhesive layer, E_membrane (MPa): storage modulus of sheet section and projections, and H (mm): average height of sheet section and projections).
1. A sound insulating structure, comprising, at least:
a sound insulating member that comprises a sheet-like sheet section and plural projections arranged on one side of the sheet section; and
an adhesive layer arranged on a surface of the sheet section on the opposite side of the side provided with the projections, and
an adherend to which the sound insulating member is adhered via the adhesive layer,
wherein
a storage modulus of the adherend is not less than 500 MPa,
the adherend includes:
at least one selected from the group consisting of polyacetal (POM), polyamide (PA), polycarbonate (PC), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), ultrahigh-molecular-weight polyethylene (UHPE), syndiotactic polystyrene (SPS), amorphous polyarylate (PAR), polysulfone (PSF), polyether sulfone (PES), polyphenylene sulfide (PPS), polyether ketone (PEEK), polyimide (PI), polyether imide (PEI), fluororesins (fluorocarbon polymers), and liquid crystal polymers (LCP), and/or
at least one metal selected from the group consisting of aluminum, iron, stainless steel and alloys thereof,
the sound insulating structure satisfies the following Formula (1):
E _glue/ I _glue>0.5×( E _membrane/ H ) (1)
E_glue (MPa): storage modulus of adhesive layer
I_glue (mm): average thickness of adhesive layer
E_membrane (MPa): storage modulus of sheet section and projections
H (mm): average height of sheet section and projections, and
the E glue (MPa) of the storage modulus of adhesive layer and the E membrane (MPa) of storage modulus of sheet section and projections are measured in a measurement atmosphere having a temperature of 23° C. and a humidity of 50% RH.
2. The sound insulating structure according to claim 1 ,
wherein an amount of normalized natural frequency shift satisfying the following formula is 0 to 30%:
Amount of normalized natural frequency shift (%)=((Design natural frequency)−(Natural frequency))÷(Design natural frequency)
Design natural frequency (Hz): natural frequency determined in a condition without adhesive layer
Natural frequency (Hz): natural frequency determined in a condition with adhesive layer.
3. The sound insulating structure according to claim 1 ,
wherein the adhesive layer has an elastic modulus of more than 10 MPa.
4. The sound insulating structure according to claim 1 , satisfying the following Formulae (2) and (3):
7,000 ≥E _glue/ E _membrane≥0.5 (2)
50.0 ≥E _glue/ E _adh≥0.00002 (3)
E_glue (MPa): storage modulus of adhesive layer
E_membrane (MPa): storage modulus of sheet section and projections
E_adh (MPa): storage modulus of adherend.
5. The sound insulating structure according to claim 1 , satisfying the following Formula (4):
1.0≥ I _glue≥0.005 (4)
I_glue (mm): average thickness of adhesive layer.
6. The sound insulating structure according to claim 1 , wherein Formula (1) satisfies the following Formula (1)′:
E _glue/ I _glue>β×( E _membrane/ H ) (1)′
wherein, E_glue, I_glue, E_membrane, and H have the same meanings as in Formula (1), and β=5.
7. The sound insulating structure according to claim 1 , wherein the E_glue is more than 10 MPa.
8. The sound insulating structure according to claim 1 , wherein
the adhesive layer comprises one or more resins selected from the group consisting of silicone resins, epoxy resins, and cyanoacrylate resins, and
a total content ratio of these resins in the adhesive layer is 10% by weight or more.
9. The sound insulating structure according to claim 1 , wherein
the adhesive layer comprises an inorganic filler, and
a content ratio of the inorganic filler in the adhesive layer is 1% by weight or more.
10. A method of producing the sound insulating structure according to claim 1 ,
the method comprises:
forming the sound insulating member having plural projections on the one side of the sheet section; and
arranging the adhesive layer on the sound insulating member, and
arranging the adherend to which the sound insulating member is adhered via the adhesive layer.
11. The sound insulating structure according to claim 1 , wherein the adherend is not a part of another sound insulating member.
12. The sound insulating structure according to claim 1 , wherein the adhesive layer adheres to a product or component to be sound-insulated.
13. The sound insulating structure according to claim 1 , wherein the adhesive layer comprises silicone resin.
14. The sound insulating structure according to claim 1 , wherein the adhesive layer comprises cyanoacrylate resin.
15. The sound insulating structure according to claim 1 , wherein the adherend includes polyacetal (POM).
16. The sound insulating structure according to claim 1 , wherein the adherend includes polyamide (PA).
17. The sound insulating structure according to claim 1 , wherein the adherend includes polycarbonate (PC).
18. The sound insulating structure according to claim 1 , wherein the adherend includes modified polyphenylene ether (m-PPE).