Reinforcement laminate

Abstract

A thermosettable adhesive is used to secure a laminate having a compliant layer (for example, a foamable composition containing a diene rubber), a layer comprised of a thermosettable resin capable of being cured to a rigid state, and an optional carrier layer (for example, a metal foil) to a substrate for the purpose of strengthening, stiffening, or otherwise reinforcing the substrate. The substrate may, for example, be a metal vehicle door. The thermosettable adhesive is comprised of at least one polyol such as a polyether polyol, at least one epoxy resin, and at least one polyisocyanate.

Description

BACKGROUND OF THE INVENTIONIn a number of applications, light-weight, high strength structural members are required. For example, in motor vehicles and aircraft as well as in various devices such as home appliances and the like, a number of composite materials have been proposed in the past as structural members, such as exotic light-weight alloys. In most applications, however, mass reduction must be balanced against the cost of the product to the consumer. Thus, there is a need for providing strength without significantly increasing material and labor costs. Moreover, reinforcement techniques are needed which can be easily adapted to existing geometries of structural parts, thereby obviating any requirement for fundamental design changes.It would be desirable to provide a structural member which may be generally considered as a wall with some form of reinforcement. While such forms of reinforcement could have numerous applications, it would be particularly desirable to provide suc...

AI Technical Summary

Benefits of technology

A laminate useful for reinforcing or stiffening body panels is provided which includes three polymeric layers. One of the polymeric layers is a compliant layer comprised of flexible, pliable polymer which is adhered to the substrate or structural member being reinforced using a reactive thermosettable adhesive comprised of at least one polyol, at least one epoxy resin, and at least one polyisocyanate. Thermosettable adhesives of this type have been found to provide a high strength bond between the laminate and the substrate, even where the substrate surface is coated with oil or other greasy substanes. A rigid layer comprised of a thermoset resin is secured to the other side of the compliant layer. The rigid layer improves the resistance of the substance against bending or flexing. A carrier, such as a foil or fiberglass backing, may be secured to the outer surface of the rigid layer. The laminates of the present invention have the further advantage of dampening acoustic and other vibrations, thereby reducing the level of noise in the interior of a vehicle having panels reinforced with such laminates.

Problems solved by technology

Although the oil-canning may be momentary with the panel immediately returning to its original configuration, it may be permanent and, moreover, may cause a crease to form in the panel coating.

Although filling large volumes of a door cavity with a foam could prevent oil-canning, such an approach would also significantly increase mass and thus weight, which, of course, is an undesirable feature.

In addition, large volumes of foam contribute significantly to cost.

Finally, a large foam core often creates an unwanted heat sink.

And, although increasing the metal gauge of the door panel or adding localized thick metal reinforcements will increase stiffness, as the metal thickness increases weight increases.

When the vehicle doors are painted, there often is a problem with paint read-through once the outer metal body panel stiffened with the thermoset polymer sheet has been heat cured.

That is, the painted outer surface of the vehicle door becomes somewhat distorted as a result of the shrinkage of the thermoset polymer which takes place upon curing, thereby marring the appearance of the painted door.

This is often difficult to achieve in practice, however, as the surfaces of such body panels tend to be coated with oil or other substances which interfere with adhesion.

Although the body panel surface can be degreased through the use of solvents or the like, this introduces an additional step to the production process and creates waste (i.e., used solvent or oily rags) which must then be disposed of.

Images