초록

A multilayer composite material is formed of an acoustic core layer and at least one outer strengthening layer. The acoustic composite material has desirable high strength and high flexural modulus properties.

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1. A method of forming an acoustic composite material comprising the steps of: providing an acoustic core layer formed of a composite material comprising dehydrated reinforcing fibers and organic fibers, said organic fibers having one or more of varying lengths and varying dernier to tune the acoust

1. A method of forming an acoustic composite material comprising the steps of: providing an acoustic core layer formed of a composite material comprising dehydrated reinforcing fibers and organic fibers, said organic fibers having one or more of varying lengths and varying dernier to tune the acoustical behavior of said acoustic core layer to meet the needs of a desired application;providing two outer strengthening layers of glass fibers;positioning said acoustic core layer between said two outer strengthening layers;bonding said acoustic core layer to said outer strengthening layers to form an acoustic composite material; andsimultaneously with the step of forming an acoustic composite material, compressing said acoustic composite material to reduce said acoustic core layer to a uniform thickness, the acoustic composite material having a uniform weight, a uniform strength, and uniform acoustic properties. 2. The method of claim 1, wherein the step of providing the acoustic core layer-includes: removing water from wet reinforcing fibers to form dehydrated reinforcing fibers,blending the dehydrated reinforcing fibers with the organic fibers to form a substantially homogenous mixture of the dehydrated reinforcing fibers and the organic fibers, andforming the mixture into the acoustic core layer. 3. The method of claim 2, wherein the bonding step comprises: bonding together at least some of the dehydrated reinforcing fibers and the organic fibers in the acoustic core layer, andbonding the outer strengthening layers to the acoustic core layer. 4. The method of claim 3, further comprising the step of at least partially opening bales of wet reinforcing fibers prior to the removing step. 5. The method of claim 3, wherein the wet reinforcing fibers in the acoustic core layer are wet chopped strand glass fibers. 6. The method of claim 1, further comprising the step of attaching a facing layer to at least one exposed major surface of an outer strengthening layer. 7. The method of claim 1, wherein the acoustic core layer is bonded to the outer strengthening layers by applying heat to the acoustic core layer and outer strengthening layers. 8. The method of claim 1, wherein the outer strengthening layers comprise chopped strand mats. 9. The method of claim 1, wherein the outer strengthening layers have the same densities and thicknesses. 10. The method of claim 1, wherein the acoustic core layer has a basis weight within the range of from about 800 g/m2 to about 1400 g/m2, and the outer strengthening layers each have a basis weight within the range of from about 100 g/m2 to about 200 g/m2. 11. The method of claim 1, wherein during the step of compressing the acoustic composite material, the thickness of the acoustic core layer is reduced to about 7 percent of its thickness prior to being compressed. 12. The method of claim 1, wherein said acoustic core layer has a first stiffness and said acoustic composite material has a second stiffness, and wherein the second stiffness of said acoustic composite material is within the range of from about 17 percent to about 55 percent greater than the first stiffness of said acoustic core layer. 13. A method of forming an acoustic composite material comprising: positioning an acoustic core layer next to a major surface of at least one outer strengthening layer, said acoustic core layer being formed of a composite material comprising dehydrated reinforcing fibers and organic fibers;bonding said acoustic core layer to said at least one outer strengthening layer to form an acoustic composite material; andsimultaneously with the step of forming an acoustic composite material, compressing said acoustic composite material to reduce said acoustic core layer to a uniform thickness, said acoustic composite material having a uniform weight, a uniform strength, and uniform acoustic properties. 14. The method of claim 13, further comprising the step of forming the acoustic core layer prior to the positioning step, said forming step including: removing water from wet reinforcing fibers to form dehydrated reinforcing fibers,blending said dehydrated reinforcing fibers with said organic fibers to form a substantially homogenous mixture of said dehydrated reinforcing fibers and said organic fibers, andforming said mixture into said acoustic core layer. 15. The method of claim 14, wherein the bonding comprises: bonding together at least some of said dehydrated reinforcing fibers and said organic fibers in said acoustic core layer, andbonding said outer strengthening layers to said acoustic core layer. 16. The method of claim 15, wherein said outer strengthening layers comprise first and second outer strengthening layers and said first and second outer strengthening layers are applied to opposing surfaces of the acoustic core layer. 17. The method of claim 13, wherein said compression of said composite material occurs with said bonding. 18. The method of claim 13, wherein the acoustic core layer has a basis weight within the range of from about 800 g/m2 to about 1400 g/m2, and the outer strengthening layers each have a basis weight within the range of from about 100 g/m2 to about 200 g/m2. 19. The method of claim 13, wherein during the step of compressing the acoustic composite material, the thickness of the acoustic core layer is reduced to about 7 percent of its thickness prior to being compressed. 20. The method of claim 13, wherein said acoustic core layer has a first stiffness and said acoustic composite material has a second stiffness, and wherein the second stiffness of said acoustic composite material is within the range of from about 17 percent to about 55 percent greater than the first stiffness of said acoustic core layer. 21. A method of forming an acoustic composite material comprising: positioning an acoustic core layer next to a major surface of at least one outer strengthening layer, said acoustic core layer being formed of a composite material comprising dehydrated reinforcing fibers and organic fibers, said organic fibers having one or more of varying lengths and varying dernier to tune the acoustical behavior of said acoustic core layer to meet the needs of a desired application, andbonding said acoustic core layer to said outer strengthening layer to form an acoustic composite material; andsimultaneously with the step of forming an acoustic composite material, compressing said acoustic composite material to reduce said acoustic core layer to a uniform thickness, said acoustic composite material having a uniform weight, a uniform strength, and uniform acoustic properties. 22. The method of claim 21, further comprising the step of forming the acoustic core layer prior to the positioning step, the forming step including: removing water from wet reinforcing fibers to form dehydrated reinforcing fibers,blending said dehydrated reinforcing fibers with said organic fibers to form a substantially homogenous mixture of said dehydrated reinforcing fibers and said organic fibers, andforming said mixture into said acoustic core layer. 23. The method of claim 22, wherein said bonding step comprises: bonding together at least some of said dehydrated reinforcing fibers and said organic fibers in said acoustic core layer, and bonding said outer strengthening layers to said acoustic core layer. 24. The method of claim 22, wherein said wet reinforcing fibers are wet use chopped strand glass fibers. 25. The method of claim 21, further comprising: compressing said composite material to reduce said acoustic core to a desired thickness. 26. The method of claim 25, wherein said compression of said composite material occurs with said bonding. 27. The method of claim 21, wherein the acoustic core layer has a basis weight within the range of from about 800 g/m2 to about 1400 g/m2, and the outer strengthening layers each have a basis weight within the range of from about 100 g/m2 to about 200 g/m2. 28. The method of claim 21, wherein during the step of compressing the acoustic composite material, the thickness of the acoustic core layer is reduced to about 7 percent of its thickness prior to being compressed. 29. The method of claim 21, wherein said acoustic core layer has a first stiffness and said acoustic composite material has a second stiffness, and wherein the second stiffness of said acoustic composite material is within the range of from about 17 percent to about 55 percent greater than the first stiffness of said acoustic core layer. 30. A method of forming an acoustic composite material comprising the steps of: providing an acoustic core layer formed of a composite material comprising dehydrated reinforcing fibers and organic fibers, said acoustic core layer having a basis weight within the range of from about 800 g/m2 to about 1400 g/m2;providing two outer strengthening layers of glass fibers, said outer strengthening layers each having a basis weight within the range of from about 100 g/m2 to about 200 g/m2;positioning said acoustic core layer between said two outer strengthening layers;bonding said acoustic core layer to said outer strengthening layers to form an acoustic composite material; andcompressing said acoustic composite material to reduce said acoustic core layer to a uniform thickness, the acoustic composite material having a uniform weight, a uniform strength, and uniform acoustic properties. 31. A method of forming an acoustic composite material comprising the steps of: providing an acoustic core layer formed of a composite material comprising dehydrated reinforcing fibers and organic fibers, said organic fibers having one or more of varying lengths and varying dernier to tune the acoustical behavior of said acoustic core layer to meet the needs of a desired application, said acoustic core layer having a first stiffness;providing two outer strengthening layers of glass fibers;positioning said acoustic core layer between said two outer strengthening layers;bonding said acoustic core layer to said outer strengthening layers to form an acoustic composite material, said acoustic composite material having a second stiffness; andcompressing said acoustic composite material to reduce said acoustic core layer to a uniform thickness, the acoustic composite material having a uniform weight, a uniform strength, and uniform acoustic properties;wherein the second stiffness of said acoustic composite material is within the range of from about 17 percent to about 55 percent greater than the first stiffness of said acoustic core layer.