Process for the preparation of a vehicle window

The invention is a process for preparing a prefabricated vehicle window comprising the sequential steps of: PA0 (a) placing a cover film in a receptacle to provide a film cavity, with a portion of the cover film extending out of the receptacle, wherein the cavity is of a dimension sufficient to hold a bead of adhesive which would extend around the entire periphery of the window; PA0 (b) depositing a bead of an uncured, deformable adhesive in the cavity on top of the cover film in an amount sufficient to slightly overfill the cavity; and PA0 (c) contacting the bead of adhesive with a vehicle window under conditions sufficient to press adhesive out of the cavity and between the vehicle window and the portion of the cover film extending over the sides of the receptacle such that the adhesive pressed out of the cavity bonds the film to the window along the edges of the bead of adhesive.

BACKGROUND OF THE INVENTION 
This invention relates to the mounting or installation of vehicle windows 
and, more specifically to vehicle windows which are mounted or installed 
through the use of an adhesive. 
It is known to mount vehicle windows in a vehicle through the use of an 
adhesive such as, for example, a moisture-curable urethane adhesive. In 
such a mounting procedure, the edge of the window is glued to a flange of 
a vehicle body. In such procedures, however, it is usually necessary to 
apply the moisture-curable adhesive to the window just prior to the 
mounting of the window, since exposure to atmospheric moisture prior to 
mounting will, over a period of time, cause the adhesive to cure and lose 
its ability to bond effectively to the vehicle flange. However, if the 
adhesive is applied just prior to mounting of the window, the vehicle 
manufacturer must purchase, operate, and maintain a substantial amount of 
pumping and dispensing equipment, as well as store substantial quantities 
of the moisture-curable adhesive. In addition, in the case of automotive 
windshields, the vehicle manufacturer may also need to maintain a full 
line of pumping and dispensing equipment to apply one or more glass 
primers (usually a clear primer followed by a wiping operation, followed 
by the application of a "blackout" primer) to the glass surface prior to 
the application of the moisture-curable adhesive. 
It is also known to pre-apply moisture curable adhesive to a window, and 
then cover the adhesive with moisture-proof foil in such a manner that the 
foil does not touch the bead of adhesive. The air enclosed in the foil is 
then evacuated and the package is filled with a dry protection gas. Upon 
application, the foil is completely removed to expose the uncured 
adhesive, as described in U.S. Pat. No. 4,879,853. 
U.S. Pat. No. 4,879,853 also describes a process for pre-applying moisture 
curable adhesive to a window by first preparing a cured bead of adhesive 
adhered to the window in the shape of a receptacle for a second bead of 
uncured adhesive, placing a bead of moisture-curable adhesive in the 
receptacle which does not completely fill the receptacle, and then placing 
a covering over the receptacle which does not touch the uncured bead of 
adhesive. Upon application, the foil is completely removed from the 
receptacle to expose the uncured adhesive. 
It would be desirable to develop a process for the pre-application of a 
moisture curable adhesive which does not require the use of protection 
gases or the removal of the cover foil during application, nor require the 
vehicle manufacturer to maintain a full line of pumping and dispensing 
equipment and a supply of adhesive and primers.

SUMMARY OF THE INVENTION 
In one aspect, this invention is a process for preparing a prefabricated 
vehicle window comprising the sequential steps of: 
(a) placing a cover film in a receptacle to provide a film cavity, with a 
portion of the cover film extending out of the receptacle; 
(b) depositing a bead of an uncured, deformable adhesive in the cavity on 
top of the cover film in an amount sufficient to slightly overfill the 
cavity; 
(c) contacting the bead of adhesive with a vehicle window under conditions 
sufficient to press adhesive out of the cavity and between the vehicle 
window and the portion of the cover film extending over the sides of the 
receptacle such that the adhesive pressed out of the cavity bonds the film 
to the window along the edges of the bead of adhesive. 
In a second aspect, this invention is a prefabricated vehicle window 
comprising 
a vehicle window; and 
a substantially uncured, deformable bead of moisture-curable adhesive 
material extending along the periphery of the vehicle 
wherein the bead of adhesive is covered by, and substantially in contact 
with, a cover film which is adhesively secured to the vehicle window along 
the inboard and outboard edges of the bead of adhesive. 
It has been discovered that the process of the invention provides a 
prefabricated vehicle window which does not require in its manufacture the 
use of a preformed adhesive receptacle adhered to the glassy nor the use of 
dry gases to prevent the adhesive from curing before it is applied to the 
vehicle flange. The vehicle window may be manufactured in a location 
remote from where it is to be installed in a vehicle, and does not require 
the vehicle manufacturer to maintain a full line of pumping and dispensing 
equipment and a supply of adhesive and primers. 
DETAILED DESCRIPTION OF THE INVENTION 
Suitable cover films for use in the process of the invention include any 
film which has a sufficiently low permeability to water vapor to prevent 
the exterior portion of a moisture-curable adhesive (the portion which 
would normally be exposed to air after deposition onto the vehicle window) 
contained in such film from curing or "skinning over" within about 
twenty-four hours of the completion of the process for making the 
prefabricated vehicle window. Preferably, the film has a sufficiently low 
permeability to water vapor to prevent such curing for at least about 7 
days following the completion of the process for making the prefabricated 
vehicle window. Preferably, the film has a permeability to water vapor of 
less than about 300 g/100 in.sup.2 /h/ml at 39.5.degree. C., more 
preferably less than about 50 g/100 in.sup.2 /h/ml at 39.5.degree. C. Such 
films are also preferably thick and/or strong enough to not rupture during 
the process, but are thin and/or flexible enough to enable the film to 
conform to the dimensions of the cavity used in the process. Preferably, 
such films have a thickness in the range of from at least about 0.1 mil, 
more preferably at least about 0.5 mil; to no greater than about 10 mils, 
and more preferably no greater than about 1 mil. Preferably, the film has 
a tensile strength which is sufficient to prevent tearing of the film 
during the process for preparing the prefabricated vehicle window of the 
invention, and during handling of the window during storage and shipment, 
but may be cut easily to expose the adhesive without removing the film. 
The cover film may be comprised of several individual layers of film, 
which may also contain a metallized film layer to improve moisture barrier 
properties. Examples of such films include poly(vinylidene chloride) films, 
and polyester/metal laminate films, both available as Saran.TM. films from 
The Dow Chemical Company, and polyester films available from Courtauldes 
and Cadillac Plastics. 
Suitable receptacles for holding the film include any receptacle which will 
provide, upon the insertion of a film, a film cavity with sufficient 
structural integrity to hold a bead of adhesive during the process for 
preparing the vehicle window of the invention. Preferably, the receptacle 
is constructed from a substantially rigid metal or molded plastic, and is 
part of a mold apparatus wherein the receptacle portion is shaped 
length-wise to match the periphery of the vehicle window, having 
dimensions which define the size and configuration of an adhesive bead to 
be applied to the vehicle window. The cover film may be placed in the 
cavity by any suitable meanst in order to line the shaped cavity with the 
cover film such that the cover film extends out of the cavity. In 
addition, the receptacle also preferably contains perforations which are 
connected to a vacuum and/or gas pressure system. Such a system is 
preferably arranged so that when a vacuum is applied on the outside of the 
receptacle to the perforations, the cover film placed in the cavity will 
assume the shape of the receptacle. Such a system may also be arranged so 
that when the film cavity is filled with adhesive and air pressure is 
applied on the outside of the receptacle to the perforations, the film 
containing the adhesive may be more easily removed from the receptacle. 
The film cavity may be of any suitable size or linear dimension sufficient 
to hold a bead of adhesive sufficient in size to bond the vehicle window 
to a vehicle window flange. Preferably, the film cavity is of a dimension 
sufficient to hold a bead of adhesive which would extend around the entire 
periphery of the window. The cross-section of the film cavity may also be 
of any suitable shapes but is preferably substantially "V"-shaped as shown 
in FIG. 3 or "U"-shaped, as shown in FIG. 4, since such a shape has been 
discovered to allow the film to be more easily placed in the cavity near 
and around window corners. The bead of adhesive may be deposited in the 
cavity by any suitable means, such as adhesive extruders or dispensers 
commonly used in the application of urethane adhesives for vehicle window 
bonding applications and is preferably deposited in a nitrogen atmosphere 
to prevent the moisture curing of the adhesive. Preferably, the extrusion 
nozzle is preferably shaped as shown in FIG. 5. The bead of adhesive must 
be large enough to slightly overfill the cavity, and form a surface of 
exposed adhesive. By "slightly overfill," it is meant that there is 
sufficient adhesive in the cavity so that when the adhesive in the cavity 
is contacted with the vehicle window and the cavity and window are pressed 
towards each other, enough of the adhesive will be displaced out of the 
cavity between the vehicle window and the portion of the cover film 
extending over the sides of the receptacle, to effectively bond that 
portion of cover film to the vehicle window along the inboard and outboard 
edges of the bead of adhesive. Preferably, the bead of adhesive is also 
large enough to provide sufficient adhesion between the glass and a metal 
substrate, such as a window flange, after application of the vehicle 
window to the flange and curing of the adhesive. The bead of adhesive is 
preferably extruded in a roughly triangular shape or a "U" shaper with the 
height of the bead, and the width of the bead at the top of the receptacle 
in the range of from about 5 mm to about 5 cm, more preferably in the 
range of from about 14 to about 18 mm. 
Suitable adhesives for use in the preparation of the prefabricated vehicle 
window of the invention include any moisture-curable adhesive which will 
effectively bond a vehicle window to a window flange. Preferably, the 
adhesive is a one-part urethane adhesive with excess isocyanate groups, 
which will cure in the presence of atmospheric moisture. Most preferably, 
the adhesive is a "fast cure"-type adhesive, prepared from a urethane 
prepolymer having an isocyanate functionality between 2.3 and 3.0 and a 
catalyst comprising either dimorpholinodiethyl ether or a mixture of 
organic tin and organic bismuth, as described in U.S. Pat. Nos. 4,758,648 
and 4,284,751, which are hereby incorporated by reference in their 
entirety. 
The adhesive in the prefabricated vehicle window of the invention is 
substantially uncured. By "substantially uncured," it is meant that the 
adhesive has not cured to the point at which it will no longer bond 
effectively with a metal window flange upon removal or cutting of the 
adhesive film and installation of the window. 
The vehicle window may be of any suitable size or dimension, and may be 
comprised of any suitable material, such as glass or a polymeric material, 
such as polycarbonate. Preferably, the window is comprised of glass. In 
addition, the window also preferably has a layer of black ceramic coating 
along the edge of the window on the surface which is to be bonded to the 
flange, for styling or cosmetic reasons. It may also be preferable to 
apply a layer of a silane glass primer or "wipe," and/or a layer of a 
glass primer, which is preferably black, along the edge of the window on 
the surface which is to he bonded to the flange, to promote the adhesion 
of the window to the flange, and/or, in the case of a black primer, to 
provide protection from ultraviolet rays for the adhesive if an adhesive 
which needs such protection is used. 
To contact the vehicle window with the bead of adhesive, the window may be 
placed on top of the receptacle holding the film and adhesive with enough 
force applied to press a portion of the adhesive overfill out of the film 
cavity and between the vehicle window and the portion of the cover film 
extending over the sides of the receptacle, to effectively bond that 
portion of cover film to the vehicle window along the inboard and outboard 
edges of the bead of adhesive. 
The bead of adhesive is contacted with the vehicle window soon enough after 
its deposition in the cavity so that the bead is substantially uncured. 
Preferably, the bead of adhesive is substantially in contact with the 
cover film so that there is no air or moisture trapped between the film 
and uncured adhesive which would cause the adhesive to cure past the point 
where it is no longer substantially uncured and deformable. 
In its second aspect, this invention is a prefabricated vehicle window 
comprising 
a vehicle window; and 
a substantially uncured, deformable bead of a moisture-curable adhesive 
material extending along the periphery of the vehicle window; 
wherein the bead of adhesive is covered by, and substantially in contact 
with, a cover film which is adhesively secured to the vehicle window along 
the inboard and outboard edges of the bead of adhesive. 
The prefabricated vehicle window of this aspect of the invention may be 
prepared by the process of the invention, as described above. 
If a seal and/or decorative molding along the edge of the window is 
desired, such molding may be prefabricated separately in its desired shape 
and glued to the vehicle window, or may be fabricated by depositing a 
separate bead of hardenable adhesive material in the shape of the desired 
molding onto the vehicle window and allowing the bead to harden. Such a 
fabrication process occurs before the window is contacted with the bead of 
adhesive described in step (c) of the process of the invention. If the bead 
is fabricated from a bead of hardenable adhesive, the bead is deposited so 
that it partially extends over the edge of the vehicle window, as shown in 
FIG. 3, and may be positioned so that a portion of it is between the window 
and the layer of substantially uncured adhesive. In such a case, it is not 
necessary for the film which covers the uncured adhesive to be bonded to 
the vehicle window along the inboard and outboard sides of the bead of 
adhesive as described above in step (c) of the process of the invention, 
if it is effectively bonded to the hardened adhesive material to keep the 
uncured adhesive bead substantially uncured. The hardened bead also 
preferably has a substantially planar surface for contacting with the 
uncured bead of adhesive. Such a seal and/or molding will advantageously 
help prevent water from entering any gaps between the glass edge and the 
rabbet (the surface adjacent to the vehicle flange, which is roughly 
parallel to the edge of the glass, which connects the vehicle flange to 
the remainder of the vehicle frame), which would otherwise freeze in cold 
climates and exert a force on the glass edge. However, the molding, which 
is preferably flexible, is primarily a styling or cosmetic feature of the 
glass assembly which covers any gaps between the glass edge and rabbet. 
The bead of hardenable adhesive material may comprise any substance which 
will form an elastomeric polymer bonded to the window upon curing, and 
able to bond with the bead of adhesive to be deposited on top of the 
polymer such as described, for example in U.S. Pat. No. 4,571,278, the 
relevant portions of which are hereby incorporated by reference. 
Preferably, the material is comprised of the same adhesive as the bead of 
adhesive which is to be deposited on top of the polymer. The bead of 
hardenable adhesive material is deposited on the window by any suitable 
means, such as extrusion, and is cured to form an elastomeric polymer by 
any suitable method, such as by exposure to atmospheric moisture or steam, 
prior to the deposition of the uncured bead of adhesive on top of the 
elastomeric polymer. 
When the prefabricated vehicle window is to be bonded to the vehicle flange 
(that is, to the substrate which forms the vehicle window opening), it will 
be necessary to cut or remove the film in order to allow the adhesive to 
come into contact with the flange. For example, the film may be removed 
manually by pulling it off, although this method would be more 
labor-intensive than other possible methods (since the film is bonded to 
the glass) and therefore less desirable. This method is also less 
desirable since a portion of the uncured adhesive may cling to the film 
during removal of the film. The adhesive may also be exposed by manually 
or robotically cutting the film lengthwise, approximately along the middle 
of the bead of adhesive. The adhesive would then be placed against the 
flange, and the adhesive would be allowed to cure. Another method for 
"cutting" the film would be to place a wire along the bottom of the film 
cavity during the process for making the window, at least one end of which 
is kept outside the cover film, which could be pulled in a direction 
perpendicular to the glass along the adhesive bead to cut the film. When 
the film is cut to expose the adhesive, the film need not be otherwise 
removed from the window. The vehicle window may be contacted with the 
vehicle window flange by any suitable means, such as manually, or by 
robotic means. 
Referring now to the drawings, FIG. 1 illustrates one embodiment of the 
prefabricated vehicle window of the invention. Vehicle window 1 is shown, 
with a layer of film 2 covering the bead of adhesive. FIG. 2 shows a cross 
section of the same window, including the bead of adhesive 3 which is 
covered by the film 2. FIG. 3 shows a cross section of a vehicle window 
prepared with a layer of an elastomeric polymer with a substantially 
planar top surface 4 between the vehicle window surface and the bead of 
adhesive. This elastomeric polymer provides a decorative rim around the 
edge of the window, and/or serves as a seal and/or reveal molding between 
the edge of the glass and the vehicle window opening after the vehicle 
window is installed. FIGS. 4(a), (b), and (c) illustrate an embodiment of 
the process of the invention and more clearly illustrates the interface 
between the bead and the film. FIG. 4(a) shows a cross section of a cover 
film 2 placed in a receptacle 5. FIG. 4(b) shows a cross section of a bead 
of adhesive 3 deposited in the cavity. FIG. 4(c) shows a cross section of 
the bead of adhesive contacted with a vehicle window. FIG. 5 illustrates a 
preferred nozzle for depositing a bead of adhesive in the process of the 
invention. The triangular cut-out portions on the side of the nozzle allow 
a tall bead of adhesive to be extruded inside the receptacle. 
ILLUSTRATIVE EMBODIMENTS 
The following examples are given to illustrate the invention and should not 
be interpreted as limiting it in any way. 
EXAMPLE 1 
A cover film (a polyvinylidene chloride film, sold as Saranex.TM. SX-14 by 
The Dow Chemical Company) is placed in a receptacle as shown in FIG. 4(a). 
A bead of a moisture-curable urethane adhesive (sold as 58702 by Essex 
Specialty Products, Inc.) is deposited in the receptacle as shown in FIG. 
4(b). A windshield is then placed on top of the receptacle as shown in 
FIG. 4(c). The windshield is then removed from the receptacle. The 
windshield will have attached to its periphery the bead of adhesive 
covered by the cover film which is secured to the windshield along the 
inboard and outboard edges of the bead of adhesive. When the windshield is 
to be installed, the cover film is cut to expose at least a portion of the 
Dead of adhesive along the entire periphery of the windshield, and the 
side of the windshield with the exposed bead of adhesive is placed against 
the flange surrounding the vehicle window opening. The adhesive is then 
allowed to cure. 
EXAMPLE 2 
Window Molding Example 
A Dead of hardenable adhesive is extruded along the periphery of a 
windshield, so that a portion of it extends over the edge of the 
windshield, and is cured to form a hardened bead of adhesive with a 
substantially planar top surface which extends over the edge of the 
windshield, as shown by numeral (4) in FIG. 3. In a separate operation, a 
cover film (a polyvinylidene chloride film, sold as Saranex.TM. SX-14 by 
The Dow Chemical Company) is placed in a receptacle as shown in FIG. 4(a). 
A bead of a moisture-curable urethane adhesive (sold as 58702 by Essex 
Specialty Products, Inc.) is deposited in the receptacle as shown in FIG. 
4(b). The windshield with the hardened bead of adhesive described above is 
then placed on top of the receptacle as shown in FIG. 4(c), so that the 
bead of uncured adhesive will be superpositioned on the portion of the 
hardened bead which is in contact with the windshield when the windshield 
is removed from the receptacle. The windshield is then removed from the 
receptacle. The windshield will have attached to its periphery the bead of 
adhesive covered by the cover film which is secured to the windshield or 
and/or the hardened bead of adhesive along the inboard and outboard edges 
of the uncured bead of adhesive. When the windshield is to be installed, 
the cover film is cut to expose at least a portion of the bead of adhesive 
along the entire periphery of the windshield, and the side of the 
windshield with the exposed bead of adhesive is placed against the flange 
surrounding the vehicle window opening and is positioned so that the 
molding substantially covers the gap between the edge of the glass and the 
vehicle rabbet. The adhesive is then allowed to cure.