U.S. patent application number 11/095103 was filed with the patent office on 2005-08-04 for intrusion resistant glass laminates.
This patent application is currently assigned to Solutia Inc.. Invention is credited to Lu, Jun, Moran, James R., Schimmelpenningh, Julia C..
Application Number | 20050170160 11/095103 |
Document ID | / |
Family ID | 59070359 |
Filed Date | 2005-08-04 |
United States Patent
Application |
20050170160 |
Kind Code |
A1 |
Moran, James R. ; et
al. |
August 4, 2005 |
Intrusion resistant glass laminates
Abstract
Composite laminate interlayers for adhering a glass laminate
comprising a sheet of polyethylene terephthalate (PET) between
layers of plasticized polyvinyl butyral (PVB) adhesive layers,
wherein at least one of the PVB adhesive layers is stiffened, e.g.
by reduction in the amount of plasticizer, and has a glass
transition temperature greater than 35.degree. C. The PET is
preferably 0.075 to 0.25 mm (3-10 mils) thick and can have a
functional coating for reducing radiation, e.g. UV or IR or visible
light, transmission through the glass laminate. The laminate can
also comprise at least one elastomeric layer adapted to reducing
sound transmission through the glass laminate. The laminates
exhibit enhanced maximum flexural modulus of greater than about 350
Newtons/centimeter.
Inventors: |
Moran, James R.;
(Longmeadow, MA) ; Lu, Jun; (East Longmeadow,
MA) ; Schimmelpenningh, Julia C.; (North Brookfield,
MA) |
Correspondence
Address: |
Craig Lundell
Howrey Simon Arnold & White, LLP
750 Bering Drive
Houston
TX
77057
US
|
Assignee: |
Solutia Inc.
St. Louis
MO
|
Family ID: |
59070359 |
Appl. No.: |
11/095103 |
Filed: |
March 31, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11095103 |
Mar 31, 2005 |
|
|
|
09737234 |
Dec 14, 2000 |
|
|
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60170888 |
Dec 15, 1999 |
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Current U.S.
Class: |
428/214 ;
428/337; 428/437; 428/480; 428/524 |
Current CPC
Class: |
C09J 7/22 20180101; C09J
2301/124 20200801; B32B 17/10761 20130101; Y10T 428/266 20150115;
C09J 7/30 20180101; B32B 27/36 20130101; C09J 2467/006 20130101;
Y10T 428/24959 20150115; B32B 17/10174 20130101; C09J 2459/00
20130101; Y10T 428/31786 20150401; Y10T 428/24942 20150115; Y10T
428/31942 20150401; Y10T 428/3163 20150401; B32B 17/10036 20130101;
B32B 17/10005 20210101; B32B 2367/00 20130101 |
Class at
Publication: |
428/214 ;
428/337; 428/437; 428/480; 428/524 |
International
Class: |
B32B 007/02; B32B
027/06; B32B 027/36; B32B 017/10 |
Claims
What is claimed is:
1. A composite laminate interlayer for adhering a glass laminate
consisting essentially of a sheet of polyethylene terephthalate
between two layers of plasticized polyvinyl butyral adhesive
layers, wherein both layers of plasticized polyvinyl butyral have a
thickness in the range of 0.25 to 2 millimeters (10-80 mils) and
wherein at least one of said polyvinyl butyral adhesive layers has
a glass transition temperature greater than 35.degree. C. and a
tensile modulus at 25.degree. C. of greater than about 10.sup.7
Pa.
2. An interlayer according to claim 1 wherein said polyvinyl
butyral adhesive layers are of different thickness.
3. An interlayer according to claim 1 wherein said polyethylene
terephthalate sheet has a thickness greater than 0.075 millimeters
(3 mils).
4. An interlayer according to claim 1 wherein said polyethylene
terephthalate sheet has a thickness greater than 0.1 millimeters (4
mils).
5. An interlayer according to claim 1 wherein said sheet of
polyethylene terephthalate has a functional coating for reducing
radiation transmission through said glass laminate.
6. A composite laminate interlayer for adhering glass laminates
consisting essentially of a layer of polyethylene terephthalate
between two layers of plasticized polyvinyl butyral adhesive
layers, wherein the polyethylene terephthalate layer has a
thickness in the range of 0.125 to 0.254 millimeters (5-10 mils);
and each adhesive layer has a thickness in the range of 0.25 to 2
millimeter (10-80 mils) and wherein at least one layer of
plasticized polyvinyl butyral has a glass transition temperature
greater than 35.degree. C. and a tensile modulus at 25.degree. C.
of greater than about 10.sup.7 Pa.
7. A glass laminate having improved stiffness comprising in order:
(a) a first glass sheet, (b) a first layer of plasticized polyvinyl
butyral adhesive having a thickness in the range of 0.25 to 2
millimeters (10-80 mils), (c) a sheet of polyethylene terephthalate
greater than 0.075 millimeters (3 mils) thick, (d) a second layer
of plasticized polyvinyl butyral adhesive having a thickness in the
range of 0.25 to 2 millimeter (10-80 mils), and (e) a second glass
sheet, wherein said glass laminate exhibits a maximum flexural
modulus of greater than about 350 Newtons/centimeter, and wherein
at least one of the layers of plasticized polyvinyl butyral has a
glass transition temperature greater than 35.degree. C. and a
tensile modulus at 25.degree. C. of greater than about 10.sup.7
Pa.
8. A glass laminate according to claim 7 exhibiting a maximum load
before failure of at least 3000 Newtons.
9. A glass laminate according to claim 7 wherein at least one of
the layers of plasticized polyvinyl butyral has a glass transition
temperature greater than 40.degree. C.
10. A glass laminate according to claim 7 wherein said sheet of
polyethylene terephthalate has a radiation blocking coating.
11. A glass laminate having improved stiffness consisting
essentially of in order: (a) a first glass layer, (b) a first layer
of plasticized polyvinyl butyral adhesive having a thickness in the
range of 0.25 to 2 millimeters (10-80 mils), (c) a layer of
polyethylene terephthalate, (d) a second layer of plasticized
polyvinyl butyral adhesive having a thickness in the range of 0.25
to 2 millimeters (10-80 mils), (e) a second glass layer, wherein at
least one layer of plasticized polyvinyl butyral adhesive has a
glass transition temperature greater than 35.degree. C. and a
tensile modulus at 25.degree. C. of greater than about 10.sup.7
Pa.
12. A glass laminate according to claim 11 wherein said glass
laminate exhibits a maximum flexural modulus greater than about 350
Newtons/centimeter.
13. A glass laminate according to claim 11 wherein said glass
laminate exhibits a maximum flexural modulus greater than about 450
Newtons/centimeter.
14. A glass laminate according to claim 11 wherein said glass
laminate exhibits a maximum flexural modulus greater than about 550
Newtons/centimeter.
15. A glass laminate according to claim 11 wherein said glass
laminate exhibits a maximum flexural modulus greater than about 650
Newtons/centimeter.
16. A glass laminate according to claim 11 exhibiting a maximum
load before failure from a secured frame of at least 3000
Newtons.
17. A glass laminate according to claim 11 exhibiting a maximum
load before failure from a secured frame of at least 4000
Newtons.
18. A glass laminate according to claim 11 exhibiting a maximum
load before failure from a secured frame of at least 5000
Newtons.
19. A glass laminate according to claim 11 exhibiting a maximum
load before failure from a secured frame of at least 6000
Newtons.
20. A glass laminate according to claim 11 wherein said sheet of
polyethylene terephthalate has a radiation blocking coating.
Description
[0001] This application is a continuation of co-pending U.S.
application Ser. No. 09/737,234, filed Dec. 14, 2000, which in turn
claims priority from U.S. Provisional Application Ser. No.
60/170,888 filed Dec. 14, 1999.
[0002] Disclosed herein are intrusion resistant glass laminates and
composite interlayers comprising enhanced modulus polyvinyl butyral
(PVB) adhesive for making glass laminates which are especially
useful as intrusion resistant glazing for architectural and
automotive applications.
BACKGROUND
[0003] Automobile and home owners, especially those who have
experienced a vehicle break-in or theft or hurricane damage, are
increasingly interested in intrusion resistant glazing. Glass has
been identified as the weak link in the overall intrusion
resistance of vehicles and buildings. For instance, some police
reports estimate that broken glass is the entry route for at least
60% of unauthorized entry into passenger vehicles. There is also a
belief that a 10 second delay in entry is sufficient to discourage
many spontaneous thieves because the increased break-in time and
additional noise call attention to the thief. In response car
makers, at least, are replacing traditional tempered glass with
laminated glass for side and rear glazing for enhanced security.
Common automotive laminated glass can be defeated by determined
thieves who use more sophisticated tools to puncture by impact and
pull laminated glass out from its frame.
[0004] Attempts to improve the performance of glass laminates
include modifying the stiffness and/or impact resistance of the PVB
interlayer. In U.S. Pat. No. 4,814,529 Cartier et al. disclose
lightly cross-linking PVB resin to selectively increase molecular
weight of the PVB and the modulus of a plasticized sheet formed
therefrom for use in laminated safety glass assemblies. Cartier et
al. do not disclose values of modulus or construction of laminates.
In U.S. Pat. No. 5,246,764 LaPorte et al. disclose laminated
glazing with improved impact strength where mean break height for a
dropped mass of a glass laminate increased by dispersing adhesion
resistant means on the surface of PVB sheet. In U.S. Pat. No.
5,482,767 Karagiannis et al. discloses glass laminates of improved
impact resistance comprising a PVB interlayer having discrete
particles of crosslinked polyvinyl butyral integrally randomly
dispersed throughout a matrix of PVB.
[0005] Interlayer composites of polyethylene terephthalate (PET)
between layers of PVB adhesive have been used in automotive glass
laminates where a thin layer of the PET, e.g. typically up to about
0.05 millimeter (2 mils) thick, has been used as a carrier for
additional functional layers, e.g. of solar radiation blockers or
for antennas or heat strips. See for instance, U.S. Pat. Nos.
5,208,080 and 5,979,932. U.S. Pat. No. 5,091,258 discloses
composite interlayer with a 0.013 to 0.20 mm thick PET sheet coated
with a multi-layer stack of infra-red solar radiation reflecting
materials between PVB layers. U.S. Pat. Nos. 4,017,661 and
4,768,783 disclose a composite interlayer comprising a PET sheet
where a thin sheet of the PET is used as a carrier for metal layers
which can be electrically resistance heated for defrosting the
glass laminate. U.S. Pat. No. 4,973,511 discloses a laminated glass
window construction comprising a solar control film where the glass
interlayer comprised a PET sheet having on one surface at least one
thin coating of metal and at least one adjacent layer of a
dielectric material between layers of PVB; in the examples there is
disclosed the use of a 4 mil PET film between 15 mil layers of
plasticized PVB.
[0006] U.S. Pat. Nos. 5,024,895 and 5,091,258 disclose glass
laminates comprising a composite interlayer where the tensile
modulus for PET (at 21-15 C) is about 10.sup.10 Pa as compared with
about 10.sup.7 Pa for plasticized PVB of the type used in safety
glazing.
[0007] An object of this invention is to provide a more intrusion
resistant glass laminate, e.g. for use in security glazing
applications such as architectural and automotive glazing. This is
achieved by using composite interlayers comprising rigid plastic
sheet and/or stiffened PVB adhesive layers providing a higher
laminate stiffness.
SUMMARY OF THE INVENTION
[0008] This invention provides a composite laminate interlayer for
use in manufacturing intrusion resistant glass laminates having a
higher laminate stiffness. Such laminates comprise an interlayer
having at least one layer of high stiffness, plasticized PVB. In
one aspect of the invention high stiffness in plasticized, PVB is
advantageously provided by reducing the level of plasticizer as
indicated by a rise in glass transition temperature (Tg) of the
plasticized PVB, e.g. about 2 to 3.degree. C. above typical values
for a commercial application. For instance, for automotive
applications, where plasticized PVB sheet typically has a Tg of
about 30-33.degree. C., high stiffness PVB of this invention will
have a Tg of at least 35.degree. C. Glass laminates of this
invention preferably have a maximum flexural modulus of at least
350 Newtons/centimeter (N/cm).
[0009] Another aspect of this invention provides a composite
laminate interlayer comprising a layer of PET between layers of
plasticized PVB adhesive where at least one of the PVB layers
exhibits enhanced stiffness. Preferably, the PET has a thickness in
the range of 0.125 to 0.254 millimeters (5-10 mils). Another aspect
of this invention provides interlayer composites with other
functional layers, e.g. sound dampening elastomer layers or
radiation blocking layers.
[0010] Another aspect of this invention provides intrusion
resistant glass laminates comprising a composite interlayer of this
invention exhibiting high stiffness of at least 350 N/cm. Other
aspects of the invention will be clear from the following detailed
description of preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a typical plot of tan delta v. temperature used to
determine glass transition temperature of plasticized PVB.
[0012] FIGS. 2, 3, and 4 are schematic sectional views of glass
laminates according to the invention.
[0013] FIGS. 5A and 5B illustrates a mounting frame for testing
glass laminates according to this invention.
[0014] FIGS. 6 and 7 are graphical representations of "load v.
displacement" response determined from a ram penetrating a glass
laminate of this invention; such "load v. displacement" curve is
useful for determining flexural modulus.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] As used herein the term "flexural modulus" of a laminate is
slope of the "load v. displacement" curve defined as the measured
load, e.g. expressed in Newtons (N), of 180 mm diameter
hemispherical ram is driven into the laminate at a speed of 125
mm/minute per distance of ram penetration, e.g. expressed in
centimeters (cm), before failure or yield, e.g. as determined by a
reduction in load with increased penetration.
[0016] As used herein the term "maximum flexural modulus" of a
laminate is defined as the highest slope of the "load v.
displacement" curve over a range of 2 centimeters of ram
displacement before failure.
[0017] As used herein glass transition temperature (Tg) of
plasticized PVB is determined by rheometric dynamic analysis using
the following procedure. Plasticized PVB sheet is molded into a
sample disc of 25 millimeters (mm) in diameter. The PVB sample disc
is placed between two 25 mm diameter parallel plate test fixtures
of a Rheometrics Dynamic Spectrometer II. The PVB sample disc is
tested in shear mode at an oscillation frequency of 1 Hertz as the
temperature of the PVB sample is increased from -20 to 70.degree.
C. at a rate of 2.degree. C./minute. The position of the maximum
value of tan delta (damping) plotted as dependent on temperature is
used to determine Tg as illustrated in FIG. 1. Experience indicates
that the method is reproducible to within +/-1.degree. C.
Commercially used PVB typically has a Tg in the range of
30-33.degree. C.
[0018] PVB resin is produced by known aqueous or solvent
acetalization processes reacting PVOH with butyraldehyde in the
presence of acid catalyst, followed by neutralization of the
catalyst, separation, stabilization and drying of the resin. It is
commercially available from Solutia, Inc. as Butvar RTM resin. PVB
resin typically has a weight average molecular weight greater than
70,000, preferably about 100,000 to 250,000, as measured by size
exclusion chromatography using low angle laser light scattering. On
a weight basis PVB typically comprises less than 22%, preferably
about 17 to 19% hydroxyl groups calculated as polyvinyl alcohol
(PVOH); up to 10%, preferably 0 to 3% residual ester groups,
calculated as polyvinyl ester, e.g. acetate, with the balance being
acetal, preferably butyraldehyde acetal, but optionally including
aminor amount of acetal groups other than butyral, for example
2-ethyl hexanal as disclosed in U.S. Pat. No. 5,137,954.
[0019] The PVB resin of the sheet is typically plasticized with
about 20 to 80 and more commonly 25 to 45 parts plasticizer per
hundred parts of resin. Plasticizers commonly employed are esters
of a polybasic acid or a polyhydric alcohol. Suitable plasticizers
are triethylene glycol di-(2-ethylbutyrate), triethyleneglycol
di-(2-ethylhexanoate), tetraethyleneglycol diheptanoate, dihexyl
adipate, dioctyl adipate, mixtures of heptyl and nonyl adipates,
dibutyl sebacate, polymeric plasticizers such as the oil-modified
sebacic alkyds, and mixtures of phosphates and adipates such as
disclosed in U.S. Pat. No. 3,841,890 and adipates and alkyl benzyl
phthalates as disclosed in U.S. Pat. No. 4,144,217. Also mixed
adipates made from C.sub.4 to C.sub.9 alkyl alcohols and cyclo
C.sub.4 to C.sub.10 alcohols as disclosed in U.S. Pat. No.
5,013,779. C.sub.6 to C.sub.8 adipate esters such as hexyl adipate
are preferred plasticizers. A more preferred plasticizer is
ethylene glycol di(2-ethylhexanoate). The amount of plasticizer
used is a convenient means to modifying and controlling the
stiffness of the PVB. A useful surrogate property for stiffness is
Tg which is directly related to the level of plasticizer. The
plasticized PVB sheet used in the laminates of this invention will
have a Tg of at least 35.degree. C. or higher, i.e. at least
37.degree. C., preferably at least 39.degree. C. or higher, i.e. at
least 41.degree. C., and most preferably at least 43.degree. C. or
higher, i.e. at least 45.degree. C.
[0020] The high Tg PVB of this invention will have a sufficiently
low tackiness at typical processing conditions to inherently avoid
undesired adhesion, e.g. in stacks of PVB, prior lamination. Since
the laminates of this invention will comprise at least one layer of
enhanced stiffness PVB, it is expected that at least one or more
other layers of PVB could comprise standard, commercially-used,
plasticized PVB of traditional stiffness and Tg. Such standard PVB
typically has a Tg in the range of 32-33.degree. C. and is
sufficiently inherently tacky as require the use of an adhesion
control agent to reduce tackiness to facilitate stacking of PVB
layers with minimal adhesion prior to construction of a laminate.
Useful adhesion control agents are disclosed in U.S. Pat. Nos.
5,342,653 and 5,547,736 (anti-adhesion projections), U.S. Pat. No.
4,999,078 (the addition of ionomer groups), U.S. Pat. No. 5,618,863
(the addition of multivalent, metal salt of a organic acid, e.g.
magnesium 2-ethyl butyrate, as an adhesion control agent) and U.S.
Pat. Nos. 5,425,977, 5,455,103 and 5,595,818 (use of a non-uniform
surface).
[0021] As disclosed in U.S. Pat. No. 5,618,863 it is also often
useful or desirable to incorporate a UV absorber in PVB. In
addition to plasticizer, optional UV absorber and adhesion control
agent, PVB sheet may contain other performance-enhancing additives
such as pigments or dyes for coloring all or part of the sheet,
antioxidants and the like. PVB sheet is prepared by mixing combined
plasticizer and other additives (e.g. UV-absorber, adhesion control
agent and the like) with PVB resin and forcing the mixture under
pressure through a die opening to form a sheet. Thickness of the
extruded sheet can range from 0.13 to 2 mm, typically about 0.4 to
about 1.6 mm thick to provide the desired performance in the glass
laminate.
[0022] PET sheet for use in the composite interlayer of this
invention is preferably biaxially stretched to improve strength and
has been heat stabilized to provide low shrinkage characteristics
when subjected to elevated temperatures (i.e. less than 2%
shrinkage in both directions after 30 min. at 150.degree. C.). The
tensile modulus (at 21-25.degree. C.) of polyethylene terephthalate
is about 10.sup.10 Pa as compared with about 10.sup.7 Pa for
plasticized polyvinyl butyral of the type used in safety glazings.
To facilitate bonding of PVB to PET a coating and/or surface
treatment can be applied to PET film as disclosed in European
Patent 157030 B1, and U.S. Pat. No. 4,732,814, incorporated herein
by reference, which discloses plasma treatment of biaxially
stretched polyester to improve adhesion. A preferred method for
treating the surface of PET film includes deposition of a thin
layer of carbon by vacuum sputtering as disclosed by Kittler in
U.S. Pat. No. 4,865,711 (incorporated herein by reference).
[0023] Composite interlayers according to this invention are
prepared by known procedures. See for instance, U.S. Pat. Nos.
4,973,511, 5,024,895 and 5,091,258 (incorporated herein by
reference) for methods for laminating plasticized PVB to
surface-treated PET sheet. Because final bonding conditions will be
experienced when the interlayer is bonded to glass, the degree of
bonding of PVB to PET in the composite interlayer is not critical.
Because at least one layer of plasticized PVB in the composite
interlayers of this invention will have a Tg higher than
convention, a person of ordinary skill in the art will appreciate a
need to raise the processing temperature of the PVB sheet by an
amount corresponding to the elevation in Tg. Suitable temperatures
for bonding PVB to PET will typically be in the range of 50 to
120.degree. C. The PET/PVB composites can be pressed, e.g. in a nip
roller, to improve adhesion.
[0024] Glass laminates using sheets of the invention are prepared
by known procedures, e.g. as disclosed in U.S. Pat. Nos. 5,024,895;
5,091,258; 5,145,744; 5,189,551;5,264,058 and 5,529,654 (all of
which are incorporated herein by reference). Composite interlayer
is placed between two sheets of glass and heated under vacuum to a
temperature in the range of about 85 to 120.degree. C. for about 10
to 30 minutes, depending on temperature, to remove air from between
the layers of the laminate. After de-airing the laminate is
preferably heated in an autoclave at elevated temperature (about 90
to 165.degree. C.) and pressure (about 1000 to 2000 kPa) for
sufficient time to firmly bond the layers of the laminate.
Non-autoclave methods as disclosed in U.S. Pat. No. 5,536,347 may
are also useful, e.g. for plasticized PVB having only moderate
increases in Tg.
[0025] Referring to FIG. 2 a glass laminate comprises glass sheets
201 and 205 which can comprise float glass or tempered glass
typically in the range of 1 to 20 millimeters (mm) thick,
preferably in the range of 1-10 mm thick. Between and bonded to the
glass sheets is a composite interlayer comprising a PET sheet 203
between layers of plasticized PVB adhesive 202 and 204. The PET
sheet is biaxially-oriented and can be in the range of 0.025 to
0.25 mm thick (1 to 10 mils), preferably at least 0.125 mm thick.
For desired adhesion to the PVB, the surface of the PET is
preferably modified, e.g. by roughening of the surface or by
chemical modification of the material at the surface. Such
modification can be effected by flame treatment, chemical
oxidation, corona discharge, carbon sputtering, plasma treatment in
vacuum or in air or other treatments well known to those of
ordinary skill in the art. A preferred surface treatment is plasma
treatment in air. The PVB is plasticized, most preferably with
triethylene glycol di(2-ethylhexanoate), in an amount to provide a
Tg of at least 35.degree. C. In the laminates of this invention
layers 202 and 204 can be similar, e.g. comprise plasticized PVB
having a Tg of at least 35.degree. C. Alternatively, layers 202 and
204 can be different, e.g. plasticized PVB layer 202 can comprise a
conventional PVB layer having a Tg of about 33.degree. C. and PVB
layer 202 can comprise a toughened PVB layer having a Tg of at
least 35.degree. C.
[0026] With further reference to FIG. 2 in alternative embodiments
of the invention the PET layer 203 can be replaced with an
alternative high modulus layer such as a plasticized PVB sheet with
higher stiffness than the PVB comprising layers 202 and 204.
Alternatively, layer 203 can be substituted with a thick, e.g. up
to 1 to 2 mm, sheet of plasticized PVB having a Tg of about
33.degree. C. with layers 202 and 204 comprising plasticized PVB
having a Tg of 35.degree. C. or higher. In a further alternative
embodiment, one or both of the plasticized PVB layers 202 and 204
can be composites of high modulus and low modulus plasticized PVB,
e.g. a sheet of plasticized PVB having a Tg of about 33.degree. C.
adhered to a sheet of PVB having a Tg of 35.degree. C. or higher.
Such composites when used in an interlayer having a PET sheet
provide a balance of properties such as modulus and toughness over
a wider temperature range of use than a monolithic sheet.
[0027] In yet another embodiment of this invention any or all of
the plasticized PVB layers can comprise a composite of high and low
stiffness plasticized PVB, e.g. a layer of about 0.4 to 1.6 mm
thick having a Tg of about 33.degree. C. adhered to a layer of
about 0.25 to 1.6 mm thick having a Tg of 35.degree. C. or higher.
The orientation of such composite layers of plasticized PVB in the
glass composite can vary. Accordingly, in some cases it is
preferred to orient composite plasticized PVB layers with the high
modulus plasticized PVB in contact with the glass. In other cases
it may be preferred to have the low modulus plasticized PVB in
contact with the glass.
[0028] In FIG. 3 there is shown an alternative embodiment where the
laminate further comprises a an additional layer 306 which can be a
sound attenuating elastomer layer as disclosed in U.S. Pat. No.
5,796,055 (incorporated herein by reference) or a radiation
blocking layer, e.g. comprising a composite of one or more layers
of metal or metal oxide deposited onto the PET layer as disclosed
in any of U.S. Pat. Nos. 5,024,895, 5,091,258 or 5,932,329 (the
disclosures of all four patents being incorporated herein by
reference).
[0029] In FIG. 4 there is shown another alternative embodiment
where the laminate comprises additionally comprises both a sound
attenuating elastomer layer 406 and separate a radiation blocking
layer 407, e.g. comprising a stack of metal and/or metal oxide
layers deposited onto the PET layer 203.
[0030] FIGS. 5A and 5B show a test frame 501 comprising a
rectangular base 502 having a rectangular opening and supporting
beams 503 which are covered with 3 mm thick rubber strips 504. A
sheet of laminated glass 505 having overall dimensions of
45.times.60 cm (18.times.24 in) will rest on the support beams 503
with an 11 mm bite. Four angle-shaped holders 506 with a 3 mm thick
rubber coating 507 overlap the top edge of the glass laminate with
a 5-6 mm bite on all four edges of the glass laminate. Each holder
506 is secured to the frame by two C-clamps 508 (one of eight is
shown) located at a distance from each corner equivalent to about
one-fourth of the length of the side of the laminate. The frame is
positioned below a 180 mm diameter hemispherical ram head 509 which
is driven into the glass laminate at a speed of 125 mm/minute. The
load and distance of ram travel from impact with the glass laminate
is recorded to generate a "load v. displacement" response curve as
illustrated in FIGS. 6 and 7. The ratio of load to ram displacement
represents flexural modulus of the laminate.
[0031] The following Examples illustrate and do not limit or
restrict the invention and are illustrated using the following
materials.
[0032] 3GEH: triethylene glycol di(2-ethylhexanoate)
plasticizer
[0033] Glass: 2.2 mm thick annealed float glass.
[0034] PET1: 0.1 mm (4 mil) thick PET sheet, biaxially oriented and
carbon sputtered.
[0035] PET2: 0.177 mm (7 mil) thick PET sheet, biaxially oriented
and carbon sputtered.
[0036] PVB1: 0.38 mm (15 mil) thick plasticized PVB containing 38
phr 3GEH and having a Tg of about 32.degree. C.
[0037] PVB2: 0.76 mm (30 mil) thick plasticized PVB containing 38
phr 3GEH and having a Tg of about 32.degree. C.
[0038] PVB3: 1.14 mm (45 mil) thick plasticized PVB containing 38
phr 3GEH and having a Tg of about 32.degree. C.
[0039] PVB4: 1.52 mm (60 mil) thick plasticized PVB containing 38
phr 3GEH and having a Tg of about 32.degree. C.
[0040] PVB5: 0.76 mm (30 mil) thick plasticized PVB containing 22
phr 3GEH and having a Tg of about 45.degree. C.
[0041] PVB6: 0.38 mm (15 mil) thick plasticized PVB containing 30
phr 3GEH and having a Tg of about 38.degree. C.
[0042] PVB7: 0.76 mm (30 mil) thick plasticized PVB containing 30
phr 3GEH and having a Tg of about 38.degree. C.
[0043] IONOMER: 1.52 mm (60 mil) thick ionomer sheet obtained from
E.I. duPont de Nemours & Company under the trademark Surlyn
SPK.
EXAMPLES 1-15
[0044] Glass laminates about 45.times.60 cm (18.times.24 in) were
constructed of the materials indicated in Table 1.
1TABLE 1 Laminate No. Layer Assembly 1 glass/PBV2/glass 2
glass/PVB3/glass 3 glass/PVB4/glass 4 glass/PVB1/PET2/PVB1/glass 5
glass/PVB5/PVB5/glass 6 glass/PVB7/PET2/PVB7/glass 7
glass/PVB6/PET2/PVB6/glass 8 glass/PVB7/PET1/PVB7/glass 9
glass/PVB2/PET1/PVB2/glass 10 glass/PVB6/PET1/PVB6/glass 11
glass/PVB5/PET2/PVB5/glass 12 glass/IONOMER/glass 13
glass/PVB2/PET2/PVB2/glass 14 glass/PVB5/glass 15
glass/PVB1/PVB5/PVB1/glass
[0045] The laminates were evaluated for impact resistance by
striking with a 9.5 kilogram hammer-head at the end of a 1400 mm
pendulum arm from a drop height of 700 mm according to British
Standard BS AU 209, Part 4a modified in that the glass laminate was
mounted in a vertically oriented test frame of the type shown in
FIG. 5A; the hammer was set to strike at five points of a diamond
pattern measuring 70 mm on a square side (in sequence, the top,
left center, center, right center and bottom). After hammer impact
the laminates were deformed in the range of 2.5 to 35 mm (0.1 to
1.4 inches) with cracked glass but intact interlayer. After
pendulum impact testing the laminates were subjected to ram head
penetration testing to measure flexural modulus. The "load v.
resistance" curves for the laminates of examples 6 to 15 are
reported in FIGS. 6 and 7 as indicated by example number. The
maximum flexural modulus for certain of the laminates in reported
in Table 3.
2 TABLE 3 Laminate No. Maximum Flexural Modulus, N/cm 1 166 2 218 3
253 4 662 5 615 6 956 7 730 8 687 9 589 10 626 11 1043 12 594 13
698 14 388 15 359
[0046] The preceding description is set forth for purposes of
illustration only and is not to be taken in a limited sense.
Various modifications and alterations will be readily apparent to
persons skilled in the art. It is intended, therefore, that the
foregoing be considered as exemplary only and that the scope of the
invention be ascertained from the following claims.
* * * * *