Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
1999-10-21
2003-05-20
Seidleck, James J. (Department: 1711)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S347000, C428S195100, C428S200000, C428S3550EP, C428S356000
Reexamination Certificate
active
06565969
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an adhesive article having a pressure sensitive adhesive layer and a bondable layer as well as to an assembly comprising the adhesive article.
BACKGROUND OF THE INVENTION
The individual benefits of pressure sensitive adhesives and other types of adhesives, including structural adhesives, are well known. There are also applications where two types of adhesives have been combined to realize the benefit of both types of adhesives.
U.S. Pat. No. 5,593,759 discloses a pressure sensitive structural adhesive material comprising a core layer of a thermally curable structural adhesive providing opposed surfaces having on at least one surface thereof a separate continuous or discontinuous layer of a tacky pressure sensitive adhesive, the pressure sensitive adhesive being absorbed into the core layer upon curing.
Japanese Kokai Patent No. 3-14888 discloses a heat curable tacky adhesive sheet with a heat curing area and pressure sensitive adhesive area on the same face of the sheet, in which both the heat curing area and the pressure sensitive area are continuous through the thickness of the film or are both coated, side-by-side, on a supporting film.
U.S. Pat. No. 4,908,273 discloses a multilayer, heat curable adhesive film having a tacky external heat curable layer and a dry external heat curable layer, containing adducts which contain epoxide groups.
EP 942054 discloses an assembly comprising two substrates bonded together by an adhesive system comprising at least one pressure sensitive adhesive layer and at least one cured structural hybrid adhesive layer wherein at least one of the pressure sensitive adhesive layers is essentially continuous and extends essentially over the full width of the bonded area.
U.S. Pat. No. 5,086,088 discloses a pressure-sensitive thermosetting adhesive comprising a blend of an acrylic ester and an epoxy resin.
The industry continues to seek adhesive articles having a combination of benefits of different types of adhesives, for example, both pressure sensitive adhesive and structural adhesive characteristics.
In addition, the industry continues to seek adhesive articles that simultaneously afford excellent shelf stability, including retention of pressure sensitive adhesive characteristics, for example, tack, and excellent adhesive properties over a wide temperature range after bonding, including preferably retention of lap shear and peel strength at elevated temperature, good impact strength at room temperature and at lower temperatures, for example, −40° C., resistance to creep under load, and ability to retain properties after environmental exposure. The industry also seek adhesive articles having a lack of sensitivity to moisture exposure during storage.
SUMMARY OF THE INVENTION
The present invention relates to an adhesive article comprising a bondable layer and a pressure sensitive adhesive layer on at least one major surface of the bondable layer, as well as an assembly comprising one or more substrates and the adhesive article.
The adhesive article of the present invention may have one or more features as described herein.
For example, a pressure sensitive adhesive layer may be continuous over at least one major surface of the bondable layer or a pressure sensitive layer may be discontinuous over at least one major surface of the bondable layer. A pressure sensitive adhesive layer preferably retains its pressure sensitive adhesive characteristics, as described herein.
A bondable layer may be a thermosetting material, a thermoplastic material, or a hybrid material as defined below. A thermosetting or hybrid bondable layer, when tested alone after bonding, may have an overlap shear strength as tested in accordance with ASTM D-1002-94, at room temperature (approximately 23° C.±3° C.) of at least about 6.9 MegaPascals (“MPa”), and preferably at a temperature from room temperature up to and including about 80° C. of at least about 6.9 MPa.
An adhesive article of the present invention having a thermosetting or hybrid bondable layer, which has been bonded, may also have an overlap shear strength as tested in accordance with ASTM D-1002-94, at room temperature (approximately 23° C.±3° C.) of at least about 6.9 MPa, and preferably at a temperature from room temperature up to and including about 80° C. of at least about 6.9 MPa.
An adhesive article of the present invention having a thermoplastic bondable layer, after bonding, may have an overlap shear of at least 1 MPa, more preferably more than 2 MPa, in accordance with ASTM D-1002-94, at room temperature (approximately 23° C.±3° C.).
In one embodiment, the present invention relates to an adhesive article comprising a bondable layer having on at least one major surface a discontinuous layer of pressure sensitive adhesive, wherein the bondable layer comprises a thermosetting material, the pressure sensitive adhesive layer substantially retains pressure sensitive adhesive characteristics after storage at room temperature for at least about three months prior to bonding the adhesive article, and the adhesive article has a overlap shear measured at room temperature according to ASTM D-1002-94 of at least about 6.9 MPa after bonding.
In another embodiment, the present invention relates to an adhesive article comprising a bondable layer having on at least one major surface a discontinuous layer of pressure sensitive adhesive, wherein the bondable layer comprises a thermoplastic material.
In yet another embodiment, the present invention relates to an adhesive article comprising a bondable layer having on at least one major surface a discontinuous layer of pressure sensitive adhesive, wherein the bondable layer comprises a thermosetting material selected from the group consisting of urethanes, cyanate esters, phenolics, and bismaleimides, and any combinations thereof.
In yet another embodiment, the present invention relates to an adhesive article comprising a bondable layer having on at least one major surface a discontinuous layer of pressure sensitive adhesive, wherein the bondable layer comprises a fusible epoxide prepolymer which is a solid at room temperature.
The present invention also relates to an adhesive article comprising a bondable layer having on at least one major surface a discontinuous layer of pressure sensitive adhesive, wherein the bondable layer comprises a hybrid material and the pressure sensitive adhesive substantially retains pressure sensitive adhesive characteristics after storage at room temperature for at least about three months prior to bonding the adhesive article.
In another embodiment, the present invention relates to an adhesive article comprising a bondable layer having on at least one major surface a continuous layer of pressure sensitive adhesive, wherein the bondable layer comprises a thermosetting material, the pressure sensitive adhesive layer substantially retains pressure sensitive adhesive characteristics after storage at room temperature for at least about three months prior to bonding the adhesive article.
The present invention also relates to an assembly comprising a substrate and an adhesive article as described herein, wherein the substrate is in contact with the pressure sensitive adhesive layer of the adhesive article.
The present invention also relates to a method of making an adhesive article. One method comprises (a) selecting a bondable material, (b) forming a bondable layer, (c) selecting a pressure sensitive adhesive that substantially retains pressure sensitive adhesive characteristics when in contact with the bondable layer after storage at room temperature for at least about three months prior to bonding the adhesive article, and (d) providing a discontinuous layer of the pressure sensitive adhesive on a major surface of the bondable layer, wherein the adhesive article has a overlap shear measured at room temperature according to ASTM D-1002-94 of at least about 6.9 MPa after bonding.
Another method comprises (a) selecting a bondable material, (b) forming a bondable layer, (c) selecti
Bolitsky Robert E.
Jung Dieter
Klingen Juergen
Lamon Alain Henri
Noe Susan C.
3M Innovative Properties Company
Bissett Melanie
Pastirik Daniel R.
Seidleck James J.
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