Sheet molding compound damper component, and methods for making and using the same

• US 20050095392A1
• Filed: 11/03/2003
• Published: 05/05/2005
• Est. Priority Date: 11/03/2003
• Status: Active Grant

• Current Assignee: Material Sciences Corporation (New Star Metals Holdings LLC)
• Original Assignee: Material Sciences Corporation (New Star Metals Holdings LLC)
• Inventors: Boss, Daniel
• Granted Patent: US 7,172,800 B2
• Time in Patent Office: Days
• US Class Current: 428/68
• CPC Class Codes: B32B 2262/101 Glass fibres
• CPC Class Codes: B32B 2307/542 Shear strength
• CPC Class Codes: B32B 25/08 of synthetic resin
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 7/022 Mechanical properties
• CPC Class Codes: Y10T 428/16 Two dimensionally sectional layer
• CPC Class Codes: Y10T 428/163 Next to unitary web or sheet of equal or greater extent
• CPC Class Codes: Y10T 428/23 Sheet including cover or casing
• CPC Class Codes: Y10T 428/239 Complete cover or casing
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/249946 Glass fiber
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/254 Polymeric or resinous material
• CPC Class Codes: Y10T 428/257 Iron oxide or aluminum oxide
• CPC Class Codes: Y10T 428/259 Silicic material
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31544 Addition polymer is perhalogenated
• CPC Class Codes: Y10T 428/31786 : Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31794 : Of cross-linked polyester
• CPC Class Codes: Y10T 428/31797 : Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31928 : Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31931 : Polyene monomer-containing
• CPC Class Codes: Y10T 428/31935 : Ester, halide or nitrile of addition polymer

Abstract

A damper component for absorbing and dissipating vibration and/or noise resonating from a device is provided. The damper component includes a viscoelastic damper layer, and a continuous constraining layer intimately contacting and encasing the damper layer. The constraining layer has a greater stiffness and higher modulus of dynamic shearing elasticity than the damper layer. The constraining layer is a molded sheet molding compound that is substantially immiscible with the viscoelastomer to provide a discrete interface between the constraining layer and the damper layer.

Claims

1. A damper component for absorbing and dissipating vibration and/or noise resonation, the damper component comprising:

a damper layer comprising a viscoelastomer; and

a continuous constraining layer intimately contacting and encasing the damper layer, the constraining layer having a greater stiffness and higher modulus of dynamic shearing elasticity than the damper layer, the constraining layer comprising a molded polyester sheet molding compound that is substantially immiscible with the viscoelastomer to provide a discrete interface between the constraining layer and the damper layer.

2. A damper component according to claim 1, wherein the viscoelastomer comprises a polymeric reaction product of a composition comprising a member selected from the group consisting of (meth)acrylic acid and (meth)acrylate.

3. A damper component according to claim 1, wherein the viscoelastomer comprises a polyacrylate.

4. A damper component according to claim 1, wherein the viscoelastomer comprises a member selected from the group consisting of nitrile rubbers and fluoroelastomers.

5. A damper component according to claim 1, wherein the damper layer is free of fillers.

6. A damper component according to claim 1, wherein the continuous constraining layer further comprises high density filler comprising a member selected from the group consisting of glass, carbon, aramids, metal, plastics, alumina, silica, silicon, ceramic, and graphite.

7. A damper component according to claim 1, wherein the continuous constraining layer further comprises chopped fiberglass.

8. A damper component according to claim 1, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least two orders of magnitude greater than that of the viscoelastic layer.

9. A damper component according to claim 1, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least three orders of magnitude greater than that of the viscoelastic layer.

10. A damper component according to claim 1, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least about 500,000 psi.

35. A method for retrofitting a device or structure that resonates vibration and/or noise, said method comprising:

removing an existing structural component of the device or structure through which the vibration and/or noise resonates; and

replacing the existing structural component with a damper component according to claim 1.

11. A damper component for absorbing and dissipating vibration and/or noise resonating from a device, the damper component comprising:

a fragmented damper layer comprising a plurality of fragments that are noncontinuous with each other to provide interstices between the noncontinuous fragments, the fragmented damper layer comprising a viscoelastomer; and

a continuous constraining layer intimately contacting and encasing the fragmented damper layer and filling the interstices between the noncontinuous fragments, the constraining layer having a greater stiffness and higher modulus of dynamic shearing elasticity than the fragmented damper layer, the constraining layer comprising a molded polyester sheet molding compound that is substantially immiscible with the viscoelastomer to provide discrete interfaces between the constraining layer and the noncontinuous fragments.

12. A damper component according to claim 11, wherein the viscoelastomer comprises a polymeric reaction product of a member selected from the group consisting of (meth)acrylic acid and (meth)acrylate.

13. A damper component according to claim 11, wherein the viscoelastomer comprises a polyacrylate.

14. A damper component according to claim 11, wherein the viscoelastomer comprises a member selected from the group consisting of nitrile rubbers and fluoroelastomers.

15. A damper component according to claim 11, wherein the fragmented damper layer is free of fillers.

16. A damper component according to claim 11, wherein the continuous constraining layer further comprises high density filler comprising a member selected from the group consisting of glass, carbon, aramids, metal, plastics, alumina, silica, silicon, ceramic, and graphite.

17. A damper component according to claim 11, wherein the continuous constraining layer further comprises chopped fiberglass.

18. A damper component according to claim 11, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least two orders of magnitude greater than that of the viscoelastic layer.

19. A damper component according to claim 11, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least two orders of magnitude greater than that of the viscoelastic layer.

20. A damper component according to claim 11, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least about 500,000 psi.

36. A method for retrofitting a device or structure that resonates vibration and/or noise, said method comprising:

removing an existing structural component of the device or structure through which the vibration and/or noise resonates; and

replacing the existing structural component with a damper component according to claim 11.

21. A method for making a damper component for absorbing and dissipating vibration and/or noise resonation, said method comprising:

providing a damper layer comprising a viscoelastomer;

arranging a melt-flowable, curable sheet molding compound adjacent the damper layer to form a laminate;

placing the damper layer and the melt-flowable, curable sheet molding compound in a mold cavity of a mold; and

heating the laminate under pressure in the mold to further cure the sheet molding compound to form a continuous constraining layer that intimately contacts and encases the damper layer, the constraining layer having a greater stiffness and higher modulus of dynamic shearing elasticity than the damper layer, the constraining layer comprising a cured polyester sheet molding compound that is substantially immiscible with the viscoelastomer to provide a discrete interface between the continuous constraining layer and the damper layer.

22. A method according to claim 21, wherein the viscoelastomer comprises a polymeric reaction product of a composition comprising a member selected from the group consisting of (meth)acrylic acid and (meth)acrylate.

23. A method according to claim 21, wherein the viscoelastomer comprises a polyacrylate.

24. A method according to claim 21, wherein the viscoelastomer comprises a member selected from the group consisting of nitrile rubbers and fluoroelastomers.

25. A method according to claim 21, wherein the damper layer is free of fillers.

26. A method according to claim 21, wherein the melt-flowable, curable sheet molding compound comprises a B-stage polyester.

27. A method according to claim 26, wherein the B-stage polyester comprises first and second sheets placed on opposite sides of the damper layer.

28. A method according to claim 27, wherein the first and second partially cured, sheet molding compound sheets comprise substantially identical compositions.

29. A method according to claim 27, wherein the first and second partially cured, sheet molding compound sheets comprise different compositions from one another.

30. A method according to claim 27, wherein said arranging comprising rolling the melt-flowable, curable sheet molding compound and the damper layer into a jelly roll, and wherein said placing comprises placing the jelly roll into the mold cavity.

31. A method according to claim 21, wherein the modulus of dynamic shearing elasticity of the continuous constraining layer is at least about 500,000 psi.

32. A method according to claim 21, wherein the continuous constraining layer further comprises high density filler comprising a member selected from the group consisting of glass, carbon, aramids, metal, plastics, alumina, silica, silicon, ceramic, and graphite.

33. A method according to claim 21, wherein the continuous constraining layer further comprises chopped fiberglass.

34. A hard disc drive assembly comprising:

a head disc assembly comprising a disc having a surface and a track for storage of information, a head for writing and reading information to and from the disc, and an actuator arm for moving the head relative to the surface of the disc; and

a housing comprising a base and a cover cooperating with one another to form a chamber therebetween in which at least a portion of the head disc assembly is housed, at least one of the base and the cover comprising a damper component for damping noise and/or vibration resonated by the head disc assembly, the damper component comprising

a viscoelastic damper layer; and

a continuous constraining layer intimately contacting and encasing the viscoelastic damper layer, the constraining layer having a greater stiffness and higher modulus of dynamic shearing elasticity than the viscoelastic damper layer, the constraining layer being molded from a high density filler and a melt-flowable polymer matrix that is immiscible with and not chemically bonded to the viscoelastic damper layer.