Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
This invention is directed to the lamination of a
protective backing on a mirror, with secure attachment of
the backing to the mirror, and to the mirror with that
5 backing secured thereto.
The glass normally used in the manufacture o
mirrors is subject to shattering when struck with an excess
of force~ In such shattering, a great number of glass
pieces of different shapes and sizes fall nearby, with the
10 distribution dependent upon the manner in which the breaking
force is applied, and other factors.
When transparency is required, as in ordinary
glass windows, not much can be done to restrain the pieces
when the glass is brvken. Nearly any attachment of
lS sufficient strength to restrain the glass pieces when a
window may be broken will adversely affect the transparency
of the window. Therefore, except for very special situations,
little is done with glass windows to control the shards
when a window is broken. However, since mirrors do-not
20 require the transmission of light ~herethrough, it is
possible to place a backing thereon which does not interfere
with the mirror properties, but will restrain the distribution
of glass shards should the mirror be broken. The process
for attaching a suitable restraining layer to the back of
25 a mirror is the purpose of this invention.
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3.~219'~B~
1 SUMMARY OF THE INVENTION
In order to aid in the understanding of this
invention, it can be stated in essentially summary form that
it is directed to a process for laminating upon a mirror a
5 protective ba,cking to control the shards of glass should the
mirror be broken. This invention is also directed to the
product resulting from the process.
The process comprises the steps of coating the
face of a paper layer with an adhesive and applying this face
10 against the back of a mirror with an open scrim of strong,
flexible fibers therebetween so that the paper is adhesively
attached both to the scrim and to the back of the mirror.
This retaining structure th'us has the strength in the scrim
and the attachment by the paper to pr,operly restrain broken
15 glass shards~
; It is, thus, an object of this invention to
provide a process by which a structure can be laminated to
the back of a mirror to restrain the broken glass shards upon
the breaking of the mirror. It is another object to provide
20 a process by which both a scrim and a layer of paper are
, adhesively attached to the back of the mirror so that they
,, cooperate to res~rain shards upon mirror breakage. It is a
: I
further object to provide a process whereby adhesive coating
over the entire face of a paper layer attaches both the paper
25 and the scrim to the back of a mirror. It is a further ob]ect
1 to prvvide a process for attaching a protective backing such
that it can be installed on a mirror production line 50
that the backing is attached as a part of the mirror
production sequence.
; The features of the present invention which are
believed to be novel are set forth with particularlity in the
appended claims. The present invention, both as to ltS
organization and manner of operation, together with further
objects and advantages thereof, may be best understood by
10 reference to the following description, taken in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic side-elevational view of
the arrangement of process equipment by which the process
15 for laminating a protec~ive backing onto the back of a
mirror is accomplished.
FIGURE 2 is an isometric view of the back of a
mirror, wlth the several layers partially broken away.
1, ' .
FIGURE 3 is an isometric view on larger scale
20 than FIGURE 2 of the mirror with the backing thereon, with
parts of the mirror and parts of the paper layer being
broken away.
~9 ~0
1 FIGU~E 4 is a side-elevational view oE a mirror
with the protective backing laminated thereon.
FIGURE 5 is an enlarged section through a portion
of the mirror, taken generally along the line 5-5 of FIGURE 4.
DESCRIPTION O~ THE PREFERRED EMBODIMENT
FIGURE 1 illustrates a group of process equipment 10
with which the process for laminating a protective backing on
the back of a mirror is accomplished. The process equipment 10
includes conveyor 12 by which mirrors are sequentially advanced
10 through the process steps. Conveyor 12 may be of any
convenient type suitable for handling mirrors. For example,
it may be a conveyor formed of rubber-faced rollers or
wheels which support and advance the mirrors. Conveyor 12
has a top plane 14 on which the mirrors are supported.
15 Most of the remainder of the conveyor 12 is purely schematic.
The conveyor is suitably powered so that the mirror is
moved through the process equipment in the desired manner.
Mirrors are sequentially fed along conveyor 12.
A stack of mirrors 16 is illustrated as the source of
20 mirrors. Individual mirrors are fed from the stack 16
onto the conveyor for advance. Mirror 18 is at the active
process stationb Mirrors 20 and 22 have passed from the
source through the active station and are on their way to
the next mirror step, which may be utilization. It is the
1 completed mirror 20 which is illustrated in more detail in
FIGURES 2 through 5.
While the source of mirrors is indicated as
being a stack 16, the mirrors on conveyor 12 may be received
directly $rom other mirror production machinery so that
they are delivered through the active station of the
processing equipment 10 as part of the continuous mirror
processing steps.
Two principal layers are adhered together on the
back of the mirror. Paper supply roll 24 supplies paper
web 26. Paper web 26 has a back 28 which is ultimately
the back of the completed assembly. The back surface 28
preferably carries thereon a layer of silicone to inhibit
sticking to other surfaces. The face 30 of paper web 26
is uncoated paper stock. The face 30 is coated with an
adhesive layer by coater 34. Coater 34 has suitable
;structure therein for applying adhesive layer 32. Adhesive
layer 32 is preferably a layer of hot melted adhesive and,
accordingly, coater 34 contains equipment for heating and
applying thermoplastic adhesive so as ~o form layer 32 on
the face 30 of paper web 26.
The paper web 26 is not sufficien~ly strong to
restrain shards of glass should the mirror be broken.
Scrim supply roll 36 supplies scrim web 38 for lamination
between paper web 26 and the reflectorized glass layer 40
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9~30
1 which forms the mirror. Scrim web 38 is preferably formed
of an open web of thermoplastic synthetic polymer composition
fibers which are thermoplastically bonded at their intersec-tions
by hot rolling. The scrim may be a fabric of loosely woven,
5 loosely knitted fibers, or formed of unwoven fibers.
In the preferred embodiment, scrim web 38 is loosely
woven, as is shown in FIGURE 3. After the weaving process,
the woven fabric is passed between hot rolls to both flatten
the fabric and provide bonding at the intersection of strands.
10 In the preferred embodiment indicated, scrim web 38 is laid
on the adhesive layered face of paper web 26. After laying
the two webs together and just before application to the mirror,
the assembly is heated as by radiant heater 42.
The assembly is laminated onto the back of mirror 18
lS by laying it onto the back of mirror 18 and passing the assembly
through pinch rolls 44 and 46. There is sufficient adhesive
material in adhesive coating layer 32 to completely cover the
backs of both the scrim web and the mirror. This coating is
assured by the action of the pinch rolls 44 and 46 where the
20 adhesive, in effect, is squeegeed at the pinch of the rolls to
completely coat the scrim and the mirror. In addition, the
i pinching action presses the scrim and the paper closely against
the back of the mirror so that the paper at the openings ln the
scrim is adhesively attached to the back of the mirror.
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3480
1 This is shown in FIGURES 2 and 3, where the adhesive is
shown as distributed across the entire mirror backing, and
in FIGURE 5, where it is illustrated as extending over the
scrim 38 as well as under the paper layer 26.
By the employment of a thermoplastic adhesive
and proper temperature control, the adhesive quickly sets at
the pinch rolls 44 and 46 due to the thermal mass provided
by the mirror 18. In this way, the paper web 26 is firmly
attached to the back of the scrim layer 38 and to the back
10 of the mirror where the scrim is open. The employment of a
thermoplastic adhesive is desirable because of the adhesive
attachment which is achieved promptly upon the squeezing
and squeegeeing action of the pinch rolls.
The resultant product has secure attachment of
15 the scrim because the paper secures the scrim in place.
This secure attachment thus securely restrains and retains
attachment to shards of glass when the mirror is broken.
The scrim provides the flexibility together with continuing
strength when the glass is broken, and the adhesive attachment
20 of the paper to the scrim and to the glass provides control
of the glass shards. In this way t the glass shards are
controlled to inhibit spreading of the parts when the mirror
is shattered.
1 This invention has been described in its presently
contemplated best mode~ and it is clear that it is susceptible
to numerous modifications, modes and embodiments within the
ability of those skilled in the art and without the exercise
5 of the inventive faculty. Accordingly, the scope of this
invention is defined by the scope of the following claims.
