U.S. patent application number 09/726845 was filed with the patent office on 2001-03-29 for method of repairing scratched and/or abraded transparent substrates and the repaired substrates.
Invention is credited to Everaerts, Albert I., Janssen, Jeffrey R., O'Keefe, Donald R., Sheffield, William F..
Application Number | 20010000076 09/726845 |
Document ID | / |
Family ID | 22664654 |
Filed Date | 2001-03-29 |
United States Patent
Application |
20010000076 |
Kind Code |
A1 |
Janssen, Jeffrey R. ; et
al. |
March 29, 2001 |
Method of repairing scratched and/or abraded transparent substrates
and the repaired substrates
Abstract
The present invention relates to scratches and/or abraded first
substrates such as windows that have been repaired using a bonding
material and a second undamaged substrate. Repaired articles and
method of repair are provided.
Inventors: |
Janssen, Jeffrey R.;
(Woodbury, MN) ; Everaerts, Albert I.; (Oakdale,
MN) ; O'Keefe, Donald R.; (Roseville, MN) ;
Sheffield, William F.; (Oakdale, MN) |
Correspondence
Address: |
Office of Intellectual Property Counsel
3M Innovative Properties Company
PO Box 33427
St. Paul
MN
55133-3427
US
|
Family ID: |
22664654 |
Appl. No.: |
09/726845 |
Filed: |
November 30, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09726845 |
Nov 30, 2000 |
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09181525 |
Oct 28, 1998 |
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6180245 |
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Current U.S.
Class: |
428/426 |
Current CPC
Class: |
B29K 2995/0026 20130101;
Y10T 428/31623 20150401; B29C 73/04 20130101; B29C 2073/262
20130101; Y10T 428/31634 20150401; Y10T 428/24364 20150115; Y10T
428/31507 20150401; B32B 17/10963 20130101 |
Class at
Publication: |
428/426 |
International
Class: |
B32B 017/06 |
Claims
It is claimed:
1. An article comprising: a laminate comprising: (a) a first
substrate, the first substrate having a first major surface and an
opposite second major surface, wherein the first substrate
comprises a material selected from the group consisting of glass,
plastic and combinations thereof, wherein the first substrate has
at least one scratch on its first major surface and wherein the
first major surface of the first substrate has an R.sub.max of
greater than about 1 micron; (b) a second substrate having a first
major surface and an opposite second major surface wherein the
second substrate comprises immediately before, during and after
formation of the laminate a material selected from the group
consisting of glass, amorphous plastic in its glassy state,
amorphous plastic in its rubbery state, crystalline plastic in its
glassy state, crystalline plastic in its rubbery state, and
combinations thereof; (c) a bonding material layer positioned
between the first substrate and the second substrate in a manner to
form a laminate, wherein the bonding material layer at least
partially rills the scratch(es) and is in contact with at least the
abraded area of the first major surface of the first substrate and
is in contact with at least a portion of the second major surface
of the second substrate; wherein a maximum haze value through the
laminate is less than about 20 percent.
2. The article of claim 1 wherein the article when subjected to a
visual acuity test using a 3 meter Snellen eye chart can allow an
observer with 6 meter/6 meter vision to read a line on the eye
chart which is indicative of about 6 meter/9 meter vision or
better.
3. The article of claim 1 wherein the bonding material layer
completely fills the scratch(es) in the first substrate.
4. The article of claim 1 wherein the maximum haze value through
the laminate is less than about 10 percent.
5. An article comprising: a laminate comprising: (a) a first
substrate, the first substrate having a first major surface and an
opposite second major surface, wherein the first substrate is
selected from the group consisting of glass, plastic and
combinations thereof; wherein the first substrate has an abraded
and/or scratched area on its first major surface and wherein the
first major surface of the first substrate has a maximum haze
value; (b) a second substrate having a first major surface and an
opposite second major surface, wherein the second substrate
comprises, immediately before, during, and after formation of the
laminate, a material selected from the group consisting of glass,
amorphous plastic in its glassy state, amorphous plastic in its
rubbery state, crystalline plastic in its glassy state, crystalline
plastic in its rubbery state, and combinations thereof; (c) a
bonding material layer positioned between the first substrate and
the second substrate in a manner to form a laminate, wherein the
bonding material is in contact with at least the abraded area of
the first major surface of the first substrate and is in contact
with at least a portion of the second major surface of the second
substrate; wherein a maximum haze value through the laminate is
less than about 20 percent; and wherein the maximum haze value
through the laminate is less than the maximum haze value of the
first substrate.
6. The article of claim 5 wherein the maximum haze value through
the laminate is less than about 10 percent.
7. A method comprising: (a) providing a first substrate, the first
substrate having a first major surface and an opposite second major
surface, wherein the first substrate is selected from the group
consisting of glass, plastic and combinations thereof, wherein the
first substrate has at least one scratch on its first major surface
and wherein the first major surface of the first substrate has an
R.sub.max; (b) abrading the first major surface of the first
substrate over at least one scratch to provide an abraded area of
the first major surface of the first substrate such that the first
major surface of the first substrate has an R.sub.max which is less
than that of step (a), wherein if the abrasion itself does not
remove any visible contaminants on the first major surface of the
first substrate, the first major surface of the first substrate is
cleaned to remove any visible contaminants; (c) forming a laminate
comprising (i) the first substrate, (ii) a second substrate having
a first major surface and an opposite second major surface, wherein
the second substrate comprises immediately before, during and after
the formation of the laminate a material selected from the group
consisting of glass, amorphous plastic in its glassy state,
amorphous plastic in its rubbery state, crystalline plastic in its
glassy state, crystalline plastic in its rubbery state and
combinations thereof, and (iii) a bonding material layer, wherein
the bonding material layer is positioned between the first
substrate layer and the second substrate layer, wherein the bonding
material layer is in contact with at least the abraded area of the
first major surface of the first substrate and is in contact with
at least a portion of the second major surface of the second
substrate; wherein a maximum haze value through the laminate is
less than about 20 percent.
8. The method of claim 7 wherein at least a portion of the bonding
material layer which is brought into contact with the abraded area
of the first substrate upon forming the laminate has a stress
relaxation value of about 15 to about 100 percent when measured at
a temperature at which the laminate is formed.
9. The method of claim 7 wherein the bonding material is selected
from the group consisting of viscous liquids, viscoelastic solids,
and mixtures thereof.
10. The method of claim 7 wherein the bonding material is selected
from the group consisting of polyacrylics, silicones, polyolefins,
rubber, polymers and mixtures thereof.
11. The method of claim 7 wherein step (c) comprises the steps of
(i) providing a layer of bonding material over the abraded area of
the first substrate wherein the bonding material having a stress
relaxation value of at least about 15% at a temperature at which
the laminate is formed; and (ii) placing the second substrate over
the coating in order to form a laminate.
12. The method of claim 7 wherein step (c) comprises the steps of
(I) providing a construction comprising (i) the second substrate;
(ii) the layer of bonding material having a stress relaxation value
of at least about 15% at a temperature at which the laminate is
formed coated on said second substrate; (II) laminating together
the construction and the first substrate in a manner such that the
bonding material layer having a stress relaxation value of at least
about 15 % is in contact with at least the abraded area of the
first major surface of the first substrate.
13. The method of claim 7 wherein step (c) comprises the steps of
(I) providing a construction comprising (i) the second substrate;
and (ii) the bonding material layer having a stress relaxation
value of less than about 15% at a temperature at which the laminate
is formed coated on at least a portion of the second major surface
of said second substrate; (II) causing the bonding material layer
of (l) (ii) to change such that its stress relaxation value becomes
at least about 15% at a temperature at which the laminate is
formed; (III) laminating together the construction and the first
substrate in a manner such that the bonding material layer having a
stress relaxation value of at least about 15% is in contact with at
least the abraded area of the first surface of the first major
surface.
14. The method of claim 7 wherein the R.sub.max of the first major
surface of the first substrate in step (a) is at least about 40
microns to about 500 microns.
15. The method of claim 7 wherein the R.sub.max of the first major
surface of the first substrate in step (b) is about 15 microns or
less.
16. The method of claim 7 wherein the first substrate is a glass
window.
17. A method comprising: (a) providing a first substrate, the first
substrate having a first major surface and an opposite second major
surface, wherein the first substrate is selected from the group
consisting of glass, plastic and combinations thereof, wherein the
first substrate has at least one scratch on its first major surface
and wherein the first major surface of the first substrate has an
R.sub.max greater than about 1 micron; (b) removing any visible
contaminants on the first major surface of the first substrate by
cleaning; (c) forming a laminate comprising (i) the first
substrate, (ii) a second substrate having a first major surface and
an opposite second major surface, wherein the second substrate
comprises immediately before, during and after formation of the
laminate a material selected from the group consisting of glass,
amorphous plastic in its glassy state, amorphous plastic in its
rubbery state, crystalline plastic in its glassy state, crystalline
plastic in its rubbery state and combinations thereof, and (iii) a
bonding material layer positioned between the first substrate layer
and the second substrate layer, wherein the bonding material layer
is in contact with at least the abraded area of the first major
surface of the first substrate and is in contact with at least a
portion of the second major surface of the second substrate layer;
wherein a maximum haze value through the laminate is less than
about 20 percent.
18. The article of claim 5 wherein the first substrate in (b) has a
maximum haze value of about 20 or greater.
19. The method of claim 7 wherein the first substrate has of the
abrading a maximum haze value of about 20 or greater.
20. The article of claim 1 wherein the first substrate has a
Scratch Visibility Test rating of 1-2 and the laminate has a
Scratch Visibility Test rating of 0-1.
Description
FIELD OF THE INVENTION
1. This invention relates to a method of repairing one or both
sides of an optically damaged substrate such as rigid glass or
plastic window, signage or displays. The invention also relates to
the repaired substrates.
BACKGROUND OF THE INVENTION
2. Windows and glass in public transportation vehicles such as
buses or subway trains can be subjected to a tremendous amount of
abuse. The windows can be damaged by both incidental scratching
during cleaning or they can be maliciously damaged by vandalism.
Vandals damage the windows by scratching or abrading the surface of
the window with items such as lava rock, diamonds, abrasive papers
or abrasive cloths. Vandals can also damage the window by painting
or coloring the surface of the window. Cleaning processes have been
defined to eliminate damage by painting or coloring. However,
scratching of glass by vandals presents a significant problem. In
one major city for example, approximately 40 percent of the bus
windows have been vandalized by scratching and close to 80 percent
of the subway train windows. The public transportation officials
now call this type of graffiti "scratchiti". The best approach to
stopping graffiti historically has been is to remove the graffiti
immediately from the damaged area. This graffiti prevention system
which is known as "zero tolerance", has been extremely successful
in eliminating the written and painted vandalism. The scratched
glass however is extremely difficult and expensive to repair and as
a result, the zero tolerance approach to scratchiti prevention and
elimination is cost prohibitive. The vandalism issue tarnishes the
overall image of an entire city's transportation system. The
vandalized glass leads to lower ridership because of the reduced
perception of safety on the vehicle by the public. The vandalism
ultimately leads to lost revenue for the public transportation
system and substantially high repair costs. A cost effective method
of restoring the window to its original appearance is needed.
3. Several approaches have been evaluated to restore the windows to
its original appearance. The first approach has been to repair the
glass by a multi-step abrasion/polishing method to remove the
scrachiti. The abrasion steps remove glass to the depth of the
scratch with diamond abrasives and then with subsequently finer
grades of diamond or aluminum oxide abrasives the surface of the
glass is polished to its original appearance. The abrasive
materials are expensive and the time required to completely abrade
and polish the surface of the glass can be 6-8 hours depending on
the depth of the damaged areas.
4. The second approach commonly used to repair and protect windows
from scratches is to coat the damaged window with an epoxy coating
(Enhancement of Vehicle Glazing for Vandal Resistance and
Durability by Daniel R. Bowman, Mar. 25, 1996, available from the
United States Transportation Research Board). The damaged window is
typically first scrubbed clean before coating with an epoxy
coating. The epoxy coating is used to fill the defects on the
windows and restore the window to a state of clarity where signs
can be read through the window. To apply the coating, the window
must be removed from the vehicle and the window must be cleaned and
primed. The coatings are applied and cured in a clean environment.
The coatings currently available however are easily scratched by
the same method used to scratch the glass. Once the coating is
damaged, it is difficult to apply a subsequent coating due to poor
adhesion of the coating to the first layer. The process to replace
the damaged coating with a new coating is time consuming and
expensive.
5. U.S. Pat. No. 4,301,193 disclosed a method of removing scratches
and impregnated dirt from transparent plastic article by applying a
polishing formulation containing a mild abrasive to a surface to be
treated, polishing the surface with a soft material and applying to
the polished surface a liquid silicone formulation and wiping the
surface with dry soft material.
6. U.S. Pat. No. 5,194,293 disclosed a method for restoring
weathered plastic surfaces and for enhancing resistance of the
treated surface to sunlight by cleaning the surface, polishing with
a mild abrasive, applying a first layer of an uncured adhesive
material that is ultraviolet curable and applying an outer coat of
a compatible curable adhesive over the uncured to form a
semi-permanent outer surface on the article. Curing is initiated by
exposure to ultraviolet radiation.
7. GB 2310862 disclosed a resin formulation for repairing a
transparent glass member e.g. an automobile windscreen. The fluid
resin is injected into a crack, which mixes with the trapped air in
the damaged area. A device withdraws the fluid resin and trapped
air, separates resin and trapped air and reinject separated resin
in the cracked area. Repeated injections are possible because the
resin has a select viscosity.
8. U.S. Pat. No. 5,512,116 disclosed a method of repairing an
automobile windscreen by inserting a first resin of selected
viscosity into the surface portions of the crack and then inserting
a second resin of selected viscosity which is higher than the first
into the remainder of the crack.
SUMMARY OF THE INVENTION
9. The present invention provides fast, cost effective methods of
restoring the optical clarity (i.e. decreasing the maximum haze and
visible scratches) of a first substrate such as a window or
glazing, for example. Also provided are the restored substrates.
The article of the invention comprises a first substrate which has
been scratched and/or abraded. On top of the first substrate is a
bonding layer and a second substrate. The second substrate is
typically a pre-made plastic or glass material that forms a
protective surface and a rejuvenated surface to the damaged first
substrate. The bonding layer typically flows into damaged areas of
the first substrate eliminating light diffusion due to the damaged
areas of the glass.
10. The present invention provides an article comprising:
11. a laminate comprising:
12. (a) a first substrate, the first substrate having a first major
surface and an opposite second major surface, wherein the first
substrate comprises a material selected from the group consisting
of glass, plastic and combinations thereof, wherein the first
substrate has at least one scratch on its first major surface and
wherein the first major surface of the first substrate has an
R.sub.max of greater than about 1 micron;
13. (b) a second substrate having a first major surface and an
opposite second major surface wherein the second substrate
comprises immediately before, during and after formation of the
laminate a material selected from the group consisting of glass,
amorphous plastic in its glassy state, amorphous plastic in its
rubbery state, crystalline plastic in its glassy state, crystalline
plastic in its rubbery state, and combinations thereof;
14. (c) a bonding material layer positioned between the first
substrate and the second substrate in a manner to form a laminate,
wherein the bonding material layer at least partially fills the
scratch(es) and is in contact with at least the abraded area of the
first major surface of the first substrate and is in contact with
at least a portion of the second major surface of the second
substrate;
15. wherein a maximum haze value through the laminate is less than
about 20 percent.
16. In a preferred embodiment the article when subjected to a
visual acuity test using a 3 meter Snellen eye chart can allow an
observer with 6 meter/6 meter vision to read a line on the eye
chart which is indicative of about 6 meter/9 meter vision or
better.
17. In a preferred embodiment the bonding material layer completely
fills the scratch(es) in the first substrate.
18. In a preferred embodiment the maximum haze value through the
laminate is less than about 10 percent, more preferably less than
about 5 percent, and most preferably less than about 3 percent.
19. The present invention provides an article comprising:
20. a laminate comprising:
21. (a) a first substrate, the first substrate having a first major
surface and an opposite second major surface, wherein the first
substrate is selected from the group consisting of glass, plastic
and combinations thereof;
22. (b) wherein the first substrate has an abraded and/or scratched
area on its first major surface and wherein the first major surface
of the first substrate has a maximum haze value;
23. (b) a second substrate having a first major surface and an
opposite second major surface, wherein the second substrate
comprises, immediately before, during, and after formation of the
laminate, a material selected from the group consisting of glass,
amorphous plastic in its glassy state, amorphous plastic in its
rubbery state, crystalline plastic in its glassy state, crystalline
plastic in its rubbery state, and combinations thereof;
24. (c) a bonding material layer positioned between the first
substrate and the second substrate in a manner to form a laminate,
wherein the bonding material is in contact with at least the
abraded area of the first major surface of the first substrate and
is in contact with at least a portion of the second major surface
of the second substrate;
25. wherein a maximum haze value through the laminate is less than
about 20 percent; and wherein the maximum haze value through the
laminate is less than the maximum haze value of the first
substrate.
26. Preferably the maximum haze value through the laminate is less
than about 10 percent, more preferably less than about 5 percent,
and most preferably less than about 3 percent.
27. The present invention also provides a method comprising:
28. (a) providing a first substrate, the first substrate having a
first major surface and an opposite second major surface, wherein
the first substrate is selected from the group consisting of glass,
plastic and combinations thereof, wherein the first substrate has
at least one scratch on its first major surface and wherein the
first major surface of the first substrate has an R.sub.max;
29. (b) abrading the first major surface of the first substrate
over at least one scratch to provide an abraded area of the first
major surface of the first substrate such that the first major
surface of the first substrate has an R.sub.max which is less than
that of step (a), wherein if the abrasion itself does not remove
any visible contaminants on the first major surface of the first
substrate, the first major surface of the first substrate is
cleaned to remove any visible contaminants;
30. (c) forming a laminate comprising (i) the first substrate, (ii)
a second substrate having a first major surface and an opposite
second major surface, wherein the second substrate comprises
immediately before, during and after the formation of the laminate
a material selected from the group consisting of glass, amorphous
plastic in its glassy state, amorphous plastic in its rubbery
state, crystalline plastic in its glassy state, crystalline plastic
in its rubbery state and combinations thereof, and (iii) a bonding
material layer, wherein the bonding material layer is positioned
between the first substrate layer and the second substrate layer,
wherein the bonding material layer is in contact with at least the
abraded area of the first major surface of the first substrate and
is in contact with at least a portion of the second major surface
of the second substrate;
31. wherein a maximum haze value through the laminate is less than
about 20 percent.
32. In a preferred embodiment of the method at least a portion of
the bonding material layer which is brought into contact with the
abraded area of the first substrate upon forming the laminate has a
stress relaxation value of about 15 to about 100 percent when
measured at a temperature at which the laminate is formed.
33. In a more preferred embodiment of the method at least a portion
of the bonding material layer which is brought into contact with
the abraded area of the first substrate upon forming the laminate
has a stress relaxation value of about 20 to about 90 percent when
measured at a temperature at which the laminate is formed.
34. In one embodiment or the invention the first substrate is rigid
and the second substrate is rigid.
35. In one embodiment of the invention the first substrate is rigid
and the second substrate is flexible.
36. In another embodiment of the article of the invention the
bonding material is selected from the group consisting of viscous
liquids, viscoelastic solids, and mixtures thereof.
37. In another embodiment of the article of the invention the
bonding material is selected from the group consisting of
polyacrylics, silicones, polyolefins (polyoctenes, polyhexene),
rubber, polymers and mixtures thereof.
38. In a preferred embodiment of a method of the invention the
maximum haze value through the laminate is less than about 10
percent, more preferably less than about 5 percent, and most
preferably less than about 3 percent.
39. In one embodiment of a method of the invention step (c)
comprises the steps of (i) providing a layer of bonding material
over the abraded area of the first substrate wherein the bonding
material having a stress relaxation value of at least about 15% at
a temperature at which the laminate is formed; and (ii) placing the
second substrate over the coating in order to form a laminate.
40. In one embodiment of a method of the invention step (c)
comprises the steps of
41. (I) providing a construction comprising
42. (i) the second substrate;
43. (ii) the layer of bonding material having a stress relaxation
value of at least about 15% at a temperature at which the laminate
is formed coated on said second substrate;
44. (II) laminating together the construction and the first
substrate in a manner such that the bonding material layer having a
stress relaxation value of at least about 15% is in contact with at
least the abraded area of the first major surface of the first
substrate.
45. In another embodiment of a method of the invention step (c)
comprises the steps of
46. (I) providing a construction comprising
47. (i) the second substrate; and
48. (ii) the bonding material layer having a stress relaxation
value of less than about 15% at a temperature at which the laminate
is formed coated on at least a portion of the second major surface
of said second substrate;
49. (II) causing the bonding material layer of (I) (ii) to change
such that its stress relaxation value becomes at least about 15% at
a temperature at which the laminate is formed;
50. (III) laminating together the construction and the first
substrate in a manner such that the bonding material layer having a
stress relaxation value of at least about 15% is in contact with at
least the abraded area of the first surface of the first major
surface.
51. In one embodiment of a method of the invention the R.sub.max of
the first major surface of the first substrate in step (a) is at
least about 40 microns.
52. In one embodiment of a method of the invention the R.sub.max of
the first major surface of the first substrate in step (b) is about
25 microns or less.
53. In one embodiment of a method of the invention the R.sub.max of
the first major surface of the first substrate in step (a) is at
least about 40 microns to about 500 microns.
54. In one embodiment of a method of the invention the R.sub.max of
the first major surface of the first substrate in step (b) is about
15 microns or less.
55. In one embodiment of a method of the invention the R.sub.max of
the first major surface of the first substrate in step (a) is it
least about 40 microns to about 100 microns.
56. In one embodiment of a method of the invention the R.sub.max of
the first major surface of the first substrate in step (b) is about
8 microns or less.
57. In one embodiment of a method of the invention the maximum haze
value of the first major surface of the first substrate in step (b)
is at least about 30% and the maximum haze value through the
laminate in step (c) is less than about 20%.
58. In one embodiment of a method of the invention the first
substrate is a glass window.
59. In one embodiment of a method of the invention the first
substrate and the second substrate have the same shape, width and
length.
60. The present invention also provides a method comprising:
61. (a) providing a first substrate, the first substrate having a
first major surface and an opposite second major surface, wherein
the first substrate is selected from the group consisting of glass,
plastic and combinations thereof, wherein the first substrate has
at least one scratch on its first major surface and wherein the
first major surface of the first substrate has an R.sub.max greater
than about 1 micron;
62. (b) removing any visible contaminants on the first major
surface of the first substrate by cleaning;
63. (c) forming a laminate comprising (i) the first substrate, (ii)
a second substrate having a first major surface and an opposite
second major surface, wherein the second substrate comprises
immediately before, during and after formation of the laminate a
material selected from the group consisting of glass, amorphous
plastic in its glassy state, amorphous plastic in its rubbery
state, crystalline plastic in its glassy state, crystalline plastic
in its rubbery state and combinations thereof, and (iii) a bonding
material layer positioned between the first substrate layer and the
second substrate layer, wherein the bonding material layer is in
contact with at least the abraded area of the first major surface
of the first substrate and is in contact with at least a portion of
the second major surface of the second substrate layer;
64. wherein a maximum haze value through the laminate is less than
about 20 percent.
65. In a preferred embodiment of the article of the invention the
first substrate has a Scratch Visibility Test Rating of 1-2 and the
laminate has a Scratch Visibility Test Rating of 0-1.
66. In a preferred embodiment of the article of the invention the
first substrate has a maximum haze value of about 20 or greater and
the maximum haze value through the laminate article is less than
about 20 percent.
67. In a preferred embodiment of a method of the invention the
first substrate has after an abrading step a maximum haze value of
about 20 or greater and the maximum haze value through the laminate
article is less than about 20 percent.
68. The present invention also provides articles wherein the first
substrate is scratched and/or abraded on both sides and bonding
material and a second substrate are applied to both sides of the
scratched first substrate. The final article preferably has the
same haze value and scratch test values discussed elsewhere
herein.
69. The first substrate and second substrate are typically
permanently bonded to each other although the second substrate may
optionally be readily removable.
BRIEF DESCRIPTION OF THE DRAWINGS
70. FIG. 1 illustrates a plan view of a window 200.
71. FIG. 2 illustrates a plan view of the same window 200 as in
FIG. 1 except that it shows a vandal 207 scratching the window 200
with a rock 208.
72. FIG. 3 illustrates a plan view of the same window 200 as in
FIG. 2 except that the window 200 has been abraded with an abrasive
disk 212 over the scratches.
73. FIG. 4 illustrates a plan view of the same window of FIG. 3
wherein a coated substrate 214 is being moved into position for
placement onto the window 200.
74. FIG. 5 illustrates a plan view of the window of FIG. 4 wherein
the coated substrate 214 has been positioned into place thus
rendering the window 200 clear enough so that the tree 204 can be
viewed therethrough.
75. FIG. 6 is a perspective view of the coated film 214 which is
shown in FIGS. 4 and 5. The coated film comprises a plastic film
second substrate 216 and a bonding material layer 224.
76. FIG. 7 is a perspective view another embodiment of the coated
film of Example 6.
77. FIG. 8 is a cross-sectional view taken along line 8--8 on FIG.
1. FIG. 8 shows the window before it is scratched.
78. FIG. 9 is a cross-sectional view taken along line 9--9 on FIG.
2. FIG. 9 shows the window with scratches 206 therein.
79. FIG. 10 is a cross-sectional view taken along line 10--10 on
FIG. 3.
80. FIG. 11 is a cross-sectional view taken along line 11--11 on
FIG. 5.
81. FIG. 12 is a cross-sectional view of a coated film embodiment
230.
82. FIG. 13 is a cross-sectional view of a coated film embodiment
240.
DETAILED DESCRIPTION OF THE INVENTION
83. First Substrate
84. The first substrate should be relatively clean before
application of the bonding layer and the second substrate. If it is
not relatively clean, visible debris could become trapped in the
final article thus interfering with the haze or visibility of a
repaired scratch. The first substrate can be cleaned for example
with soap and water and a brush. This may be sufficient to remove
any debris, particularly debris which may be stripped in scratches.
However, since debris which may be trapped in the scratches can be
difficult to remove, abrasion may be necessary by itself or in
addition to cleaning.
85. The first substrate comprises glass, plastic or combination
thereof that has been damaged by scratching and/or abrading with,
for example, a rock or other abrasive articles such as sandpaper,
abrasive cloth, diamond earrings or tungsten-carbide tipped styli.
The first substrate, except for the damaged areas, is typically
transparent. The first substrate can optionally be tinted and/or
contain printed images. The first substrate could, for example, be
safety glass where two pieces of the glass are laminated to a
polyvinyl butyral film such that the film is between the two sheets
of glass. The first substrate could optionally be thermally
tempered glass where the glass has been heated and rapidly cooled.
The result is a stratified glass morphology where the outer
surfaces of the glass are hardened by the tempering process and the
center portion of the glass is under compression. Thermally
tempered glass, when cut or damaged through the outer tempered
layer will shatter into many pieces because the compressed inner
layer is no longer under compression in the damaged area. To
relieve the stress, the glass shatters. The first substrate could
optionally be chemically tempered glass where to 2-10 microns of
each side of the glass are hardened by a chemical process. In the
case of chemically tempered glass the center layer is not under
compression. If the hardened outer layer is damaged, chemically
tempered grass will not shatter like thermally tempered glass. The
first substrate can alternatively comprise plastics such as, for
example, polycarbonate or polymethylmethacrylate based
polymers.
86. Typically it is easier to scratch plastic than glass. Thus the
scratches in damaged glass are typically not as deep as those in
damaged plastic.
87. The scratched and/or abraded surface of the first substrate is
characterized by two measurements. The first measurement is
R.sub.max, where R.sub.max is the maximum peak to valley height of
the scratched and/or abraded surface of the first substrate. The
measurement describes the depth of the scratches and/or abrasions
on the surface
88. The second measurement used to characterize the surface is
R.sub.a. R.sub.a is an indication of the variability of the surface
roughness and is defined as the arithmetic mean of the departures
at the roughness profile from the mean line of the surface profile.
Both surface measurements are familiar to those skilled in the art
and are commonly used to characterize a surface. The units of
measure for R.sub.a and R.sub.max are typically in microns.
89. Mathematically the terms are described as follows.
R.sub.max=Y.sub.max-Y.sub.min wherein Y.sub.max=the highest
vertical point over the profilometer assessment length.
y.sub.min=the lowest vertical point over the profilometer
assessment length.
90. 1 R a = 1 L 0 L y ( x ) 2 x
91. where
92. L=The assessment length of the profilometer. During the test
the profilometer head moves over the sample and has a path of
typically 5 mm in the x direction. This can be adjusted on most
profilometers.
93. y=variation of the height and depth of the profile or the
vertical component of the data.
94. x=horizontal component of the profilometer motion as traverses
across the sample. L represents the maximum x value for the
measurement process.
95. Typically the R.sub.max value of a scratched glass substrate
such as a window pane ranges from about 1 to about 75 microns. For
plastic substrates, the damaged substrates typically have an
R.sub.max value ranging from about 1 to about 300 microns. The tool
used to measure R.sub.max of the damaged first substrate was a
profilometer manufactured by the Mahr Corporation of Cincinnati
Ohio (Model: Perthometer M4P).
96. The method of repair and surface preparation of the first
substrate required to provide a final laminate article having the
desired haze value depends on the composition of the first
substrate, the cleanliness of the first substrate including damaged
areas and the depth or severity of the damage. In a less complex
case where the damaged first substrate is clean and the severity of
the scratches is minimal (i.e. the R.sub.max is less than about 50
microns) then no additional surface preparation is typically
required. However, frequently the scratches contain debris and need
to be aggressively cleaned such as with a scrubbing pad and a soap.
However, debris in some cases is most effectively removed from the
damaged first substrate by an abrasion process. Several abrasive
methods can be used to abrade the damaged surface of the first
substrate including sand blasting, high pressure water with an
abrasive grit, grinding with a flexible diamond or aluminum oxide
abrasive material, etc. Care needs to taken when abrading the first
substrate especially thermally tempered glass. If the outer layer
is penetrated by the damage or by the abrasion process, the glass
may shatter. For thermally tempered glass the depth of each of the
outer tempered layers is typically 30% of the thickness of the
glass. The thickness of the compression layer is typically 40% of
the thickness of the glass.
97. The abrasion process also smoothes the topography of the
scratches. The depth of the scratches is reduced and preferably the
sharpness of the scratches is minimized. The preferred method for
cleaning and reducing the depth of scratches is a robotic abrasion
process that grinds the surface of the first substrate such as
glass with a 74 to 250 micron 3M.TM. Flexible Diamond abrasive
available from the 3M Company. With such a robotic system for
example, a damaged window 50 cm.times.125 cm in size and scratched
with scratches such that the R.sub.max of the window surface is 75
microns can be completely abraded in 8-15 minutes depending on the
type or glass being abraded. The cleaning and/or abrading process
of substrates comprising plastic arc similar to glass substrates.
In the simplest case where the scratch is clean and not severe
(where R.sub.max is less than about 50 microns) then no surface
preparation is required. The difference between surface preparation
between a glass substrate and plastic substrate is typically in the
type of abrasive used. Typically aluminum oxide abrasive materials
are used on plastic substrates and the time required to abrade the
substrate is typically less than for glass.
98. The damage of the first substrate in some situations may not be
restricted to one surface of the substrate. It is possible for the
first substrate to be damaged on both the front and back surface.
An example is a glass or plastic bus shelter where passengers wait
for the arrival of the bus. It is common to observe scratching on
both surfaces of the plastic or glass that comprise the bus
shelter. In such a circumstance to provide the desired maximum haze
or desired visibility of a repaired scratch to a final laminate
article one would need to optionally clean and optionally abrade
each first substrate surface, followed by applications of a bonding
material and second substrate. The desired haze or visibility of a
repaired scratch values, etc. of the repaired structure should be
the same if only one surface was repaired.
99. Second Substrate
100. The second substrate comprises glass; an amorphous and/or
crystalline plastic material in its rubbery and/or glassy state
immediately prior, during and after lamination to the first
substrate; or a combination thereof. Examples of useful second
substrates include, for example, glass panes, pre-made plastic
films and combinations thereof such as safety glass. The second
substrate useful herein typically has substantially the same
(preferably the same) breadth, length, and width immediately
before, during, and after it is applied to the first substrate. For
example, a gel or liquid would not be considered to have the same
breadth, length, and width immediately before and after application
to a substrate.
101. The purpose of the second substrate is to act as a support for
the bonding layer and to provide a new undamaged surface in place
of the damaged first substrate. The second substrate provides
protection in addition to enhancing the strength and shatter
resistance of the first substrate. The second substrate is
typically transparent which means that it does not typically
detract from the observer's ability to distinguish images
therethrough. The second substrate can optionally be tinted or
contain printed images in a manner in which does not impact the
observer's ability to distinguish or read images through at least a
portion, preferably a major portion, and most preferably all of the
second substrate. The second substrate is not applied as a gel or a
flowable liquid but as glass and/or as an amorphous and/or
crystalline plastic in its rubbery or glassy state (preferably
glassy) immediately prior, during, and after application. The
"solid" nature of the second substrate makes application of the
second substrate much easier to the first substrate than would be
the spraying or coating a liquid or a gel. The uniformity of the
second substrate used herein (which is typically a pre-made plastic
film or glass pane) is far superior to that which could be obtained
by application of a liquid or gel which must later cure or set in
place. Uniformity of the second substrate is helpful in providing a
final laminate article with the desired optical properties (such as
haze or visibility of a repaired scratch). Another advantage of
having a second substrate that is not a liquid or gel is that the
thickness of the second substrate can be accurately defined in
advance of the application. The thickness can be important where
the second substrate offers protection and enhances the safety of
the first substrate.
102. Typically a second substrate which comprises a polymeric
material has a tensile strength as measured according to ASTM D882
of about 20 to about 2000 kPa, preferably about 70 to about 1400
kPa, and most preferably about 350 to about 100 kPa.
103. Typically a second substrate which comprises a polymeric
material has an elongation as measured according to ASTM D882 of
about 5 to about 1000 percent, preferably about 5 to about 500
percent, and most preferably about 350 to about 1000 percent.
104. Typically a second substrate which comprises a polymeric
material has a tear strength as measured according to ASTM D1004 of
about 0.4 to about 40 N, preferably about 4 to about 20 N, and most
preferably about 12 to about 20 N.
105. Typically a second substrate which comprises a polymeric
material has a thickness of about 25 to about 4000 microns,
preferably about 50 to about 1000 microns, and most preferably
about 50 to about 250 microns.
106. For a non-polymeric second substrate such as glass, for
example, the thickness typically ranges from about 1 mm to about 10
mm, preferably about 2 mm to about 7 mm.
107. Depending on the application, the second substrate may need to
resist a wide variety of environmental conditions including
prolonged exposure to high temperatures, high humidity or
ultraviolet light. The second substrate may, for example, comprise
a polymer including but not limited to those selected from the
following broad classifications of materials: polyesters,
polycarbonates, acrylics, polymethacrylates, polyurethanes,
urethane acrylate polymers, epoxy acrylate polymers, polyacetals,
polystyrene, polyvinyl chloride, and polyolefins such as ethylene
vinyl acetate copolymers, polyethylene, polypropylene, ionomers of
ethylene, and mixtures thereof. The second substrate may comprise,
for example, a blend of the materials listed above or multilayer
structures of the materials listed.
108. The second substrate may optionally further comprise additives
such as, for example, flame retardants, ultraviolet light
absorbers, antioxidants, and hindered amine stabilizers, and
combinations thereof. The second substrate may optionally further
comprise an abrasion resistant coating on the surface that is not
in contact With the bonding layer. Multifunctional acrylate or
methacrylate abrasion resistant coatings are described in U.S. Pat.
No. 5,633,049, issued on May 27, 1997.
109. The second substrate may optionally be primed to enhance the
adhesion of the bonding layer thereto. The primes may include, for
example, surface treatments such as corona treatments or flame
treatments or may include, for example, coatings such as acrylics,
polyvinyl chloride, polyvinyl chloride/polyvinyl acetate
copolymers, polyesters, urethanes, polyamides, and chlorinated
olefins or maleic anhydride modified olefins.
110. Bonding Material
111. The bonding material is preferably transparent and preferably
flows into the scratches and/or abraded areas of the damaged first
substrate which aids in preparation of the final article with the
desired maximum haze value or visibility of repaired scratch value.
As the haze is improved, the transparency of the article is
improved. The bonding material may, for example, be a solid,
semi-solid or liquid. The bonding material is preferably a
poly(acrylate) or (methacrylate), polyolefin or rubber based
pressure sensitive adhesive that has a stress relaxation value of
about 15 percent or greater. Stress relaxation is a property that
is indicative of the viscoclastic flow of the material. Stress
relaxation is measured as described in the Test Methods. Bonding
materials with little or no flow properties relax only 0 to less
than about 15% of the applied stress. Bonding materials which are
useful in this invention preferably have the viscoelastic flow
properties needed for flowing into the abraded and/or scratched
surface of the first substrate. They preferably stress relax from
greater than about 15 to 100% of the applied stress. Stress
relaxation values are temperature sensitive. The value for stress
relaxation are values obtained when stress relaxation is measured
at about 23.degree. and about 50% relative humidity.
112. The thickness of the bonding material is very important, as
the R.sub.max of the scratches increases, the bonding layer
thickness preferably increases so enough mass of the bonding layer
is available to flow into the damaged areas of the first substrate.
The thickness of the coated bonding layer also depends on the
amount of flow exhibited by the bonding layer. A bonding layer made
of a flowable viscous liquid preferably should be coated at a
thickness less than the deepest scratch while bonding layers made
of polymers that have less viscoelastic flow preferably should be
coated at a thickness greater than the scratch requiring
repair.
113. The refractive index of the bonding layer may be important
when repairing deep scratches. To minimize the visibility of a
repaired scratch, matching the index of refraction (i.e. typically
within about 0.05 more preferably exactly the same) of the bonding
layer to the index of refraction on the first substrate is
preferred especially if the R.sub.max of the first substrate is
greater than 50 microns. The closer the match in refractive index,
the typically less visible the repaired scratch. On first
substrates where the R.sub.max is less than 25 microns the matching
the refractive index of the first substrate with the bonding layer
is less important.
114. The bonding material can optionally further comprise one or
more additives including but not limited to those selected from the
group consisting of flame retardants, ultraviolet light absorbers,
antioxidants, and hindered amine stabilizers. The bonding layer is
preferably laminated to a release liner to protect the bonding
layer surface from handling damage or dirt pick up.
115. To facilitate application of a bonding material coated second
substrate to the abraded and/or scratched first substrate a
water/alcohol or water/detergent mixture may be used, for example.
An example thereof is a 25 percent by weight isopropanol water
solution. Such a mixture is typically applied with a spray bottle
to the scratched and/or abraded substrate. The release liner
protecting the bonding layer of the bonding material coated
substrate is removed and the bonding material is also sprayed with
such a mixture. The wet bonding material layer surface and the wet
first substrate surface are brought into contact. The excess
solution is removed from the interface with a squeegee or a roller
such that no trapped air or excess solution is left at the
interface of the first substrate and the bonding material. A
solution of 0.1% to 1% by weight liquid detergent in water based on
the total weight of the detergent/water solution is also useful as
an aid for application.
116. The bonding layer can alternatively be applied by first
forming a laminate comprising the second substrate, the bonding
layer coated on one surface thereof, and a non-tacky coating coated
over the bonding layer. The bonding layer may, for example,
comprise a pressure-sensitive adhesive. For example, a pressure
sensitive adhesive may be applied to one side of the second
substrate, coated with a thin non-tacky coating and dried. This
non-tacky surface prevents the bonding layer inadvertently adhering
to a surface prior to use. This non-tacky surface upon subsequent
conversion to a tacky surface would later be positioned against the
first substrate.
117. The non-tacky coating allows large sections of the second
substrate to be more easily applied to a first substrate in
environments (such as a bus, for example) where there is an
abundance of debris such as dust and dirt, without as much concern
for the debris collecting on the tacky bonding material.
118. An example of a useful non-tacky material for this purpose is
a water-soluble cellulose based non-tacky material such as
Methocel.TM. A15-LV methocellulose from Dow Chemical of Midland,
Mich. Such a material is typically coated such that the dry
thickness is about 1 to about 5 microns. Water is typically used to
convert the non-tacky coating to a tacky coating although a
water/detergent and/or a water/alcohol solution may also be used.
Such a spray is typically also used on the first substrate to
facilitate application of the second substrate and bonding layer.
For example, water may be sprayed on the cellulose based surface
coating and on the first substrate prior to lamination of the
cellulosic surface to the first substrate surface. The trapped
water is removed from the first substrate/water soluble coating
interface using a squeegee or roller. The thin soluble coating is
dissolved during the process exposing the pressure sensitive
adhesive to the first substrate. In this case the pressure
sensitive adhesive layer has a high degree of viscoelastic flow and
the cellulose based coating in the water saturated state has a high
degree of viscoelastic flow. When the water evaporates the
cellulose based coating and the pressure sensitive adhesive
typically have filled the voids in the scratched and/or abraded
first substrate and the remaining cellulose based layer becomes
rigid. The pressure sensitive adhesive bonds to the first substrate
in regions where the cellulose based coating has been completely
dissolved.
119. The bonding material may optionally be in the state of a
viscous liquid. The viscous liquid is preferably 100% solids so no
solvent evaporation is required. The viscous liquid is preferably
transparent. The viscous liquid typically comprises acrylate
monomers such as those selected from the group consisting of
acrylates, methacrylates, urethane acrylates or epoxy acrylates,
and a photoinitiator(s) required to activate polymerization by
radiation such as UV or visible light. The viscous liquid can be
coated onto the second substrate and laminated to the first
substrate using a squeegee and roller to eliminate any trapped air
at the interface. The viscous liquid could also be applied directly
to the damaged first substrate. The second substrate is applied to
the first substrate coated with the viscous liquid. Any trapped air
is removed with a squeegee or a roller. The viscous solution is
subsequently cured. This embodiment is very useful at repairing
severely damaged first substrates with deep scratches and where
repair time is a critical factor.
120. Release Liner
121. Preferably a release liner protects the surface of the bonding
layer not in contact with the second substrate. Preferably the
release liner imparts no texture to the bonding layer, shields the
bonding layer from contamination from debris, and is easily
released from the bonding layer prior to application. Useful
release liners include, for example, polyester or polyolefin films.
These films may be coated with silicone or fluorinated release
surfaces to facilitate release from the bonding layer. For added
dimensional stability, the release liner may comprise a film and
paper laminate provided the paper imparts no texture or a texture
that does not detract from the transparency of the bonding
layer.
122. The invention will be better understood by referring to the
following figures.
123. FIG. 1 illustrates a plan view of a window 200. A rim 202
extends around the window 200. An observer 205 views a tree 204
through the window 200.
124. FIG. 2 illustrates a plan view of the same window 200 as in
FIG. 1 except that it shows a vandal 207 scratching the window 200
with a rock 208. The tree 204 can no longer be clearly viewed
through the window 200.
125. FIG. 3 illustrates a plan view of the same window 200 as in
FIG. 2 except that the window 200 has been abraded with an abrasive
disk 212 over the scratches. Typically the abrasive disk 212 would
be a part of a grinder held by an operator. Neither the grinder nor
operator are shown, however.
126. FIG. 4 illustrates a plan view of the same window of FIG. 3
wherein a coated substrate 214 is being moved into position for
placement onto the window 200.
127. FIG. 5 illustrates a plan view of the window of FIG. 4 wherein
the coated substrate 214 has been positioned into place thus
rendering the window 200 clear enough so that the tree 204 can be
viewed therethrough.
128. FIG. 6 is a perspective view of the coated film 214 which is
shown in FIGS. 4 and 5. The coated film comprises a plastic film
second substrate 216 and a bonding material layer 224.
129. FIG. 7 is a perspective view another embodiment of the coated
film of Example 6. The coated substrate comprises a glass sheet
second substrate 222 and bonding material layer 224.
130. FIG. 8 is a cross-sectional view taken along line 8--8 on FIG.
1. FIG. 8 shows the window before it is scratched.
131. FIG. 9 is a cross-sectional view taken along line 9--9 on FIG.
2. FIG. 9 shows the window with scratches 206 therein.
132. FIG. 10 is a cross-sectional view taken along line 10--10 on
FIG. 3. FIG. 10 shows the window after grinding in which the
scratches 206 are now of lesser depth due to the grinding
operation.
133. FIG. 11 is a cross-sectional view taken along line 11--11 on
FIG. 5. The bonding layer 218 and second substrate 216 are bonded
to the glass. The bonding layer 218 has flown into the scratches
206.
134. FIG. 12 is a cross-sectional view of the coated film 230. The
coated film comprises a hard coat (release layer) 232, a plastic
film second substrate, a bonding layer 236 and a plastic release
liner 238.
135. FIG. 13 is a cross-sectional view of the coated film 240. The
coated film comprises a hard coat (release layer) 262, a plastic
film second substrate 244, a bonding layer 246, and a water soluble
detackification layer 246.
Test Methods
Effect of Sample on Visual Acuity of Observer
136. An observer with 6 meter/6 meter vision is positioned 3 meters
from a 3 Meter Snellen eye chart, covers one eye and reads with the
uncovered eye the line which corresponds to 6 meter/6 meter vision.
(An observer with vision corrected to 6 meter/6 meter vision is
considered to have 6 meter/6 meter vision as long as the corrective
lenses are worn during the test.) A sample of the article or
material to be evaluated is then placed 3 centimeters in front of
the observer's uncovered eye while the other eye remains covered to
determine if the sample causes a loss of visual acuity. If the
viewer can still read the line of letters indicative of 6 meter/6
meter vision it is considered that there is no interference with
visual acuity caused by the sample. If the line indicative of 6
meter/6 meter vision cannot still be read the smallest line which
can still be read is recorded. (For example 6 meter/9 meter, 6
meter/12 meter, 6 meter/15 meter, 6 meter/18 meter, etc.)
137. Preferably with respect to an article of the invention the
answer can read a line indictive of 6 meter/18 meter vision or
better, preferably 6 meter/15 meter vision or better, more
preferably 6 meter/12 meter vision or better, even more preferably
6 meter/6 meter or better, and most preferably 6 meter/6 meter or
better.
138. Stress Relaxation of the Bonding Layer
139. The sample preparation techniques for measuring stress
relaxation is slightly different depending on the embodiment of the
invention being evaluated. The specific procedures and test methods
are outlined below for each embodiment. The percent stress
relaxation in each case is calculated as follows (wherein the loads
are in the same units). Typically the bonding layer useful
according to the present invention, regardless of the embodiment,
exhibits a stress relaxation of greater than about 15 percent
preferably greater than about 20 percent, and most preferably
greater than about 25 percent.
Percent Stress Relaxation=(initial load-load after 120
sec).times.100/initial load
140. Stress Relaxation Test Procedure Used When the Bonding Layer
is Inherently Tacky
141. The bonding material to be evaluated is coated on a
non-extensible backing film (such as a polyester film with a
minimum thickness of 100 microns, for example) to a dried thickness
of at least 25.4 microns. A variety of coating methods may be used.
The coating needs to be applied such that the surface of the
coating is free from dirt and smooth. The coated film is cut into a
25 mm.times.150 mm strip.
142. A 50 mm.times.150 mm #6 stainless steel test panel is cleaned
with toluene and dried. The coated film is applied via its coating
side to the steel panel such that a 25 mm.times.25 mm area of the
coated film is in contact with the panel and the remaining portion
of the coated film hangs over the edge of the panel. Thumb pressure
is used to apply the coated film to the panel. The interface
between the coated film and the panel is free of trapped air
bubbles and the coated film and the panel are in intimate contact.
The panel with the coated film applied thereto is mounted in a
tensile testing device (such as an Instron Model # 5565 from the
Instron Corporation of Houston Tex.) in its bottom jaw while the
overhang portion of the coated film is held in its upper jaw. A
shear load of 4.5 kg (i.e. the initial load) is applied to the
panel with the coated film applied thereto with a jaw speed of 2.54
cm/sec. The fraction of the remaining load on the sample after a
120-second time interval is recorded. The test is conducted at
about 23.degree. C. and about 50% Relative Humidity (R.H.), but
could be conducted at other temperatures such as the use
temperature or at a temperature range of 0-25.degree. C., if
desired.
143. Stress Relaxation Procedure Used When the Bonding Layer is
Coated with a Water Soluble Detackifying Layer
144. The test panel procedure begins by cleaning the 50
mm.times.150 mm #6 stainless steel panel with toluene and allowing
the panel to dry. Apply approximately 5 g of water on the panel
directly in the 25 mm.times.25 mm location of the coated film to be
tested. Apply the coated film onto the wet test panel such that a
25 mm.times.25 mm area of the coated film is in contact with the
test panel and the remaining portion of the coated film hangs over
the edge of the panel. With a roller, squeegee or thumb pressure,
remove the excess water from the interface. After 72 hours at about
23.degree. C. and about 50% R.H., conduct the stress relaxation
test. The panel with the coated film applied thereto is mounted in
a tensile testing device (such as an Instron Model # 5565 from the
Instron Corporation of Houston Tex.) in its bottom jaw while the
overhang portion of the coated film is held in its upper jaw. A
shear load of 4.5 kg (i.e. the initial load) is applied to the
panel with the coated film applied thereto with a jaw speed of 2.54
cm/sec. The fraction of the remaining load on the sample after a
120-second time interval is recorded. The test was conducted at
about 23.degree. C. and about 50% R.H., but could be conducted at
other temperatures such as the use temperature or at a temperature
range of 0-25.degree. C., if desired.
145. Stress Relaxation Procedure Used When Bonding Layer is
Comprised of a Reactive Liquid
146. The 50 mm.times.150 mm #6 stainless steel panel is cleaned
with toluene and allowed to dry. The unreacted bonding material is
coated on a non-extensible backing preferably a transparent corona
treated polyester film greater than 50 micron in thickness. The
size of the coated sheet is 25 mm.times.150 mm. The coated film is
applied to the panel with the coating of liquid bonding layer in
contact with the panel such that a 25 mm.times.25 mm area of coated
film is in contact with the panel. The remaining portion of the
strip hangs over the edge of the panel. The coating is cured.
Curing may be accomplished with UV light or by a thermal process
depending on the chemistry of the coating. The stress relaxation is
measured when the coating is cured. The panel with the coated film
applied thereto is mounted in a tensile testing device (such as an
Instron Model #5565 from the Instron Corporation of Houston Tex.)
in its bottom jaw while the overhang portion of the coated film is
held in its upper jaw. A shear load of 4.5 kg (i.e. the initial
load) is applied to the panel with the coated film applied thereto
with a jaw speed of 2.54 cm/sec. The fraction of the remaining load
on the sample after a 120-second time interval is recorded. The
test was conducted as about 23.degree. C. and about 50% R.H., but
could be conducted at other temperatures such as the use
temperature or at a temperature range of 0-25.degree. C., if
desired.
147. Haze Test
148. The haze of a sample is measured by using a Gardner XL211
Hazeguard device. The procedure used is in accordance to ASTM
D1003-95 with the following exceptions
149. 1. The sample size is rectangular with a minimum size of 40
mm.times.40 mm.
150. 2. The sample is scanned for areas of the maximum haze. These
selected areas are measured and the maximum haze value is
reported.
151. 3. The sample is allowed to equilibrate at about 23.degree. C.
and about 50% R.H. for 72 hours prior to testing.
152. 180 Degree Peel Adhesion to Glass-Procedure Used When the
Bonding Layer is Inherently Tacky
153. A 100 mm.times.200 mm flat glass plate is cleaned with toluene
and allowed to air dry prior to application of the material (a
second substrate with a bonding layer) to be tested. The adhesion
to glass is measured by bonding a 25 mm.times.150 mm of the
material to be tested using a rubber roller such that no trapped
air exists at the glass bonding layer interface and a 25
mm.times.50 mm of the material being tested is hanging over the
edge of the glass plate. The material being tested is allowed to
dwell on the glass at least 10 minutes. The glass plate is clamped
onto the carriage of a Slip-Peel Tester Model SP102C-3090 adhesion
tester (IMASS Inc., Accord Mass.). The overhang of the sheet is
clamped to a sensor of the tester. As the carriage moves, the force
to peel the sheet is measured at 228.6 cm/min at an angle of 180
degrees. The average force over a 2 second period is recorded. The
test is conducted at about 23.degree. C. and about 50% R.H.
154. The glass panel is inspected for residue (such as adhesive
residue) left after peel. Preferably substantially no residue
remains on the glass. Most preferably no residue remains on the
glass.
155. 180 Degree Peel Adhesion to Glass-Procedure Used When the
Bonding Layer is Coated With a Water-Soluble Detackifying Layer
156. A 100 mm.times.200 mm flat glass plate is cleaned with toluene
and allowed to air dry prior to application of the material (a
second substrate/bonding layer/water soluble detackifying layer
laminate) to be tested. A 0.5% Joy.TM. dishwashing detergent 99.5%
water solution is applied over the glass surface. The adhesion to
glass is measured by bonding a 25 mm.times.150 mm of the material
to be tested to the glass such that the detackifying layer is in
contact with the detergent and water coated glass. A rubber roller
is used such that no large bubbles of water are present under the
material. A 25 mm.times.50 mm section of the material being tested
hangs over the edge of the glass plate. The material being tested
is allowed to dwell on the glass for 72 hours at about 23 degree C.
and 50% R.H. The glass plate is clamped onto the carriage of a
Slip-Peel Tester Model SP-102C-3090 adhesion tester (IMASS Inc.,
Accord Mass.). The overhang of the sheet is clamped to a sensor of
the tester. As the carriage moves, the force to peel the select is
measured at 228.6 cm/min at an angle of 180 degrees. The average
force over a 2 second period is recorded. The test is conducted at
about 23.degree. C. and about 50% R.H.
157. The glass panel is inspected for residue (such as adhesive
residue) left after peel. Preferably substantially no residue
remains on the glass. Most preferably no residue remains on the
glass.
158. 180 Degree Peel Adhesion to Glass-Procedure Used When the
Bonding Layer is a Reactive Liquid
159. A 100 mm.times.200 mm flat glass plate is cleaned with toluene
and allowed to air dry prior to application of the material (a
second substrate with a reactive liquid bonding layer) to be
tested. The adhesion to glass is measured by bonding a 25
mm.times.150 mm of the material to be tested such that the bonding
material is in contact with the glass using a rubber roller such
that no air bubbles are present under the material and a 25
mm.times.50 mm section of the material being tested is hanging over
the edge of the glass plate. The bonding material is cured. The
bonding material can be accomplished with UV light or by a thermal
process depending on the chemistry of the coating. The glass plate
is clamped onto the carriage of a Slip-Peel Tester Model SP-
102C-3090 adhesion tester (IMASS Inc., Accord Mass.). The overhang
of the sheet is clamped to a sensor of the tester. As the carriage
moves, the force to peel the sheet is measured at 228.6 cm/min at
an angle of 180 degrees. The average force over a 2 second period
is recorded. The test is conducted at about 23.degree. C. and about
50% R.H.
160. The glass panel is inspected for residue (such as adhesive
residue) left after peel. Preferably substantially no adhesive
residue remains on the glass. Most preferably no adhesive residue
remains on the glass.
161. Scratch Visibility Test
162. The sample to be evaluated is placed at a 45.degree. angle
over a black substrate in a McBeth light booth (Model No. STLA
available from the McBeth Corporation, Newborough, N.Y.) and viewed
at a distance of 3 meters under daylight lamp settings by an
observer with vision of 6 meter/6 meter or vision corrected to 6
meter/6 meter. The sample is rated for the visibility of
scratch(es). The most visible scratch in sample is examined and
used to rate the sample. A rating of 0 indicates that no
scratch(es) are visible in the sample. A rating of 1 indicates the
scratch(es) be seen with great difficulty. A rating of 2 indicates
the scratch(es) in the sample can be seen without difficulty. This
test can be performed for example on a singe scratched substrate or
a laminate article such as the article of the invention. When one
compares the article of the invention itself to the first scratched
substrate one should preferably see a reduction in the test value
of at least 1. A scratched first substrate typically has a rating
of 1-2. An article of the invention preferably has a test value of
0-1 more preferably 0. To test a single layer of a preformed
laminate such as the first substrate for scratches, one could take
apart the laminate and clean the bonding material from the
substrate to test the single scratched first substrate.
EXAMPLES
163. All the test methods referred to in the Examples were carried
out as described in the "Test Methods" section above. All parts,
percentages, ratios etc in the example are by weight unless
indicated otherwise.
Example 1
164. A 30 cm.times.30 cm piece of laminated safety glass from
Hillcrest Glass in Minneapolis, Minn. was scratched with a carbide
tipped scribe from General Tools Manufacturing Company Inc. New
York, N.Y. Four scratches were made in the safety glass on one side
thereof. The scratches, which were each approximately straight and
each approximately 25 cm long were positioned approximately
parallel to each other at spacing of approximately 1.25 cm. The
R.sub.max of the scratched surface ranged from 16-49 microns. A
rotary grinder with a water center feed using a 125-micron flexible
diamond abrasive disk under the tradename 3M.TM. Flexible Diamond
Products from 3M Company in St. Paul, Minn. was used to grind down
the area over and surrounding the scratches. The speed of the
rotary grinder was 2400 rpm. The abrasive disk was 12.7 cm in
diameter. The pressure applied to the abrasive disk was 160 Newtons
and the abrasive disk was held at a 4 degree angle to the
horizontal. The abraded surface of the glass was characterized
using a profilometer manufactured by the Mahr Corporation of
Cincinnati, Ohio (Model: Perthometer M4P). The R.sub.max and
R.sub.a of the abraded surface were measured. The R.sub.max or the
maximum peak to valley height in the abraded region was measured in
the range of 6- 13 microns. The R.sub.a of the abraded area or the
arithmetic mean of the departures of the roughness profile from the
mean line was measured to be 0.60-0.71 microns using the
profilometer.
165. A bonding material solution comprising 96 parts by weight of
isooctyl acrylate and 4 parts by weight of acrylamide was prepared
in a 50% heptane/50% ethyl acetate solution using
2,2'-azobis(isobutyronitrile) free radical initiator available
under the trademark designation "VAZO.TM. 64" from the E. I. DuPont
Company.
166. The following components were added to a reaction vessel: 19.2
kg of isooctyl acrylate, 0.8 kg of acrylamide, 40 kg of heptane and
40 kg of ethyl acetate. While constantly stirring under a nitrogen
atmosphere and controlling the temperature between
70-.degree.100.degree. C., 270 grams of VAZO.TM. 64 was added to
the vessel in three 90-gram increments. The resulting polymer had a
conversion of 98%. The Brookfield viscosity was measured (#3
spindle at 12 rpm) at 2000-2800 cps at a solids level of 19-23%.
The inherent viscosity of the polymer was 1.25-1.40 dl/gram.
167. A second substrate with a bonding layer coated on one side
thereof was prepared by coating the bonding material solution
described above on a 15 cm.times.100 cm.times.125 micron thick
optically clear biaxially oriented corona treated polyester film
using a knife coater at a wet thickness of 175 microns. The sample
was dried in an air convection oven for 10 minutes at 82.degree. C.
The dry thickness of the coating on the coated substrate was 20- 25
microns. The tacky bonding layer of this coated substrate was
protected by laminating an optically clear silicone coated
polyester film to the tacky bonding layer. The linear used was 1-2
PESTRD (PI)-7200 from DCP Lohja Inc. of Lohja Calif.
168. An appropriate size piece of the second substrate coated with
bonding layer and protective silicone coated polyester film was cut
out in order to test the stress relaxation of the bonding material.
The silicone coated protective film was removed. The stress
relaxation of the bonding layer was measured to be 65% using the
"Stress Relaxation Test Procedure for Inherently Tacky Bonding
Layers".
169. The haze of the abraded glass through the abraded region was
measured. The haze of the abraded glass ranged from 60-65%. A 50
mm.times.50 mm sample of the bonding material coated on the
polyester film was applied onto the abraded glass surface, after
removing the protective silicone coated protective film, using a
0.5% Joy.TM. dishwashing detergent available from Procter and
Gamble, Cincinnati, Ohio/99.5% water solution at the interface
between the polyester second substrate coated with the bonding
layer and the glass. The polyester second substrate coated with the
bonding layer was placed coated side down on the glass. The extra
solution was pressed out of the interface between the coated film
and the glass with a squeegee. The second substrate and the bonding
layer were allowed to dwell for 72 hours and the haze through the
polyester/bonding layer/glass laminate assembly was measured to be
4.8%.
170. An appropriate size piece of the second substrate coated with
bonding layer and protective silicone coated polyester film was cut
in order to test the 180.degree. peel adhesion to glass using the
"180.degree. Peel Adhesion to Glass-Procedure for Inherently Tacky
Binding Layers." The silicone coated protective film was removed.
The 180 Degree Peel Adhesion to glass of the coated polyester was
950 g /2.54 cm wide sample and no residue was observed upon
removal. Visual acuity was measured through the polyester/bonding
material/glass laminate assembly at 6 meter/6 meter.
171. This "Scratch Visibility" was measured at 2.
Example 2
172. Example 1 was replicated except that the second
substrate/bonding material combination was applied to the abraded
glass panel without using the dishwashing detergent and water
interface. The second substrate bonding layer combination was
applied to the abraded area of the same abraded piece of safety
glass as in Example 1 but not on top of the second
substrate/bonding layer combination of Example 1. This was possible
due to the fact that the abraded area of the piece of glass was
much larger than the substrate/bonding layer combination for both
Examples 1 and 2. The second substrate and bonding layer
combination was allowed to dwell on the glass for 72 hours and the
resulting haze was measured to be 4.4%. The Visual Acuity was
measured at 6 meter/6 meter. The 180.degree. peel adhesion to glass
using "180.degree. Peel Adhesion to Glass-Procedure used when
Bonding Layer is Inherently Tacky" was 950 g 12.54 cm and no
residue was observed on the panel. The stress relaxation of the
bonding material was evaluated by providing an appropriate sized
piece of bonding material/second substrate combination. The stress
relaxation was measured at 65% using the test "Stress Relaxation
Test Procedure Used When Bonding Layer is Inherently Tacky".
Example 3
173. A scratched polycarbonate sheet approximately 300 mm.times.600
mm.times.13 mm with scratch depths up to 250 microns was provided.
The numerous scratches which were random in direction and length
covered most of one side of the window. The scratched polycarbonate
sheet was abraded to a unifornm textured surface. The grinder used
was a Flex.TM. LW 603VR with a center water feed distributed by
Braxton-Bragg Corp. Knoxville Tenn. The backup pad was a 3MTM
Stick-It.TM. Disc Pad CWF (approximately 12.7 mm in diameter). The
surface was prepared by a three step abrasion process. The deep
scratches were removed by using a 3M.TM. Imperial.TM. Microinishing
Film--100 micron grade. The grinder speed was approximately 2200
revolutions per minute. The pressure of the grinder was manual
pressure ranging from 1-40 Newtons. The angle of the grinder pad to
the polycarbonate substrate varied from parallel to 10 degrees off
the parallel. The surface of the polycarbonate sheet was kept
saturated with water to reduce friction and to minimize dust. The
second step was conducted dry using a 60 micron grade of 3M.TM.
Imperial.TM. Microfinishing film using the speed, pressure and
angle in the first step. The third step was conducted dry using a
40 micron grade of 3M.TM. Imperial.TM. Microfinishing film using
the speed, pressure and angle in the first step. The surface
roughness of the abraded polycarbonate was characterized by an
R.sub.max of 1.4-7.5 microns and an R.sub.a of 0.16-1.1 microns.
The haze of the abraded polycarbonate was 65-82%. A second
substrate with a bonding layer coated thereon as described in
Example 1 was applied to the abraded polycarbonate using the
procedure outlined in Example 1. The second substrate/bonding layer
sample was allowed to dwell on the polycarbonate for 72 hours and
the haze measured through the second substrate/bonding
layer/polycarbonate laminate was measured to be 8.5%.
Example 4
174. A second substrate coated with bonding material which was
covered with a protective silicone coated polyester film as
described in Example 1 was prepared. The protective release liner
was removed and the bonding surface was coated with a water-soluble
cellulosic coating using a knife coater. The formulation of the
cellulosic coating was 1.6 parts by weight Methocel.TM. (A 15 LV)
methocellutlose from the Dow Chemical Co. of Midland, Mich. and
98.4 parts by weight of distilled water. The methocellulose was
dissolved in the water such that the viscosity of the solution was
15 centipoise using a Brookfield viscometer with a #1 spindle at a
rotation rate of 60 rpm. The wet thickness of the coating was 25
microns and the dry thickness of the coating was 5 microns. The
film with the cellulosic treated bonding layer was applied to the
same abraded safety glass from Example 1 (in an area where no other
second substrate/bonding material combinations had been bonded)
with the dishwashing detergent and water technique described in
Example 1. After a 72 hour dwell on the abraded glass panel, the
haze was measured to be 4.4%. The stress relaxation of the bonding
material was measured at 65% following the test "Stress Relaxation
Procedure Used When the Bonding Layer is Coated with a Water
Soluable Detackifying Layer". The Visual Acuity through the second
substrate/bonding layer/glass laminate was measured at 6 meter/6
meter.
175. The 180.degree. peel adhesion to glass of the second
substrate/bonding layer combination was determined following be
procedure given in the Test Methods except that the sample was
allowed to dwell at room temperature for 72 hours prior to testing.
The 180.degree. peel adhesion to glass was measured using the "180
Degree Peel Adhesion to Glass-Procedure Used When the Bonding Layer
is Coated with a Water-Soluable Detackifying Layer." The values
ranged from 580-1650g /2.54 cm wide sample (areas that were moist
had lower adhesion). No residue was observed on the glass after
removal.
Example 5
176. A polymer solution to be used in making a bonding material
comprising isooctyl acrylate and acrylic acid in a 90/10 ratio by
weight was prepared in ethyl acetate using benzoyl peroxide as a
thermal initiator. The following components were added to a
reaction vessel: 18.0 kg of isooctyl acrylate, 2.0 kg of
acrylamide, and 80 kg of ethyl acetate. While constantly stirring
under a nitrogen atmosphere and controlling the temperature between
70-100.degree. C., 45 grams of benzoyl peroxide was added to vessel
in three 15 gram increments every 2 hours. The resulting polymer
had a conversion of 95%. The Brookfield viscosity was measured (#3
spindle at 12 rpm) at 6000 cps at a solids level of 20%. The
inherent viscosity of the polymer was 1.80 dl/gram. The resulting
polymer had a conversion of more than 95%.
177. The bonding material solution was coated on a corona treated
side of a 15 cm.times.50 cm.times.125 micron optically clear
biaxially oriented polyester film using a knife coater at a wet
thickness of 225 microns. The coating was dried in an air
convection oven for 10 minutes at 82.degree. C. The dry thickness
of the coating layer was 25-35 microns. The tacky bonding layer
coating was protected by laminating an optically clear silicone
coated polyester film to the bonding layer. The stress relaxation
of the bonding material layer was measured to be 45% using the
"Stress Relaxation Test Procedure Used When the Bonding Layer is
Inherently Tacky". The initial haze of the abraded glass ranged
from 60-65%. A 50 mm.times.50 mm sample of the bonding layer coated
on the polyester film was cut and the protective liner was removed.
The coated polyester was applied onto the same glass surface which
had been abraded with a 125 micron diamond abrasive described in
Example 1 using a 0.5% Joy.TM. detergent and water solution at the
interface between the coated polyester and the glass in an area
where no other second substrate/bonding material combinations had
been bonded. The excess solution was forced out of the interface
using a squeegee. After a 72-hour dwell on the glass surface the
haze through the second substrate/bonding layer/glass laminate was
measured to be 8.8%. The 180.degree. peel adhesion to glass was
measured using the " 180 Degree Peel Adhesion to Glass-Procedure
Used When Bonding Layer is Inherently Tacky." The 180.degree. peel
adhesion was 1850 g/2.54 cm wide sample and only a slight adhesive
residue (less than 5%) was observed on the glass upon removal of
the coated polyester. The Visual Acuity was measured at 6 meter/6
meter.
Comparative Example 1
178. Comparative Example 1 demonstrates the importance of bonding
material in obtaining a final article with the desired haze
value.
179. This Comparative Example 1 compares a bonding layer that had
low viscoelastic flow properties and thus lower stress relaxation
due to crosslinking compared to the bonding material of Example 5
which had a higher stress relaxation value.
180. Example 5 was repeated with the following exceptions: The
bonding material solution was crosslinked with a bis-amide
crosslinker. To the bonding material solution, 3.0 percent of 5%
bis-amide crosslinker solution in toluene was added and stirred
with a propeller mixing blade for 5 minutes. The wet coating
thickness of the bonding material was 225 microns. The coating was
baked for 10 minutes at 75.degree. C. to evaporate the majority of
the solvent and baked 2 minutes at 100.degree. C. to accelerate the
crosslinking of the coating. The dried coating thickness was 25-35
microns. The stress relaxation of the bonding layer was measured at
15% when conducted using the "Stress Relaxation Test Procedure Used
When the Bonding Layer is Inherently Tacky". The haze through the
second substrate/bonding material layer/glass laminate after a 72
hour dwell using the procedure described in Example 1 was 27%. The
Visual Acuity was measured at 6 meter/15 meter. The 180.degree.
peel adhesion to glass was measured using the "180 Degree Peel
Adhesion to Glass-Procedure Used When Bonding Layer is Inherently
Tacky." The 180.degree. peel adhesion was 125 g/2.54 cm wide sample
and no residue was observed on removal of the second
substrate/bonding material combination. The bonding material
apparently did not have the flow properties needed to restore
optical clarity of the glass after a dwell time of 72 hours as
evidenced by the haze value.
Example 6
181. Example 1 was repeated except that the bonding layer was
coated on the non-hard coated surface of a 175 micron optically
clear polyester film with a 10 micron hard coat. The hard coated
polyester film was obtained from the Furon Corporation of Worcester
Mass. under the product name 007PET/0270X Hard coat. The second
substrate/bonding layer combination was applied to the abraded area
of the same abraded piece of safety glass as in Example 1 but not
on top of any other second substrate/bending layer combination. The
stress relaxation of the bonding layer was measured at 71% when
conducted the "Stress Relaxation Test Procedure Used When the
Bonding Layer is Inherently Tacky." The haze through the
polyester/bonding layer/glass laminate after 72 hours using the
procedure described in Example 1 was 5.6%. The 180.degree. peel
adhesion to glass was 457 g/2.54 cm wide. The adhesion was measured
using the "180 Degree Peel Adhesion to Glass-Procedure Used When
Bonding Layer is Inherently Tacky." No adhesive residue was
observed upon removal of the polyester/bonding layer combination.
The Visual Acuity was measured at 6 meter/6 meter.
Example 7
182. Example 1 was repeated with the following exceptions:
183. The bonding layer used was a polyhexene and the second
substrate film used was a 175-micron thick optically clear
polyester with a 10 micron hard coat. The bonding layer was coated
on the non-hard coated surface of the polyester film. The hard
coated film was obtained from the Furon Corporation of Worcester,
Mass. under the product name 007PET/0270X.
184. A bonding layer was prepared using a polyhexene with an
inherent viscosity of 3.0 dl/gram. The polyhexene was prepared
using a process described in U.S. Pat. No. 5,644,007, issued on
Jul. 1, 1997 and assigned to 3M Company, incorporated by reference
herein. The polyhexene was prepared using 0.2-0.3 g of a
Ziegler-Natta catalyst Lynx.TM. 715 per kg of monomer. Lynx.TM. 715
is TiCl.sub.4 supported on MgCl.sub.2 powder and is commercially
available from Catalyst Resources Inc. This catalyst is discussed
in Boor, Ziegler-Natta Catalysts and Polymerizations,
"Polymerization of Monomers," Ch. 19, pp. 512-562, Academic. The
conversion rate was 15%. The bonding material was coated on the
non-hard coated surface of the polyester film using a knife coater
with a gap of 15 mils. The coating was dried 10 minutes at
80.degree. C. The dry thickness of the coating was 50 microns.
185. The second substrate bonding material combination was applied
to the abraded area of the same abraded piece of safety glass as in
Example 1 but not on top of another second substrate/bonding
material combination. The stress relaxation of the bonding, layer
was measured at 59% when conducted using the "Stress Relaxation
Test Procedure Used When the Bonding Layer is Inherently Tacky."
The haze of the sample applied to the abraded panel after a 72 hour
dwell at room temperature using the procedure described in Example
1 was 5.5%. The 180.degree. peel adhesion to glass was 153g/2.54 cm
wide sample. The adhesion was measured using the "180 Degree Peel
Adhesion to Glass-Procedure Used When Bonding Layer is Inherently
Tacky". No adhesive residue was observed on removal. The Visual
Acuity was measured at 6 meter/6 meter.
Example 8
186. First, 90 grams of isooctyl acrylate, 10 grams of acrylic acid
and 0.24 gram of Irgacure.TM. 651 (available from the Ciba
Specialty Chemicals Corporation of Tarrytown N.Y.) were added to a
clear approximately 0.2 liter glass jar. A glass pipet was fastened
to a nitrogen gas line with a rubber hose and the pipet was
inserted into the solution. The nitrogen was allowed to bubble in
the solution for 10 minutes to remove the majority of oxygen in the
solution. The pipet was removed and the jar was covered with an
airtight lid. The jar was swirled in front of a UV light source for
about 10 seconds or until the Brookfield viscosity of the solution
was approximately 1500-3000 cps. (Light source= F15T8/350BL 15 watt
bulb from General Electric). To this solution 5 grams of
1,6-hexanediol diacrylate was added and stirred into the reactive
bonding material mechanically until the solution was homogenous.
The solution was allowed to sit at room temperature for 3 hours to
allow bubbles to flow to the surface.
187. The stress relaxation of the cured bonding layer was measured
at 40% using the procedure outlined for the "Stress Relaxation
Procedure When Bonding Layer is Comprised of a Reactive
Liquid".
188. To make a laminate article, approximately 5 grams of the same
solution was applied to the same 30 cm.times.30 cm glass that was
abraded with a 125 micron diamond abrasive as described in Example
1. It was applied to an area that did not have another sample
applied thereto. A corona treated 125 micron.times.15 cm.times.10
cm optically clear polyester film was applied on top of the
solution with the corona treated surface adjacent to the reactive
bonding layer. The reactive bonding layer was squeezed between the
abraded glass panel and the polyester film using a roller such that
a substantial area of the glass panel was covered by both the
bonding layer and the polyester film. The reactive bonding layer
was cured by placing the reactive glass panel under a UV light
source so light penetrated through the polyester for 5 minutes
(light source=F40/350BL--2 bulbs at a distance of 6 cm from the
sample). The haze through the polyester film/reactive bonding
layer/glass laminate was measured to be 3.5%. The 180.degree. peel
adhesion was measured using the "180.degree. Peel Adhesion to Glass
Procedure Used When Bonding Layer is comprised of a Reactive
Liquid". The 180.degree. peel adhesion to glass was measured at 170
g/2.54 cm width. The Visual Acuity through the polyester
film/reactive bonding layer/glass laminate was measured to be 6
meter/6 meter. The "Scratch Visibility" was measured to be 1.
189. The foregoing detailed description and Examples have been
given for clarity of understanding only. No unnecessary limitations
are to understood therefrom. The invention is not limited to the
exact details shown and described, for variations obvious to one
skilled in the art will be included within the invention defined by
the claims.
* * * * *