Coating processes – With post-treatment of coating or coating material – Heating or drying
Reexamination Certificate
1999-06-17
2001-09-18
Beck, Shrive P. (Department: 1762)
Coating processes
With post-treatment of coating or coating material
Heating or drying
C427S388100, C427S421100, C427S429000, C427S435000, C524S729000, C524S745000, C528S065000, C528S066000
Reexamination Certificate
active
06291019
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for damping vibration of a substrate and a composition therefor, and especially, although not exclusively to such a method and composition suitable for use in the automotive industry.
As the automobile has evolved, consumers have become continually more sophisticated and demanding. As such, they require many amenities, above and beyond excellent functionality For example, in luxury automobiles especially, the consumer expects a quiet ride. This feature is of such importance that automobile manufacturers frequently spend millions of dollars on advertising campaigns inundating the media with what a smooth, quiet and plush ride their particular automobiles have.
As such, the automotive industry, as well as the aerospace industry, railway the industries, and the truck and bus industry, have dedicated considerable research and development money to improving on a vehicle's noise, vibration and harshness (NVH) characteristics.
Many means have been attempted in order to solve the problem of vibration in a vehicle. One previous method of damping vibration included the placement of moldings and/or pads in appropriate areas. However, several drawbacks existed to this method in that the moldings and/or pads had to be very precisely precut in order to fit properly. Further, they required time consuming assembly to properly and securely attach the moldings/pads to the respective areas. Due to these drawbacks, the moldings and/or pads were nearly cost prohibitive in many cases.
Another solution was to spray epoxy or water born plastisols in liquid form onto (for example, in the automotive industry) a body in white. These sound damping compositions were sprayed wet and remained wet until they were cured. However, curing the plastisol on the body in white required heating. This resulted in several drawbacks, a few of which are that the plastisol composition would drip off and could contaminate the paint and/or E-coat system. Further, this composition could only go on the automotive body at a particular point in the assembly process, namely relatively soon before the body was to be put in the oven for baking (since the plastisol required heat for curing).
Accordingly, an object of the present invention is to provide a new and improved method for damping vibration of a substrate which does not require heating or other specialized process steps. It is a further object of the present invention to provide such a method which is simple and cost effective. It is yet a further object of the present invention to provide such a method which requires very little time in the assembly process and advantageously will not contaminate the vehicle paint or E-coat system. Still further, it is an object of the present invention to provide such a method which may be used at any point in the assembly process, eg. at the metal stamping stage up to and including the body in white stage, and either before or after the application of primer to the body in white.
It is also an object of the present invention to provide a composition which will damp vibration of a substrate, which composition advantageously cures substantially instantaneously in an ambient environment. Yet another object of the present invention is to provide such a composition which does not substantially release volatile organic materials.
SUMMARY OF THE INVENTION
The present invention addresses and solves the problems/drawbacks enumerated above, and encompasses other features and advantages as well. The present invention comprises a method for damping vibration of a substrate which comprises the step of applying a liquid material onto the substrate in an ambient environment, wherein, after application to the substrate, the material cures substantially instantaneously in the ambient environment.
A damping composition usable therefor comprises two components. The first component (ie. the resin component) consists essentially of a polymer and/or a blend of polymers present in an amount sufficient to impart a predetermined amount of tensile strength, hardness and flexibility; optionally, a chain extender and/or a blend of chain extenders present in an amount sufficient to impart a predetermined amount of tensile strength, weatherability, flexibility, adhesion to specific substrates, and hardness; and optionally, a filler and/or blend of fillers present in an amount sufficient to impart a predetermined amount of hardness, flexibility, and specific noise, vibration and harshness blocking characteristics to the after-application, cured surface.
The second component (ie. the isocyanate component) of the composition may consist essentially of isocyanate quasi-prepolymers based on a uretonimine modified MDI and a high molecular weight polyether polyol having an isocyanate equivalent content of 15.8% and a 2,4′-isomer content of less than about 15% . The second component may optionally also consist essentially of a plasticizer and/or a blend of plasticizers present in an amount sufficient to impart a predetermined amount of flexibility.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The method according to the present invention comprises the step of applying a liquid material onto the substrate in an ambient environment. It is to be understood that “ambient environment” as used herein may be the environment wherever the substrate is located and/or assembled, processed or otherwise manipulated, eg. an automotive assembly factory, an aeronautical factory, a stamping plant, etc.; and it is to be further understood that the present method and composition will achieve the stated objects and advantages in substantially any such “ambient environment.” However, it is preferred that the ambient temperature range between about 35° F. (1.7° C.) and about 160° F. (71.1° C.); it is more preferred that the ambient temperature range between about 50° F. (10° C.) and about 120° F. (48.9° C.); and it is most preferred that the ambient temperature range between about 70° F. (21.1° C.) and about 95° F. (35° C.). It is preferred that the ambient pressure range between about 730 mm Hg and about 800 mm Hg; however, it is more preferred that the ambient pressure range between about 750 mm Hg and about 780 mm Hg.
After application to the substrate, the liquid material cures substantially instantaneously on the substrate in the ambient environment. The curing time of the present invention preferably ranges between about 15 seconds and about 20 seconds, but can be as low as 2 seconds or as high as 30 minutes while still within the scope of the present invention and providing the advantages stated herein.
It is to be understood that the substrate may comprise any suitable substrate, including, but not limited to, metal stampings, bodies in white either before or after application of primer coat(s), carbon graphite composites, fiberglass, polycarbonates, ABS, and any other structural polymeric materials. As used herein, “body in white” is intended to mean a vehicle body assembled with all paintable components thereon, but without trim work or any other components which are not painted.
It is to be understood that the application step may comprise any suitable application means such as, for example, spraying, dipping, brushing, and it may be desired to utilize suitable hoods, ventilation means, and/or standard paint style spray booths. It is to be further understood that any of the application means may be performed either manually and/or automatically and/or robotically.
In a preferred embodiment, the application means is a conventional two component spray system, accommodating the first component and the second component of the composition of the present invention. In a more preferred embodiment, the application means is a high pressure, impingement mix spray system. One such suitable spray system is commercially available from GUSMER Corporation, and is described in a technical paper entitled, “The Processing of Spray Polyurea Elastomer Systems,” D. J. Primeaux II and K. C. Anglin, 34th Annual Polyureth
Irvine Daniel W.
Locke Ralph J.
Beck Shrive P.
Calcagni Jennifer
Mackinac Investors, LLC
Young & Basile P.C.
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