Polymeric materials, particularly elastomeric sheets, with a pressure sensitive adhesive laminated on at least one surface thereof have a great many industrial and consumer uses, including insulation, vibration damping and sound proofing. When cut into strips, the laminates find additional uses in sealing between surfaces in such uses as gaskets and weather stripping. One group of such polymeric materials referred to herein in order to describe and illustrate the present invention is elastomeric foams. Examples of elastomers are disclosed in U.S. Pat. No. 2,882,183 to Bond et al. and U.S. Pat. No. 4,169,184 to Pufahl, the disclosures of which are incorporated herein by reference.
The elastomeric sheets laminated with pressure sensitive adhesive are most useful when the pressure sensitive adhesive bonds to the elastomeric sheet with a greater bond strength than the pressure sensitive adhesive will bond to other substrates on which the laminate is applied. In other words, it is desired that when it is attempted to remove the elastomeric sheet from the substrate to which it has been applied with the pressure sensitive adhesive, the failure mode upon removal is preferably the cohesive failure of the elastomeric sheet and not the adhesive failure between the elastomeric sheet and pressure sensitive adhesive. This desired characteristic of elastomeric sheet/pressure sensitive adhesive laminates has not been achieved in the most part, particularly with respect to silicone foam elastomeric sheets and other elastomeric sheets on which it is difficult to obtain a satisfactory bond between the surface of the elastomeric sheet and the pressure sensitive adhesive. For example, U.S. Pat. No. 4,728,567 to Razzano, et al., incorporated herein by reference, discloses that a satisfactory bond strength between an acrylic pressure sensitive adhesive and a precured foamed silicone sheet cannot be obtained. Therefore, it is disclosed in this patent that the silicone foam should be cast on and cured in contact with the plastic or metal film or the pressure sensitive adhesive in order to obtain the desired bond strength between the pressure sensitive adhesive and the surface of the foam silicone foam sheet after it has cured.
However, it may be undesirable in some instances to be restricted to manufacturing the desired elastomeric sheet/pressure sensitive adhesive laminates by casting the uncured elastomer onto the pressure sensitive adhesive layer and curing the elastomer in place on the pressure sensitive adhesive layer. It is commercially desirable to use more conventional manufacturing methods which comprise using a pre-manufactured elastomeric sheet, which is supplied in roll form to a laminator. The laminator then feeds the elastomeric sheet from the roll to a laminating process together with a preformed pressure sensitive adhesive layer on a release paper, also supplied in roll form. The elastomeric sheet and pressure sensitive adhesive are laminated by rolling them between rollers, with some heat, if desired, to form the laminate of the elastomeric sheet and the pressure sensitive adhesive. Since the pressure sensitive adhesive layer has a release paper on one side of the pressure sensitive adhesive, the laminate thus formed can then be rolled up in a roll for future use. If desired, the sheet can be slit into strips before or after rolling in order to form individual reels of laminate strips. The laminate can then be used as a self-adhering tape by removing the release paper from the pressure sensitive adhesive side and applying the adhesive side of the laminate strip to the desired substrate surface.
Therefore, it is an object of this invention to provide desired elastomeric sheet/pressure sensitive adhesive laminates having the desired bond strength between the sheet and adhesive, as described above. It is a further object of this invention to provide such laminates which can be manufactured in conventional laminating processes.