Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-06-07
2003-09-02
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S211000, C528S018000
Reexamination Certificate
active
06613816
ABSTRACT:
This application relates to a cure on demand adhesive composition. The application further relates to a glass module having the cure on demand adhesive in an uncured state on a portion of the glass module. The application further relates to a process for bonding glass, such as window glass, to other substrates, such as buildings and automobiles.
Window glass is presently fixed into automobiles in the automobile assembly plants. A primer composition is applied to the window glass in the vicinity of where the adhesive is applied. A primer such as one disclosed in U.S. Pat. No. 5,115,086 or U.S. Pat. No. 5, 238,993 (both incorporated herein by reference) is applied to the window flange into which the glass is to be bonded. A bead of a polyurethane adhesive, such as disclosed in U.S. Pat. No. 4,758,648 and U.S. Pat. No. 4,780,520 (both incorporated herein by reference), is applied to the portion of the window to be contacted with the automobile window flange. The window is then placed in the window flange with the polyurethane adhesive composition between the glass and the automobile window flange. Typically the polyurethane adhesive cures upon exposure to moisture and after a period of time has sufficient strength to hold the window into the automobile under conditions of an impact at about 35 miles per hour.
This process is labor intensive requiring several steps in an automobile plant and requires the use of volatile chemicals in an automobile plant. To perform all of these operations in the vicinity of the assembly line requires a large amount of factory floor space.
It has been proposed to apply the primer and adhesive to the glass at a point remote from the automobile assembly line. U.S. Pat. No. 5,330,597 and U.S. Pat. No. 4,879,853 (both incorporated herein by reference) disclose methods for protecting the moisture curing polyurethane adhesive from exposure to atmospheric moisture curing. These approaches have not had commercial success as this requires removal of a protective layer strip from the adhesive in the automobile plant which requires additional time and complicates application.
World Patent 94/18255 discloses a storable modular construction element such as a storable glass module wherein a strip of a latent reactive adhesive is disposed around the periphery of the glass module. The latent reactive adhesive mainly contains one or more polyurethanes with blocked isocyanate groups, one or more polyurethane precursors constituted of polyols and/or polyamines encapsulated polyisocyanates or one or more polyurethanes with a radically polymerizable group. The adhesive disclosed in World Patent 94/18255 does not exhibit long term stability and rapid activation. Therefore, there has been no commercial utilization of this concept.
What is needed is a cure on demand adhesive which is stable when exposed to atmospheric conditions for up to five days, which contains a catalyst or curing agent which can be activated quickly, and preferably in less than 10 minutes, more preferably less than 3 minutes, has adequate green strength to hold a glass module into a substrate such as an automobile window without sagging, exhibits rapid enough cure such that a automobile into which such a window glass module is affixed, can be driven away in less than 3 hours from the time at which the window is affixed into the automobile, that the adhesive has sufficient strength after cure to meet the United States federal guidelines for bonding an automobile window into an automobile, and allows application of the adhesive remote from the automobile assembly plant. What is further needed is a window module with such a cure on demand adhesive placed thereon which meets such requirements. What is further needed is a process for bonding a window into a structure using such a cure on demand adhesive.
SUMMARY OF INVENTION
In one embodiment the invention is; an adhesive composition comprising
a) a polymer having a reactive moiety capable of cross-linking,
b) a particle comprising an active agent encapsulated in an encapsulating agent wherein the active agent comprises a catalyst for cross-linking of the reactive moiety, a curing agent for the reactive moiety, an accelerator for the curing reaction or a mixture thereof;
and the encapsulating agent comprises a thermoplastic or crystallizable polymer wherein the active agent is not substantially extractable from the particle at ambient conditions in an extraction after particle formation.
Preferably the crystalline or thermoplastic polymer has a transition point of from about 40° C. to about 250° C. and the active agent does not volatilize at conditions under which it is exposed during encapsulation.
An adhesive composition comprising an alkylene oxide based polymer having a reactive silicon moiety bound thereto and a silanol condensation catalyst encapsulated in an encapsulating agent having a transition point of from about 40° C. to about 250° C.
In yet another embodiment the invention is a process for binding two substrates together which comprises contacting one of the substrates with an adhesive as described herein, exposing the adhesive to conditions such that the active agent is released so as to contact the active agent with the polymer, contacting the two substrates such that the adhesive is located between the two substrates, and exposing the adhesive between the substrates to curing conditions. In a preferred embodiment of this process the adhesive is activated by exposure to an infrared heating source.
In yet another embodiment the invention is window module useful in an automobile comprising
a substrate which is useful as a window which has applied to the portion of the window which is to be bound into a structure an uncured adhesive as described herein. In another embodiment the invention is a process for mounting a window into a structure which comprises a) applying an adhesive as described herein in the form of a profiled strip about the periphery of one face of a window in a location remote from the location wherein the window is to be placed in the substrate, wherein the adhesive is in an uncured or partially uncured state; b) transporting the window with the adhesive strip applied thereto to the location where the window is to be mounted into the structure; c) performing an operation upon the adhesive to activate curing of the adhesive; d) mounting the window into the structure such that the adhesive contacts the window and substrate; e) allowing the adhesive to cure such that the window is bonded into the substrate.
The cure on demand adhesive of the invention exhibits sufficient stability when exposed to atmospheric conditions such that it will not cure for a period of up to 5 days or more. Furthermore, the adhesive of the invention can be activated relatively quickly and preferably within 10 minutes or less and more preferably within 3 minutes or less. The cured adhesive bond exhibits a tensile strength upon cure of about 250 psi (1.72 mPa) or greater, preferably about 400 psi (2.76 mPa) and most preferably about 500 psi (3.45 mPa). The adhesive of the invention demonstrates adequate green strength to hold the window into an automobile window frame or building structure without sagging. Further the adhesive of the invention demonstrates rapid cure in that the adhesive cures sufficiently such that an automobile into which a window is affixed with such adhesive can be driven within about 3 hours after mounting the window into the automobile. The adhesive of the invention has sufficient tensile strength and elongation properties to meet the United States Motor Vehicle Safety guidelines relative to bonding of windshields in automobiles. Furthermore, window module with the adhesive applied thereto exhibits all of the aforementioned properties.
DETAILED DESCRIPTION OF THE INVENTION
The adhesive composition of the invention contains a polymer having a reactive moiety capable of cross-linking. The polymer can be any polymer known to those skilled in the art with reactive moieties which can be cured and which can be used as an adhesive. Prefer
Hoffman Dwight K.
Hsieh Harry W.
Lin Renhe R.
Mahdi Syed Z.
Parker Gordon M.
Moore Margaret G.
Parker Michael
Sims Norman L
The Dow Chemical Company
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