U.S. patent application number 10/786367 was filed with the patent office on 2004-09-30 for interlayer for laminated glass and laminated glass.
This patent application is currently assigned to SEKISUI CHEMICAL CO., LTD.. Invention is credited to Nakajima, Minoru, Sannomiya, Isei.
Application Number | 20040191482 10/786367 |
Document ID | / |
Family ID | 27573382 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040191482 |
Kind Code |
A1 |
Nakajima, Minoru ; et
al. |
September 30, 2004 |
Interlayer for laminated glass and laminated glass
Abstract
The present invention provides an interlayer for a laminated
glass which does not give rise to the moir phenomenon even when the
arrangement and pitch of its embossments are orderly, hence
providing for good workability in cutting and laminating operations
and good deaeration in preliminary contact bonding, thus insuring
the production of a laminated glass of high quality with a minimum
of rejects for reasons of air bubbles, and a laminated glass
containing said interlayer. The invention also provides an
interlayer for a laminated glass which provides for good deaeration
without a risk for premature marginal sealing even if the
temperature at initiation of deaeration at preliminary contact
bonding is not critically controlled and which does not require
raising of temperature for achieving a marginal seal of the
glass-interlayer assembly, and a laminated glass containing said
interlayer.
Inventors: |
Nakajima, Minoru; (Koka-gun,
JP) ; Sannomiya, Isei; (Koka-gun, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
SEKISUI CHEMICAL CO., LTD.
|
Family ID: |
27573382 |
Appl. No.: |
10/786367 |
Filed: |
February 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10786367 |
Feb 26, 2004 |
|
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10019656 |
Feb 12, 2002 |
|
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10019656 |
Feb 12, 2002 |
|
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PCT/JP00/04383 |
Jul 3, 2000 |
|
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Current U.S.
Class: |
428/156 |
Current CPC
Class: |
B29C 2059/023 20130101;
Y10T 428/24612 20150115; B32B 17/10761 20130101; B29C 59/022
20130101; B29C 59/04 20130101; Y10T 428/3163 20150401; Y10T
428/31518 20150401; Y10T 428/2457 20150115; Y10T 428/24355
20150115; Y10T 428/24479 20150115; Y10T 428/24628 20150115; B29K
2029/00 20130101; B32B 17/10587 20130101 |
Class at
Publication: |
428/156 |
International
Class: |
B32B 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 1999 |
JP |
11/187627 |
Jul 15, 1999 |
JP |
11/201747 |
Aug 2, 1999 |
JP |
11/218796 |
Dec 1, 1999 |
JP |
11/342172 |
Dec 7, 1999 |
JP |
11/347675 |
Jan 6, 2000 |
JP |
2000/900 |
Jan 13, 2000 |
JP |
2000/4685 |
Feb 3, 2000 |
JP |
2000/26652 |
Claims
1. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, a pitch
of embossments on one side being different from a pitch of
embossments on the other side.
2. The interlayer for a laminated glass according to claim 1,
wherein concave portions on at least one side are continual.
3. The interlayer for a laminated glass according to claim 1 or 2,
wherein bottoms of concave portions on at least one side are
continual.
4. The interlayer for a laminated glass according to any one of
claims 1 to 3, wherein the pitch (L1) of embossments on one side
and the pitch (L2) of embossments on the other side satisfy the
relation of (L1)<(L2), and the proportion of existence of a
convex portion on the other side within the range (L1.times.0.25)
of before and after a position of a convex portion on one side is
not more than 50% of the number of convex portions on one side.
5. The interlayer for a laminated glass according to any one of
claims 1 to 4, wherein concave portions at least one side are
provided in a linear pattern.
6. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, said
concave portions on at least one side having a trough-like geometry
with a continual bottom while said convex portion on the same side
having a plateau-forming top surface.
7. The interlayer for a laminated glass according to claim 6,
wherein fine concave and convex portions are provided on the
plateau-forming top surface of the convex portion.
8. The interlayer for a laminated glass according to claim 7,
wherein a surface roughness Ra of the plateau-forming top surface
is not less than 2.5 .mu.m.
9. The interlayer for a laminated glass according to claim 7 or 8,
wherein the surface roughness Ra of the plateau-forming top surface
is not less than 3.0 .mu.m.
10. The interlayer for a laminated glass according to any one of
claims 6 to 9, wherein a width of the plateau-forming top surface
is not less than 20% of a pitch of convex portions.
11. The interlayer for a laminated glass according to any one of
claims 6 to 10, wherein the width of the plateau-forming top
surface is constant.
12. The interlayer for a laminated glass according to any one of
claims 6 to 11, wherein the width of the plateau-forming top
surface is random.
13. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, said
concave portions on at least one side having a trough-like
geometry, and segmenting walls being formed in said trough-like
geometry.
14. The interlayer for a laminated glass according to claim 13,
wherein a height of the segmenting wall is smaller than a depth of
the trough.
15. The interlayer for a laminated glass according to claim 12 or
14, wherein segmenting walls are arranged at equal intervals.
16. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, said
concave portions on at least one side having a trough-like geometry
and being not on one and the same level, and a ratio of a surface
roughness (Rz) and a surface roughness (Rzv) of a negative model
being Rzv/Rz.gtoreq.0.25 on at least one side.
17. The interlayer for a laminated glass according to claim 16,
wherein troughs are provided in a linear configuration.
18. The interlayer for a laminated glass according to claim 16
wherein troughs are provided in a grid configuration.
19. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, said
concave portions on at least one side having a continual
trough-like geometry, and said convex portion on the same side
having segmenting troughs while a bottom of said segmenting trough
being not on one and the same level as a bottom of the continual
trough-like geometry of said concave portion.
20. The interlayer for a laminated glass according to claim 19,
wherein the trough-like geometry of the concave portion and
segmenting troughs of said convex portion are provided in a grid
configuration.
21. The interlayer for a laminated glass according to claim 19,
wherein the trough-like geometries of the concave portion and
segmenting troughs of said convex portion are provided in a random
configuration.
22. The interlayer for a laminated glass according to any one of
claims 19 to 21, wherein a depth of segmenting troughs of the
convex portion are uniform.
23. The interlayer for a laminated glass according to any one of
claims 19 to 21, wherein a depth of segmenting troughs of the
convex portion are random.
24. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, at
least one side being provided with concave troughs, and an angle
between said concave trough and a direction of extrusion of said
thermoplastic resin sheet being less than 25.degree..
25. An interlayer for a laminated glass which comprises a
thermoplastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof, said
concave portions on at least one side having a trough-like
geometry, and said trough-like geometry being constant in sectional
area while having a depth distribution of troughs having a depth of
not less than 5% of the maximum trough depth.
26. The interlayer for a laminated glass according to claim 25,
wherein troughs having the depth of-not less than 5% of the maximum
trough depth are provided at a pitch of not more than 10 mm.
27. The interlayer for a laminated glass according to claim 25 or
26, wherein the trough-like geometry is provided in parallel with
the direction of flow of the interlayer for a laminated glass.
28. The interlayer for a laminated glass according to any one of
claims 1 to 23 and 25 to 27, wherein the thermoplastic resin sheet
is a plasticized polyvinyl acetal resin sheet.
29. A laminated glass obtainable by interposing the interlayer for
a laminated glass according to any one of claims 1 to 23 and 25 to
28 between at least one pair of glass sheets and consolidating them
into an integral unit.
Description
[0001] This is a divisional of application Ser. No. 10/019,656
filed Feb. 12, 2002; which is a .sctn.371 National Stage
Application of PCT Application No. PCT/JP00/04383 filed Jul. 3,
2000; the disclosure of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to an interlayer for a
laminated glass providing for improved deaeration and a laminated
glass comprising the same.
BACKGROUND ART
[0003] The laminated glass manufactured by interposing an
interlayer comprising a sheet made of a thermoplastic resin such as
plasticized polyvinyl butyral between glass sheets and bonding them
together into an integral unit is in broad use for glazing the
windows of automobiles, aircraft, and buildings.
[0004] When such a laminated glass is subjected to an external
impact, the glass may break up but the interlayer sandwiched
between the component glass sheets will not readily be destroyed
and even after breakage, the glass remains glued to the interlayer
so that its fragments will not be scattered. Therefore, the bodies
of men in the vehicle or building are protected against the injury
by fragments of the broken glass.
[0005] Such a laminated glass is usually manufactured by
interposing an interlayer between glass sheets, drawing the whole
over a nip roll or placing it in a rubber bag and evacuating the
bag to effect preliminary contact bonding with concurrent removal
of the residual air entrapped between the glass and the interlayer
under suction, and finally carrying out final contact bonding at
elevated temperature and pressure in an autoclave.
[0006] The interlayer mentioned above is required to satisfy not
only the basic performance requirements such as good clarity,
bondability, bullet resistance, weather resistance, etc. but also
the requirement that it does not undergo blocking during storage,
the requirement that it provides for good workability in the
insertion thereof between glass sheets, and the requirement that it
lends itself to efficient deaeration in preliminary contact bonding
so that the formation of bubbles by entrapment of air may be
precluded.
[0007] To satisfy the above requirements, it is common practice to
provide both surfaces of an interlayer with many embossment
patterns comprising fine convex portions and concave portions. As
the geometry of such concave and convex portions, there are
disclosed a variety of embossment geometries each containing a
multiplicity of concave portions and the corresponding multiplicity
of concave portions, and a variety of geometries each containing a
multiplicity of ridges and the corresponding multiplicity of
troughs.
[0008] The morphological parameters of an embossment design, such
as coarseness, arrangement and relative size, have also been
explored and Japanese Kokoku Publication Hei-1-32776 discloses "a
thermoplastic resin interlayer comprising a flexible thermoplastic
resin film or sheet having a fine concavo-convex (embossed) surface
pattern for use as an interlayer for lamination characterized in
that at least one side of which is provided with a multiplicity of
discrete protruded portions integral with the film or sheet, with
all the concave portions complementary to said protruded portions
forming a continuum on the same level."
[0009] However, when such an orderly embossment pattern is
generally formed on both sides of the interlayer, the mutual
interference of the diffracting surfaces gives rise to a
streaks-like diffraction image known generally as the "moir
phenomenon".
[0010] Furthermore, since the conventional embossment pattern is
generally provided in a random fashion by using sand blasted roll,
it hardly provides for sufficient deaeration.
[0011] The moir phenomenon mentioned above is not only undesirable
from appearance points of view but the attention-distracting change
of the interference fringes causes an eye strain and motion
sickness-like symptoms in the working personnel involved in
interlayer cutting and laminating operations, thus leading to the
problem of poor workability. Moreover, even in the case of an
interlayer provided with an orderly embossment pattern only on one
side, the operation involving the stacking of a plurality of
interlayer sheets causes appearance of the moir phenomenon, thus
detracting from workability in a similar manner.
[0012] The moir phenomenon is more liable to occur when the
arrangement and pitch of the embossed pattern formed on the surface
of an interlayer are more orderly, and in cases where the
arrangement is such that the distance between at least two points
of the convex portions of respective embossments is constant or
where the arrangement of the embossment pattern on both sides of
the interlayer are identical, the moir phenomenon occurs in most
instances.
[0013] Therefore, such embossment patterns as a grid pattern, a
stripe pattern, and a radiant pattern having a constant angular
pitch may be mentioned as representative embossment patterns liable
to give rise to the moir phenomenon.
[0014] To overcome this disadvantage of the above moir phenomenon
and the associated deterioration of workability, Japanese Kokai
Publication Hei-5-294679, for instance, discloses "a method which
comprises providing the surface of an interlayer with a
multiplicity of protruded portions in a controlled pattern and
further with an embossment pattern of convex portions finer than
these protruded portions in a random pattern."
[0015] It is true that the above method contributes in a
considerable measure to attenuation of the above moir phenomenon
but since the embossment pattern of finer convex portions is formed
to extend not only to surfaces of the larger protruded portions but
also surfaces not formed with the larger protruded portions, the
pooling of air occurs in concave portions of the embossment between
the finer convex portions so that the deaeration in preliminary
contact bonding becomes insufficient as a disadvantage.
[0016] Further, Japanese Kohyo Publication Hei-9-508078 discloses
an interlayer having embossment patterns each having an orderly
array of troughs, the pattern on one side being displaced from that
on the other side by not less than 25 degrees, more preferably by
90 degrees, to thereby obviate the moir phenomenon.
[0017] It is known, in the above technology, that the linear
designs displaced by 90 degrees for obviating the moir phenomenon
can be imparted by the heat transfer technique using a roll having
engraved lines of 45 degrees. However, the larger the angle of
engraved lines of the roll is, the less easy is the heat transfer
to be effected. Generally speaking, a pattern of longitudinally
parallel lines with respect to the flow of transfer can be most
easily formed and a pattern of transverse lines requires transfer
temperature control as well as a high transfer pressure.
[0018] Furthermore, in the above technology, unless the temperature
at initiation of deaeration in preliminary contact bonding is
critically controlled, a premature sealing of the marginal part of
the glass-interlayer assembly (e.g. glass/interlayer/glass), i.e.
premature marginal sealing, takes place, with the result that the
deaeration of the central part of the assembly becomes still more
inadequate.
[0019] As a measure to prevent the above premature marginal
sealing, there is known the method which comprises controlling the
temperature at initiation of deaeration according to the size of
troughs to thereby prevent said premature sealing at the pressure
bonding of the assembly or the method which comprises increasing
the coarseness of embossment. However, there is the problem that in
order to achieve a positive marginal seal of the laminate, the
temperature for preliminary contact bonding must be considerably
raised.
[0020] Furthermore, if the linear designs on both sides of the
interlayer are made parallel from moldability considerations, the
problem will arise that the handleability of the interlayer
particularly in terms of self-adhesiveness is adversely affected,
i.e. the self-adhesion of the interlayer is increased.
[0021] In fact, the above prior art interlayer has been fairly
improved in the tendency toward blocking during storage, handling
workability, and the efficiency of deaeration in preliminary
contact bonding but in the production of a laminated glass having a
large surface area or a laminated glass with a large radius of
curvature or in carrying out deaeration under the stringent
conditions imposed by circumstances calling for increased
productivity of laminated glass, for instance, there is the problem
that the deaeration and sealing effects are not so satisfactory as
desired.
[0022] Thus, when deaeration is to be carried out under such
stringent conditions, it is difficult, in particular, to establish
a uniform seal between the sheet glass and interlayer all over the
area and, hence, deaeration and sealing become insufficient, with
the result that in the final contact bonding performed under heat
and pressure in an autoclave, pressurized air infiltrates through
the seal defect to form air bubbles between the glass and the
interlayer, thus frustrating to produce a laminated glass of high
transparency.
[0023] The problem of such a seal defect can be resolved to a
certain extent by strictly controlling preliminary contact bonding
conditions within a certain very narrow range but the compatible
temperature range is so narrow that the incidence of rejects due to
air bubble formation is increased.
[0024] Moreover, when a laminated glass is manufactured using an
interlayer such that both the geometry of embosses and the level of
depressions are uniform all over as described in the above
disclosure, the variation in thickness of the very interlayer film
and the pair thickness difference consisting of the difference in
thickness or the difference in the radius of curvature of the glass
to be laminated cannot be sufficiently absorbed.
[0025] In addition, in the case of the prior art interlayer, it is
necessary to prepare a large number of embossing rolls having
different designs corresponding to various processing needs of
users and manufacture many kinds of interlayer films embossed to
various three-dimensional patterns compatible with the respective
users' processing conditions, this being inefficient from
productivity points of view.
[0026] Furthermore, when the preliminary contact bonding process
involving deaeration by draw deaeration is compared with the
process involving deaeration by vacuum deaeration, there is a
marked difference in the conditions of deaeration, viz. whereas
deaeration is effected at an elevated pressure in the former
process, it is effected at a negative pressure in the latter
process, so that in establishments having only one kind of
equipment, there are cases in which preliminary contact bonding
cannot be carried out.
[0027] As mentioned hereinbefore, the preliminary contact bonding
technology involving deaeration is generally classified into a draw
deaeration method in which the glass-interlayer assembly is drawn
over a rubber roll and a vacuum deaeration method in which the
assembly is placed in a rubber bag and subjected to a negative
pressure to bleed air from the margin of the glass-interlayer
assembly.
[0028] In the deaeration method involving the use of a negative
pressure, the process starts with placing the
glass/interlayer/glass assembly in a sufficiently cooled (e.g.
20.degree. C.) rubber bag and starting deaeration. The vacuum hold
time is set to about 10 minutes and after the air is sufficiently
removed from the whole glass/interlayer/glass assembly, the
temperature is raised to heat the assembly to about 110.degree. C.
By this procedure, the interlayer and glass are bonded almost
completely tight. Then, the assembly is cooled to the neighborhood
of room temperature and the preliminary laminated glass thus
obtained is taken out and transferred to the final contact bonding
stage.
[0029] When the vacuum deaeration method is adopted in the
preliminary contact bonding stage, which comprises the above cycle
of heating and cooling, it is necessary for enhanced productivity
to set the initial temperature within the rubber bag at a high
level and set the ultimate temperature at a low level.
[0030] However, when the initial temperature within the rubber bag
is set high, the marginal part of the assembly is the first to
succumb to the pressure of contact bonding so that the air in the
central part is prevented from escaping efficiently but remains
entrapped. If the deaeration is sufficient in the preliminary
contact bonding stage, any residual air, which is small in amount,
is allowed to dissolve in the interlayer in the final contact
bonding stage (e.g. 130.degree. C..times.1.3 MPa.times.1 hr), with
the result that a transparent laminated glass can be obtained.
However, if the residual amount of air is large, the air will not
be completely dissolved in the final contact bonding stage so that
air bubbles appear in the product laminated glass. On the other
hand, if the ultimate temperature is set too low, an incomplete
seal occurs locally in the marginal region and as the pressurized
air finds its way into such localities in the final contact bonding
stage, air bubbles are produced in the product laminate.
[0031] Another factor contributory to the above phenomenon is that,
in a laminated glass of the glass/interlayer/glass construction,
there occur areas where one of the glass sheets is urged toward the
other glass sheet and areas where one of the glass sheets is urged
away from the other glass sheet depending on the accuracy of glass
bending and the way in which the gravity of glass acts.
[0032] The geometry of embossed surface irregularities proposed so
far includes random geometries (a hill and a valley are
alternating) and orderly geometries comprising quadrangular
pyramids or triangular pyramids. In addition, as applicable to the
vacuum deaeration method, Japanese Kohyo Publication Hei-9-508078
teaches that providing a route for escape of air by means of
troughs is effective in preventing the premature sealing in the
course of deaeration.
[0033] This method, however, has the disadvantage that while the
initial temperature within the rubber bag can be set high, the
ultimate temperature must also be set high and if the ultimate
temperature is set low, the infiltration of air will occur in the
final contact bonding stage to cause air bubbles. Thus, in the case
of the conventional random embossments, the heating may be carried
out simply from an initial temperature of 20.degree. C. to an
ultimate temperature of 85.degree. C. In the method referred to
above, however, the formation of air bubbles cannot be avoided
unless the heating is performed from an initial temperature of
35.degree. C. to an ultimate temperature of 95.degree. C. so that
even if the depth (height), width, and pitch of troughs or ridges
are optimized, the embossments must be collapsed to a certain
volume. Consequently, the initial temperature and the ultimate
temperature must be shifted upward almost in parallel, with the
result that the effect of increasing the productivity of
preliminary contact bonding, which is a deaeration process, is
small.
SUMMARY OF INVENTION
[0034] In the above state of the art, the present invention has for
its object to provide an interlayer for a laminated glass which
does not give rise to the moir phenomenon even when the arrangement
and pitch of its embossments are orderly, hence providing for good
workability in cutting and laminating operations and good
deaeration in preliminary contact bonding, thus insuring the
production of a laminated glass of high quality with a minimum of
rejects for reasons of air bubbles, and a laminated glass
containing said interlayer.
[0035] The invention has for its further object to provide an
interlayer for a laminated glass which provides for good deaeration
without a risk for premature marginal sealing even if the
temperature at initiation of deaeration at preliminary contact
bonding is not critically controlled and which does not require
raising of temperature for achieving a marginal seal of the
glass-interlayer assembly, and a laminated glass containing said
interlayer.
[0036] The present invention has for its still further object to
provide an interlayer for a laminated glass which is satisfactory
in the resistance to blocking during storage, handling workability
and productivity in the processing of glass, as well as deaeration
and sealing properties at preliminary contact bonding and which is
capable of adapting itself with ease and efficiently to varied
processing needs of various users, and a laminated glass containing
said interlayer.
[0037] The present invention is directed to an interlayer for a
laminated glass which comprises a thermoplastic resin sheet
provided with embossments comprising concave portions and convex
portions on both sides thereof (hereinafter referred to sometimes
as "interlayer").
[0038] The first aspect of the present invention is concerned with
an interlayer for a laminated glass in which a pitch of embossments
on one side is different from a pitch of embossments on the other
side.
[0039] In accordance with the first aspect of the invention, it is
preferable that concave portions on at least one side are continual
and it is more preferable that bottoms of concave portions on at
least one side are continual.
[0040] In this first aspect of the invention, it is preferable that
the pitch (L1) of embossments on one side and the pitch (L2) of
embossments on the other side satisfy the relation of (L1)<(L2),
and the proportion of existence of a convex portion on the other
side within the range (L1.times.0.25) of before and after a
position of a convex portion on one side is not more than 50% of
the number of convex portions on one side.
[0041] In the first aspect of the invention, it is further
preferable that concave portions on at least one side are provided
in a linear pattern.
[0042] The second aspect of the present invention is an interlayer
for a laminated glass in which said concave portions on at least
one side have a trough-like geometry with a continual bottom while
said convex portion on the same side has a plateau-forming top.
[0043] In the second aspect of the present invention, it is
preferable that fine concave and convex portions are provided on
the plateau-forming top surface of the convex portion.
[0044] In the second aspect of the invention, a surface roughness
Ra of the plateau-forming top surface is preferably not less than
2.5 .mu.m, more preferably not less than 3.0 .mu.m.
[0045] In the second aspect of the invention, a width of the
plateau-forming top surface is preferably not less than 20% of a
pitch of convex portions.
[0046] In the second aspect of the invention, the width of the
plateau-forming top surface may be constant or random.
[0047] The third aspect of the present invention is concerned with
an interlayer for a laminated glass in which said concave portions
on at least one side have a trough-like geometry, and segmenting
walls are formed within said trough-like geometry.
[0048] In the third aspect of the invention, a height of the
segmenting wall is preferably smaller than a depth of the
trough.
[0049] In the third aspect of the invention, the segmenting walls
are preferably arranged at equal intervals.
[0050] The fourth aspect of the present invention is an interlayer
for a laminated glass in which said concave portions on at least
one side have a trough-like geometry and are not on one and the
same level, and a ratio of a surface roughness (Rz) and a surface
roughness (Rzv) of a negative model is Rzv/Rz.gtoreq.0.25 on at
least one side.
[0051] In the fourth aspect of the invention, troughs may be
provided in a linear configuration or a grid configuration.
[0052] The fifth aspect of the present invention is concerned with
an interlayer for a laminated glass in which said concave portions
on at least one side have a continual trough-like geometry, and
said convex portion on the same side has segmenting troughs while a
bottom of said segmenting trough is not on one and the same level
as a bottom of the continual trough-like geometry of said concave
portion.
[0053] In the firth aspect of the invention, the trough-like
geometry of the concave portion and segmenting troughs of said
convex portion may be provided in a grid configuration or a in
random configuration.
[0054] In the fifth aspect of the invention, a depth of segmenting
troughs of the convex portion may be uniform or random.
[0055] The sixth aspect of the present invention is concerned with
an interlayer for a laminated glass in which at least one side is
provided with concave troughs, and an angle between said concave
trough and a direction of extrusion of said thermoplastic resin
sheet is less than 25.degree..
[0056] The seventh aspect of the present invention is concerned
with an interlayer for a laminated glass in which said concave
portions on at least one side have a trough-like geometry, and said
trough-like geometry is constant in sectional area while has a
depth distribution of troughs having a depth of not less than 5% of
the maximum trough depth.
[0057] In the seventh aspect of the invention, troughs having the
depth of not less than 5% of the maximum trough depth are
preferably provided at a pitch of not more than 10 mm.
[0058] In the seventh aspect of the invention, the trough-like
geometry is preferably provided in parallel with the direction of
flow of the interlayer for a laminated glass.
[0059] In the present invention, the thermoplastic resin sheet is
preferably a plasticized polyvinyl acetal resin sheet.
[0060] A laminated glass obtainable by interposing the interlayer
for a laminated glass according to the invention between at least
one pair of glass sheets and consolidating them into an integral
unit also constitutes one aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0061] FIG. 1 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Examples 1 to 3.
[0062] FIG. 2 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Comparative Example 1.
[0063] FIG. 3 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Example 4.
[0064] FIG. 4 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Example 5.
[0065] FIG. 5 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Example 6.
[0066] FIG. 6 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Comparative Example 2.
[0067] FIG. 7 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 8 and 9.
[0068] FIG. 8 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 10 and 11.
[0069] FIG. 9 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayer for a
laminated glass which is obtained in Comparative Example 3.
[0070] FIG. 10 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 12 and 13.
[0071] FIG. 11 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 14 and 15.
[0072] FIG. 12 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayer for a
laminated glass which is obtained in Example 16.
[0073] FIG. 13 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayer for a
laminated glass which is obtained in Comparative Example 4.
[0074] Referring to FIG. 7 to FIG. 13, a represents the pitch of
convex portions, b represents the width of the plateau-forming top
surface of the convex portion, and c represents the width of the
concave portion.
[0075] FIG. 14 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 17 and 18.
[0076] FIG. 15 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 19 and 20.
[0077] FIG. 16 is a schematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayer for a
laminated glass which is obtained in Comparative Example 5.
[0078] FIG. 17 is a perspective view showing a wedge-shaped tracer
(tip width 1000 .mu.m, opposite face angle 90.degree.) for use in
Rzv measurement.
[0079] FIG. 18 is a perspective view showing the embossment pattern
of the interlayer for a laminated glass according to the fifth
aspect of the invention.
[0080] FIG. 19 is a plan view showing the embossment pattern of the
interlayer for a laminated glass according to the fifth aspect of
the invention.
[0081] Referring to FIG. 18 and FIG. 19, 1 represents the
trough-like configuration of the concave portion, 2 represents the
segmenting troughs of the convex portion, and 3 represents the
depth of segmenting troughs of the convex portion.
[0082] FIG. 20 shows an interlayer for a laminated glass according
to the sixth aspect of the invention, where (a) is a plan view and
(b) is a side elevation view.
[0083] Referring to FIG. 20, 4 represents a concave trough and 5
represents an embossment.
DETAILED DESCRIPTION OF THE INVENTION
[0084] The present invention is now described in detail.
[0085] The interlayer of the invention comprises a thermoplastic
resin sheet.
[0086] As the thermoplastic resin sheet to be used in the
invention, any of the known sheets available for use as laminated
glass interlayers can be utilized; thus, for example, plasticized
polyvinyl acetal resin sheet, polyurethane resin sheet,
ethylene-vinyl acetate resin sheet, ethylene-ethyl acrylate resin
sheet, and plasticized vinyl chloride resin sheet can be mentioned.
While these thermoplastic resin sheets are quite satisfactory in
the basic properties required of a laminated glass interlayer, such
as adhesion, weather resistance, bullet resistance, transparency,
etc., the plasticized polyvinyl acetal resin sheet represented by
plasticized polyvinyl butyral resin sheet can be used with
particular advantage.
[0087] The plasticized polyvinyl acetal resin mentioned above is
preferably a resin composition predominantly composed of polyvinyl
acetal resin and as the polyvinyl acetal resin, a polyvinyl butyral
resin having a butyralization degree of 60 to 70 mol % and a
polymerization degree of 1000 to 2000, for instance, can be used
with advantage.
[0088] The plasticizer which can be used for said plasticized
polyvinyl acetal resin sheet includes ethylene glycol di-2-ethyl
butyrate, 1,3-propylene glycol di-2-ethylbutyrate, 1,4-propylene
glycol di-2-ethylbutyrate, 1,4-butylene glycol di-2-ethylbutyrate,
1,2-butylene glycol di-2-ethylbutyrate, diethylene glycol
di-2-ethylbutyrate, diethylene glycol di-2-ethylhexoate,
dipropylene glycol di-2-ethylbutyrate, triethylene gycol
di-2-ethylpentoate, triethylene glycol di-2-ethylhexoate,
tetraethylene glycol di-2-ethylbutyrate, diethylene glycol
dicaprylate, and triethylene glycol dicaprylate.
[0089] In the present invention, the addition level of such
plasticizer is preferably within the range of 20 to 60 parts by
weight per 100 parts by weight of polyvinyl acetal resin.
[0090] Furthermore, where necessary, the interlayer according to
the invention may contain various additives such as heat
stabilizer, ultraviolet absorber, adhesion modulating agent, and so
forth.
[0091] The thickness of said thermoplastic resin sheet can be
selected accordingly in consideration of the bullet resistance and
other properties required of laminated glass and is not
particularly restricted but, just as it is the case with the
conventional interlayer, the preferred thickness is 0.2 to 2
mm.
[0092] For use as the interlayer according to the invention, said
thermoplastic resin sheet is provided with embossments comprising
concave portions and convex portions on both sides.
[0093] Unless the parameters specific to the respective aspects of
the invention are dissatisfied, the above embossment pattern is not
particularly restricted but encompasses a variety of concave and
convex patterns having multiplicities of convex portions and
complementary concave portions. The distribution of such convex and
concave patterns may be orderly or random, although an orderly
distribution is preferred.
[0094] The above convex portions may be equal or varying in height
and the corresponding concave portions may also be equal or varying
in depth.
[0095] Unless the parameters specific to the respective aspects of
the invention are dissatisfied, the geometry of the above convex
portion is not particularly restricted but includes various cones
inclusive of triangular pyramid, quadrangular pyramid, circular
cone, etc.; truncated cones such as truncated triangular pyramid,
truncated quadrangular pyramid, truncated circular cone, etc.; and
pseudocones having a hill or hemispherical head. The geometry of
the above concave portion is complementary to that of said convex
portion.
[0096] The technology of forming the embossment includes the
embossing roll method, calender roll method, contour extrusion
method, and extrusion-lip embossing method which takes advantage of
melt fracture, among others. Particularly preferred among them is
the embossing roll method by which an embossment quantitatively
comprising constant and fine concave and convex portions can be
produced.
[0097] The embossing roll for use in the above embossing roll
method includes the one manufactured by subjecting the surface of a
metal roll to blasting with grits of aluminum oxide, silicon oxide
or the like and, then, to lapping with a vertical grinder or the
like to reduce excessive surface peaks to thereby form a fine
embossment pattern (concave and convex patterns) on the roll
surface, the one obtained by using an engraving mill (mother mill)
and transferring the embossment pattern (concave and convex
patterns) of this engraving mill to the surface of a metal roll to
produce a fine embossment pattern (concave and convex patterns) on
the roll surface, and the one obtained by forming a fine embossing
pattern (concave and convex patterns) on the surface of a roll by
etching, among other methods.
[0098] Referring to the geometry of said embossment, the ease of
release of air in deaeration at the preliminary contact bonding
between the glass sheet and the interlayer is related to the
continuity of the concave portions of the concavo-convex
configuration, and the pitch and arrangement of concave portions
have no important bearing on the ease of escape of air. In the
early phase of deaeration, the air in the concave portion of the
concavo-convex configuration flows from the interface with the
glass selectively into the trough comprised of the concave
portions. Then, the air in the trough is forced out via the trough
and the amount of air that remains in the trough is of the order
which the interlayer can sufficiently absorb.
[0099] The dimensions of the above convex portion and of the above
concave portion are not particularly restricted unless the
parameters specific to the respective aspects of the invention are
dissatisfied but the interval (pitch) of convex portions is
preferably 10 .mu.m to 1 cm, more preferably 50 to 1000 .mu.m,
particularly preferably 200 to 800 .mu.m. Within the range of 200
to 800 .mu.m, a still greater improvement in clarity is obtained.
The height of the convex portion is preferably 5 to 500 .mu.m, more
preferably 20 to 100 .mu.m. Furthermore, the length of the bottom
of each convex portion is preferably 30 to 1000 .mu.m. It should be
understood that the term "pitch" as used in this specification
means the distance from the center of a convex or concave portion
to the center of the adjacent convex or concave portion.
[0100] The collapsibility of the embossment at preliminary contact
bonding is largely dependent on the volume of the embossment. The
determinants of the volume of embossments are the pitch and
arrangement of convex portions and the expanse of the
plateau-forming top of the convex portion. The larger the
plateau-forming top of the convex portion is, the larger is the
volume of embossments that can be established and, hence, the
degree of coarseness of embossing can be smaller. When a large
embossment volume can be set, there can be obtained an interlayer
for a laminated glass which is free from the problem of premature
sealing. At the temperature necessary for marginal sealing at
preliminary contact bonding, the interlayer for a laminated glass
becomes sufficiently fluid so that insofar as the coarseness of
embossment is within a given range, the margin can be sufficiently
sealed.
[0101] The first aspect of the present invention is concerned with
an interlayer for a laminated glass in which a pitch of embossments
on one side is different from a pitch of embossments on the other
side.
[0102] By embossing in such manner that the pitch of embossments on
one side of the interlayer is different from the pitch of
embossments on the other side in accordance with the first aspect
of the invention, appearance of said moir phenomenon can be
effectively inhibited even if the arrangement and pitch of
embossments are comparatively orderly.
[0103] Generally speaking, appearance of the moir phenomenon is
liable to occur when the embossments on the both sides of an
interlayer are nearly identical in arrangement and pitch.
Therefore, by embossing in such manner that the pitch of embossment
is different from the pitch on the other side, that is to say by
creating a difference between the pitch of embossments on one side
and the pitch of embossments on the other side intentionally, it
becomes possible to effectively inhibit appearance of the moir
phenomenon even when the arrangement and pitch of embosses on each
side are comparatively orderly.
[0104] In the first aspect of the invention, it is preferable that
the concave portions on at least one side are continual.
[0105] By insuring that the concave portions of the embossment on
at least one side of an interlayer is continual, the concave
portions of the embossment become intercommunicable so that the
efficiency of deaeration in preliminary contact bonding is
remarkably improved and, hence, the resulting laminated glass will
be of high quality with a minimized incidence of rejects for
reasons of inclusion of air bubbles. Furthermore, it is more
preferable that the bottoms of the concave portion on at least one
side of the interlayer are continual.
[0106] In the first aspect of the invention, the pitch of
embossments on one side of the interlayer is preferably not less
than 1.25 times the pitch of embossments on the other side. If the
pitch of embossments on one side is smaller than 1.25 times the
pitch of embossments on the other side, the inhibitory effect on
appearance of the moir phenomenon tends to be insufficient. The
more preferred ratio is not less than 1.3 times.
[0107] Furthermore, in the first aspect of the invention, it is
preferable that the pitch (L1) of embossments on one side and the
pitch (L2) of embossments on the other side satisfy the relation of
(L1)<(L2), and the proportion of existence of a convex portion
on the other side within the range (L1.times.0.25) of before and
after a position of a convex portion on one side is not more than
50% of the number of convex portions on one side. When the convex
portions satisfy the topological conditions defined above, the
concave portions also satisfy the above topological conditions.
Thus, the proportion of existence of a concave portion on the other
side within the range (L1.times.0.25) of before and after the
position of a concave portion on one side is preferably not more
than 50% of the number of concave portions on one side. As used in
this specification, the term "position of a convex portion or a
concave portion" means the position of the center of the convex or
concave portion and the term "existence of a convex portion or a
concave portion" means the existence of the center of a convex or
concave portion. When the embossment on one side and the embossment
on the other side are arranged to satisfy the above requirement,
appearance of the moir phenomenon can be effectively inhibited. The
more preferred proportion is not more than 30%, the still more
preferred proportion is not more than 10%, and the particularly
preferred proportion is 0%, that is the case where, within the
range (L1.times.0.25) of before and after the position of a convex
or concave portion on one side, there exists not a single convex
portion or concave portion, as the case may be, on the other
side.
[0108] Furthermore, in the first aspect of the present invention,
it is preferable that the concave portions on at least one side are
provided in a linear pattern.
[0109] While the emboss pattern of depressions is not limited to a
linear one but may for example be a grid pattern, a radiant
pattern, or a hemispherical pattern, a further improvement in the
deaeration efficiency at preliminary contact bonding can be
realized by adopting a linear pattern for concave portions on at
least one side of the interlayer.
[0110] In the first aspect of the invention, it is so arranged that
the pitch of embossments on one side is different from the pitch of
embossments on the other side. As this difference is intentionally
created between the pitch of embossments on one side and the pitch
of embosses pattern on the other side, the moir phenomenon does not
take place even when the arrangement and pitch of embosses are
orderly, so that the workability in cutting and laminating
operations are improved.
[0111] Furthermore, when the embossment is such that the concave
portions on at least one side are continual, the concave portions
of the embossment are intercommunicable so that the deaeration
efficiency at preliminary contact bonding in laminated glass
processing is improved. Therefore, the resulting laminated glass is
of high quality with a minimized incidence of rejects for reasons
of inclusion of air bubbles.
[0112] In addition, by carrying out embossing in such manner that
the pitch of the embossments on one side will be not smaller than
1.25 times the pitch of the embossments on the other side or the
proportion of existence of a convex portion on the other side
within the range (L1.times.0.25) of before and after the position
of a convex portion on one side will be not more than 50% of the
number of convex portions on one side, the inhibitory effect on the
moir phenomenon is still further improved.
[0113] Furthermore, by embossing in such a manner that the pattern
of concave portions on at least one side will be a linear pattern,
the deaeration efficiency-improving effect is further enhanced.
[0114] The second aspect of the invention is concerned with an
interlayer for a laminated glass in which the concave portion on at
least one side has a trough-like geometry with a continual bottom
while the convex portion on the same side has a plateau-forming
top.
[0115] In the second aspect of the invention in which the concave
portion on at least one side has a trough-like geometry with a
continual bottom, a marked improvement in deaeration efficiency can
be realized.
[0116] Furthermore, in this second aspect of the invention, the
projecting top of the convex portion is flattened. The larger the
area of the plateau-forming top is, the larger is the volume of
convex portions of the embossment, with the result that the average
surface roughness of the emboss can be relatively reduced and,
hence, said premature marginal sealing of the glass-interlayer
assembly in the preliminary contact bonding stage can be
effectively prevented. Moreover, the interlayer will be
sufficiently fluid at the ordinary temperature which is necessary
for effecting a marginal seal of the glass-interlayer assembly in
the preliminary contact bonding stage and, therefore, to effect a
sufficient marginal seal at such an ordinary temperature, the
average surface roughness of the embossment is preferably not
greater than 100 .mu.m, more preferably not greater than 70
.mu.m.
[0117] Since, in the second aspect of the invention, the concave
portion on at least one side has a trough-like geometry with a
continual bottom while the convex portion on the same side has the
plateau-forming top, the section perpendicular to the direction of
extension of the convex portion has a trapezoid configuration with
an increased top area of the convex portion and the consequently
increased volume of the convex portion so that the premature
marginal sealing of the glass-interlayer assembly is effectively
precluded in the preliminary contact bonding stage. Therefore, the
air present in the central area of the glass-interlayer assembly
can be effectively removed in the preliminary contact bonding
stage.
[0118] The above-mentioned convex portion preferably has fine
concave and convex portions on the plateau-forming top surface.
Flattening the top of the convex portion may result in an increased
self-adhesion of the interlayer but this self-adhesion can be
suppressed for improved handleability by forming such fine concave
and convex portions on said plateau.
[0119] The surface roughness of said top surface is preferably not
less than Ra=2.5 .mu.m. When Ra is not less than 2.5 .mu.m, the
sheet-to-sheet contact area of the interlayer is so small that even
when the interlayer is stored as a stack in the conventional
manner, self-adhesion will not be a matter of concern. More
preferably, Ra is not less than 3.0 .mu.m.
[0120] FIG. 7 is a schematic diagram showing the emboss pattern
(concave and convex patterns) of the interlayers obtained in
Example 8 and Example 9 which are described hereinafter. In FIG. 7,
a represents the interval (pitch) of convex portions of the
embossment and b represents the width of the plateau-forming top of
the convex portion of the embossment.
[0121] In the second aspect of the invention, said width (b) of the
plateau is preferably not less than 20% of the pitch of convex
portions, i.e. b/a is preferably not less than 20%. If b/a is less
than 20%, there may not be obtained a sufficient increase in said
volume of convex portions so that said premature marginal sealing
may not be well inhibited. On the other hand, if b/a is as great as
100%, there will exist substantially no concave portion of the
embossment. Therefore, b/a is preferably less than 100%, more
preferably not more than 90%.
[0122] Moreover, in the second aspect of the invention, the width
of said plateau may all be constant or may vary locally, i.e. may
be of random width.
[0123] In the second aspect of the invention, it is preferable that
the pitch of concave and convex patterns on one side is different
from the pitch of concave and convex patterns on the other side. If
these are equal, the moir phenomenon tends to take place.
[0124] The embossment pattern (concave and convex patterns) in the
second aspect of the invention is not particularly restricted but
includes linear, grid-like, radial and hemispherical, among
others.
[0125] Since, in the second aspect of the invention, said concave
portions on at least one side of the interlayer form a trough-like
geometry which is continual at the bottom, the bottom of said
concave portions is continual so that good deaeration can be
achieved in preliminary contact bonding.
[0126] In addition, since the top of said convex portion forms a
plateau, the area of the top of said convex portion and the volume
of said convex portion are increased so that the premature marginal
sealing of the glass-interlayer assembly in preliminary contact
bonding is effectively inhibited. Therefore, the air present in the
central part of the glass-interlayer assembly is also effectively
purged out. In particular, the above characteristics are further
improved when the ratio of the width of said plateau at top of said
convex portion relative to the pitch of said convex portions is not
less than 20%.
[0127] The third aspect of the invention is concerned with an
interlayer for a laminated glass in which said concave portion on
at least one side has a trough-like geometry and segmenting walls
are formed in said trough-like geometry.
[0128] In the third aspect of the invention, said trough has
segmenting walls therein. In this arrangement, even if a positive
seal cannot be carried out down to the bottom of the trough, the
segmenting walls lying above the level of the bottom of necessity
help to insure a positive seal between the interlayer and the glass
sheet, thus allowing milder sealing conditions to be employed.
[0129] The height of the above segmenting wall is preferably
smaller than the depth of the trough. If the height of the
segmenting wall is greater than the depth of the trough, there may
be cases in which deaeration and sealing will be insufficient.
[0130] The above segmenting walls are preferably arranged at equal
intervals. If the interval of the above segmenting walls is not
uniform, it may happen that deaeration does not proceed with
efficiency.
[0131] In the third aspect of the invention, the pitch of the
concave and convex patterns on one side is preferably different
from the pitch of the concave and convex patterns on the other
side. If the pitches are similar, the moir phenomenon is liable to
take place.
[0132] The fourth aspect of the invention is concerned with an
interlayer for a laminated glass in which said concave portion on
at least one side has a trough-like geometry and is not on one and
the same level, and a ratio of a surface roughness (Rz) and a
surface roughness (Rzv) of a negative model is Rzv/Rz.gtoreq.0.25
on at least one side.
[0133] Rz, referred to above, represents the surface roughness of
the embossments on at least one side and it is a 10-point average
roughness as measured with a conical tracer (tip radius of
curvature 5 .mu.m, vertex angle 90.degree.) in accordance with JIS
B 0601. Rzv, referred to above, represents the surface roughness of
the negative model used for the embossment on at least one side and
it is a 10-point average roughness as measured with a wedge-shaped
tracer shown in FIG. 17 (tip width 1000 .mu.m, opposite face angle
90.degree.) shifted in a direction normal to the tip width in
accordance with JIS B 0601.
[0134] As used in this specification, the term "not on one and the
same level" means that the trough is not uniform in depth.
[0135] Rz, referred to above, represents the well-known ordinary
10-point average roughness and is generally measured with a digital
tracer-type electric surface roughness analyzer.
[0136] Rzv, referred to above, is also generally measured with a
digital tracer-type electric surface roughness analyzer.
[0137] Stated differently, said Rzv is the 10-point average
roughness as measured with a wedge-shaped tracer (tip width 1000
.mu.m) assuming that the convex portion of the embossment on the
sheet surface is a concave portion and the concave portion of the
embossment is a convex portion. Here, the tip width of the
wedge-shaped tracer is set to 1000 .mu.m in consideration of the
pitch of the convex portion and concave portion of the embossment
(which is usually 200 to 1000 .mu.m). By using a tracer having a
tip width of 1000 .mu.m, the change in geometry of particularly
deep concave portions among the concave portions of the embossments
can be measured.
[0138] The above-mentioned Rzv serves also as a parameter
representing the level of the concave portion of the embossment and
is closely related to the ease of escape of air in deaeration and
the sealing effect. On the other hand, said Rz serves also as a
parameter representing the condition of the convex portion of the
embossment and is not only related to the resistance to movement of
air but is closely related to the ease of collapse of the
embossment in laminating work.
[0139] Intensive analysis of the relationship of the above Rzv to
Rz revealed that when the relation of Rzv/Rz.gtoreq.0.25 is
satisfied, the deaeration and sealing performances in preliminary
contact bonding are satisfactory and, in the final contact bonding
carried out under heat and pressure in an autoclave, there is
obtained an interlayer almost free of the air bubbles which might
be formed between the glass and interlayer due to infiltration of
pressurized air from the poorly sealed positions.
[0140] Blocking of the interlayer depends on the number of the
interlayer stacked during storage but generally an interlayer
having a 10-point average roughness (Rz) value of 20 to 100 .mu.m
is employed and for such an interlayer, it is only necessary to
take into consideration a gravity of the order of about 500 to 1000
sheets. It has been found that the interlayer satisfying the
above-defined conditions shows satisfactory blocking resistance
under a load of such magnitude and can be easily handled in storage
and laminating work.
[0141] In the fourth aspect of the invention, the preferred
interlayer is one having a defined surface roughness on both sides
thereof but an interlayer having a defined surface roughness only
on one side with the other side having the conventional embossment
comprising fine concave and convex patterns is also acceptable.
[0142] In the fourth aspect of the invention, the trough may be
provided in a linear configuration or in a grid configuration.
[0143] The fifth aspect of the invention is an interlayer for a
laminated glass in which the concave portion on at least one side
has a continual trough-like geometry and said convex portion on the
same side has segmenting troughs while a bottom of said segmenting
troughs is not on one and the same level as the bottom of the
continual trough-like geometry of said concave portion.
[0144] The main function of the segmenting troughs of the convex
portion is to control the magnitude of the concave and convex.
Thus, when the number of said segmenting troughs is increased, the
volume of the concave and convex is decreased to facilitate sealing
particularly at the marginal part of the glass-interlayer assembly
and conversely when the number of said segmenting troughs is
decreased, the volume of surface irregularities is increased so
that the premature marginal sealing and consequent entrapment of
air in the central region of the glass-interlayer assembly can be
effectively precluded.
[0145] The geometry of said segmenting trough in the convex portion
can be freely controlled so that an interlayer having both a good
deaeration characteristic due to the continual trough-like geometry
of the concave portion and the good sealing characteristic due to
the above segmenting troughs of the convex portion can be provided
easily and efficiently in response to varied processing needs of
various users.
[0146] FIG. 18 is a perspective view showing the emboss design of
an interlayer for a laminated glass according to the fifth aspect
of the invention and FIG. 19 is a plan view of the same.
[0147] In the fifth aspect of the invention, the trough-like
geometry 1 of the concave portion and segmenting troughs 2 of the
convex portion may be provided in a grid or a random configuration
but the grid configuration is preferred.
[0148] Further in the fifth aspect of the invention, the depth of
segmenting troughs 3 in the convex portion may be uniform or
random, although a uniform depth is preferred.
[0149] In the fifth aspect of the invention, both sides of the
interlayer preferably have an embossment satisfying the
herein-defined conditions but an interlayer having an embossment
satisfying defined conditions only on one side with the other side
having the conventional embossment is also acceptable.
[0150] In the fifth aspect of the invention, the concave portions
on at least one side have a continual trough-like geometry and even
when the geometry of the embossment is destroyed under heat and
pressure in the preliminary contact bonding of the glass-interlayer
assembly, the continual trough-like geometry of the concave portion
persists to the last. Therefore, sufficient deaeration can be
achieved.
[0151] Furthermore, in the fifth aspect of the invention, the
convex portion complementary to the concave portion has segmenting
walls and, moreover, the bottom of the segmenting trough is not on
one and the same level as the bottom of the continual trough-like
geometry of the concave portion, the sealing performance in
laminated glass processing can be improved by controlling the
geometry of the segmenting trough of the convex portion.
Furthermore, through such control of the geometry of the segmenting
trough of the convex portion, the different processing needs of
various users can be met with ease and efficiency.
[0152] The sixth aspect of the invention is concerned with an
interlayer for a laminated glass in which at least one side is
provided with concave troughs, and an angle between said concave
trough and a direction of extrusion of the thermoplastic resin
sheet is less than 25.degree..
[0153] If this angle between the concave trough provided on the
thermoplastic resin sheet used in sixth aspect of the invention and
the extrusion direction of the thermoplastic sheet is too large,
bubbling (formation of air bubbles) tends to occur in the laminated
glass particularly when the preliminary contact bonding is
performed by the draw deaeration method and, moreover, if the
concave trough extends to the edge of the sheet, a sealing defect
occurs to entrap air in the final contact bonding which is carried
out under heat and pressure in an autoclave. Therefore, said angle
is restricted to less than 25.degree., preferably less than
15.degree..
[0154] The concave trough mentioned above is a continual trough and
when a plurality of troughs are present, they are preferably
identical in depth, width and pitch, although there may be a
moderate undulation at the bottom of the trough or they may be
randomly present, varying in depth, width, and/or pitch. The
sectional configuration of the concave trough is not particularly
restricted but each trough may for example be V-shaped, U-shaped,
or bracket-shaped.
[0155] Regarding the depth of the above concave trough, if the
trough is too shallow, the deaeration performance will be decreased
and if it is too deep, a sealing defect may develop. Therefore, the
depth of the trough is preferably 5 to 500 .mu.m, more preferably
20 to 70 .mu.m. The width of the trough is preferably 20 to 100
.mu.m, for if it is too narrow, the deaeration performance will be
poor and if it is too broad, a sealing defect tends to develop. The
interval (pitch) of concave troughs is preferably 0.1 to 10 mm,
more preferably 0.2 to 1 mm, for if the interval is too small, the
deaeration performance will be poor and if it is too large, a
sealing defect tends to develop.
[0156] In the sixth aspect of the invention, concave troughs need
only be formed on at least one side of a thermoplastic resin sheet.
Thus, it is optional to provide the interlayer with troughs on one
side or on both sides but in order that a sufficient deaeration
effect may be obtained, troughs are preferably formed on both
sides.
[0157] In the sixth aspect of the invention, the thermoplastic
resin sheet is formed not only with concave troughs but also with a
multiplicity of fine depressions and convex portions as embossed on
both sides. The distribution of these fine concave and convex may
be orderly or not orderly. Moreover, the depth and height of
concave and convex may each be uniform throughout or varying.
[0158] In the sixth aspect of the invention which has the above
constitution, concave troughs persist even after the concave and
convex of the embossment are abolished by heat and pressure in
preliminary contact bonding, particularly in the draw deaeration
process in processing laminated glass. Therefore, sufficient
deaeration can be insured.
[0159] When the draw deaeration method is used in preliminary
contact bonding, the ease of escape of air in this preliminary
contact bonding stage is closely and substantially exclusively
related to the proportion of concave troughs relative to the total
depression portion and the flatness and smoothness of the concave
troughs, with the pitch and arrangement of convex portions being
not so influential factors.
[0160] In the sixth aspect of the invention, by virtue of the
formation of concave troughs in parallel with the extrusion
direction, a route for air can be insured even when, for example,
the convex portion is in the form of a mountain ridge, the
deaeration passage way is arranged in a grid form, and deaeration
is performed at right angles with the mountain ridge. Therefore,
even when the deaeration is carried out at right angles with said
mountain ridge, the air will not be dammed and, hence, no air pool
will be formed.
[0161] Furthermore, in the recent technology for laminated glass
production, it is the rule rather than exception to construct a
glass-interlayer assembly along the winding flow direction of the
interlayer (generally the extrusion direction of the thermoplastic
resin sheet) and carrying out a draw deaeration along the winding
flow direction. Therefore, the marginal sealability of the
interlayer in preliminary contact bonding is improved when concave
troughs are oriented along the winding flow direction of the
interlayer.
[0162] Furthermore, when a glass-interlayer assembly is subjected
to preliminary contact bonding, many processing manufactures
generally set the initial speed at insertion of the assembly into
the multi roll system and the speed immediately before takeoff at
definitely slower levels compared with the normal speed for the
purpose of preventing cracking of glass due to curving, with the
result that the leading end and trailing end of the laminate can be
sufficiently sealed even if the roughness of the embossment and the
size of the concave trough at these ends are large. There is no
problem with sealing at the lateral edges unless a concave trough
exists at the lateral edge of the assembly.
[0163] The seventh aspect of the invention is concerned with an
interlayer for a laminated glass in which concave portion on at
least one side has a trough-like geometry, and said trough-like
geometry is constant in sectional area while has a depth
distribution of troughs having a depth of not less than 5% of the
maximum trough depth.
[0164] In the seventh aspect of the invention, the concave portion
on at least one side has the trough-like geometry and, with the
depth of the trough being reduced locally, has a depth distribution
of troughs having a depth of not less than 5% of the maximum trough
depth, while the sectional area of the trough-like geometry is kept
constant. Therefore, in the deaeration by the vacuum deaeration
technique, an effective route for air is insured at initiation of
deaeration and the shallow parts become more ready to adhere to the
glass so that the sealability is improved.
[0165] Troughs having a depth distribution of not less than 5% of
the maximum trough depth as mentioned above are preferably provided
at an interval (pitch) of not more than 10 mm. If this pitch
exceeds 10 mm, the trouble of bubble formation in the marginal part
of the glass-interlayer assembly may occur in the course of
deaeration. The more preferred pitch is not more than 2 mm.
[0166] In the seventh aspect of the invention, the trough-like
geometry is preferably provided in the direction of flow of the
interlayer. As used in this specification, the "flow direction"
means the direction of travel of the glass-interlayer assembly on a
laminated glass production line. In this arrangement, not only the
molding of the roll to be used for transfer of the trough-like
geometry to the interlayer but also the transfer to the substrate
interlayer sheet is facilitated. In addition, this arrangement is
preferred in view of the fact that the direction of deaeration in
the draw deaeration technique is the flow direction of the
interlayer.
[0167] The above trough-like geometry need only be formed on one
side of the interlayer in accordance with the seventh aspect of the
invention but is preferably present on both sides. When the
trough-like geometry is present on at least one side of the
interlayer of the invention, the formation of air bubbles can be
prevented by using the interlayer of the invention when, for
example, the inner side of the glass has a distribution of
roughness or the interlayer is to be used only on the side for
absorbing the steps due to black ceramics printing or the like.
[0168] The interlayer according to the seventh aspect of the
invention can be used with advantage when the deaeration is
performed by the vacuum deaeration technique but by increasing the
fineness of the trough, for example by reducing the depth of the
trough to less than about 30 .mu.m, it can be used with success
when the deaeration is performed by the draw deaeration technique
as well.
[0169] The technology of creating said trough-like geometry
includes, for example, the method which comprises processing the
surface of a metal roll or a flat plate (pressed plate) into a
convex (ridge-like) form and transfer the form to a substrate
interlayer.
[0170] Referring, further, to the above trough-like geometry, the
depth of the trough can be varied with its sectional area kept
constant by indenting the surface ridge of a metal roll or flat
plate (pressed plate) locally and particularly the method which
comprises biasing a mill having a defined geometry against said
surface to vary the depth of the trough is preferred in that the
sectional area of the trough can be easily kept constant. In
contrast, if the surface ridge of a metal roll or flat plate
(pressed plate) is machined with a bit or the like to reduce its
height, the sectional area of that portion will be decreased.
[0171] The interlayer according to the present invention is used
for the manufacture of laminated glass products. Such a laminated
glass can be obtained by interposing the interlayer of the
invention between at least one pair of glass sheets and
consolidating the assembly into an integral unit.
[0172] The glass sheet mentioned above is not particularly
restricted but includes inorganic glass sheets; and organic glass
sheets such as the polycarbonate sheet, polymethyl methacrylate
sheet, and so forth.
[0173] The structure of said laminated glass need only be such that
the interlayer of the invention is interposed between two glass
sheets and is otherwise not particularly restricted. Thus, the
structure is not restricted to the 3-layer structure of sheet
glass/interlayer/sheet glass but may be a multilayer structure of,
for example, sheet glass/interlayer/sheet glass/interlayer/sheet
glass.
[0174] The technology of manufacturing a laminated glass product
using the interlayer of the invention is not particularly
restricted. Thus, the desired laminated glass can be obtained by
the same production technology as used in the manufacture of the
conventional laminated glass, for example by interposing the
interlayer between at least one pair of glass sheets, subjecting
the whole to preliminary contact bonding for deaeration and
provisional adhesion, and subjecting it to final contact bonding,
for example, in an autoclave.
[0175] When the laminated glass is to be manufactured using the
interlayer made of, for example, a plasticized polyvinyl butyral
resin sheet in accordance with the invention, the preliminary
contact bonding and final contact bonding can for example be
carried out in accordance with the following procedures.
[0176] The preliminary contact bonding procedure may comprise
interposing the interlayer between two transparent inorganic glass
sheets and passing the assembly over a nip roll for preliminary
contact bonding with concurrent deaeration for example at a
pressure of 2 to 1000 kPa and a temperature of 50 to 100.degree. C.
(draw deaeration technique) or accommodating said assembly in a
rubber bag, connecting the bag to a vacuum system, and evacuating
the bag to a vacuum of -40 to -75 kPa (absolute pressure 36 to 1
kPa) while increasing the temperature for preliminary contact
bonding at 60 to 100.degree. C. (vacuum deaeration technique).
[0177] The assembly subjected to the preliminary contact bonding
procedure is further subjected to final contact bonding in an
autoclave in the conventional manner or by means of a press set to
a temperature of 120 to 150.degree. C. under a pressure of 200 to
1500 kPa to give the laminated glass.
[0178] The laminated glass thus manufactured also constitutes one
aspect of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0179] The following examples illustrate the present invention in
further detail without defining the scope of the invention.
EXAMPLE 1
[0180] To 100 parts by weight of polyvinyl butyral resin (average
degree of polymerization 1700, residual acetyl group 1 mol %,
butyralization degree 65 mol %) was added 40 parts by weight of the
plasticizer triethylene glycol-di-2-ethylbutyrate, and using an
extruder, the resulting mixture was melt-kneaded and extruded in a
sheet form from the extrusion die to give a 0.76 mm-thick polyvinyl
butyral resin sheet (PVB sheet).
[0181] An engraving mill (mother mill) having a linear embossment
design (concave and convex patterns) for embossing use was forced
against the surface of one of a pair of metal embossing rolls and
this metal roll and the engraving roll were driven in association
to transfer the embossment design of the engraving mill to the
metal roll. Then, the engraving mill was shifted in the axial
direction of the metal roll in steps of the unit embossment design
to transfer the embossment design of the engraving mill to the
metal roll in the same manner as above to construct an embossing
roll having an orderly array of linear embossment designs. The
embossment pitch of the engraving mill was 250 .mu.m.
[0182] An engraving mill (mother mill) having a linear embossment
design was forced against the surface of the other metal roll of
said pair of embossing rolls and the metal roll and the engraving
mill were driven in association to transfer the embossment design
of the engraving mill to the metal roll. Then, the engraving mill
was shifted in the axial direction of the metal roll in steps of
the unit embossment design to transfer the embossment design of the
engraving mill serially to the metal roll in the same manner as the
above to construct an embossing roll with an orderly array of
linear embossment designs. The pitch of the emboss design of said
engraving mill was 320 .mu.m.
[0183] The PVB sheet (0.76 mm thick) obtained as above was passed
over the embossing roll pair obtained as above to manufacture an
interlayer sheet for laminated glass having an orderly array of
linear embossment designs on both sides but varying in the pitch of
designs from one side to the other side.
EXAMPLE 2
[0184] Except that the pitch of the embossment of one engraving
mill (mother mill) was changed to 300 .mu.m and the pitch of the
embossment of the other engraving mill (mother mill) was changed to
375 .mu.m, the procedure of Example 1 was repeated to manufacture
an interlayer for a laminated glass having an orderly array of
linear embossments on both sides and varying in the pitch of
embossments from one side to the other side.
EXAMPLE 3
[0185] Except that the pitch of the embossments of one engraving
mill (mother mill) was changed to 300 .mu.m and the pitch of the
embossments of the other engraving mill (mother mill) was changed
to 430 .mu.m, the procedure of Example 1 was repeated to
manufacture an interlayer for a laminated glass having an orderly
array of linear embossments on both sides and varying in the pitch
of embossments from one side to the other side.
[0186] The face side, reverse side, and cross-section views of the
embossment designs (concave and convex patterns) of the interlayers
for laminated glass as obtained in Examples 1 to 3 are
schematically illustrated in FIG. 1.
COMPARATIVE EXAMPLE 1
[0187] Except that the pitch of the embossments was set to 300
.mu.m for both engraving mills (mother mills), the procedure of
Example 1 was repeated to manufacture an interlayer for a laminated
glass having an orderly array of linear embossments on both sides
with the same pitch of embossments for both sides.
[0188] The face side, reverse side and cross-section views of the
embossment design (concave and convex patterns) of the interlayer
for a laminated glass as obtained in Comparative Example 1 are
schematically shown in FIG. 2.
EXAMPLE 4
[0189] To 100 parts by weight of polyvinyl butyral resin (average
degree of polymerization 1700, residual acetyl group 1 mol %,
butyralization degree 65 mol %) was added 40 parts by weight of the
plasticizer triethylene glycol-di-2-ethylbutyrate (3 GH) and, using
an extruder, the resulting mixture was melt-kneaded and extruded in
a sheet form from the extrusion die to give a 0.76 mm-thick
polyvinyl butyral resin sheet (PVB sheet).
[0190] An engraving mill (mother mill) having a hemispherical
embossment design was forced against the surface of one of a pair
of metal embossing rolls and this metal roll and the engraving mill
were driven in association to transfer the embossment design of the
engraving mill to the metal roll. Then, the engraving mill was
shifted in the axial direction of the metal roll in steps of the
unit embossment design to transfer the embossment design of the
engraving mill to the metal roll in the same manner as above to
construct an embossing roll having an orderly array of
hemispherical embossments. The pitch of the embossments of the
engraving mill was 200 .mu.m.
[0191] An engraving mill (mother mill) having a hemispherical
embossment design was forced against the surface of the other metal
roll of said pair of embossing rolls and the metal roll and the
engraving mill were driven in association to transfer the
embossment design of the engraving mill to the metal roll. Then,
the engraving mill was shifted in the axial direction of the metal
roll in steps of the unit embossment design to transfer the
embossment design of the engraving mill serially to the metal roll
to construct an embossing roll having an orderly array of
hemispherical embossments. The pitch of embossments of said
engraving mill was 300 .mu.m.
[0192] The PVB sheet (0.76 mm thick) obtained as above was passed
over the embossing roll pair obtained as above to manufacture an
interlayer for a laminated glass having an orderly array of
hemispherical embossments on both sides but varying in the pitch of
embossments from one side to the other side. The face side, reverse
side and cross-section views of the embossment pattern of the
interlayer thus obtained are shown in FIG. 3.
EXAMPLE 5
[0193] Except that a linear embossment design was used for
engraving mills (mother mills) and the pitch of embossments of one
of the engraving mills was set to 250 .mu.m and that of the other
engraving mill to 300 .mu.m, the procedure of Example 4 was
otherwise repeated to manufacture an interlayer for a laminated
glass having a linear embossment pattern on both sides and varying
in the pitch of embossments from one side to the other side. The
face side, reverse side, and cross-section views of the embossment
design of the interlayer thus obtained are shown in FIG. 4.
EXAMPLE 6
[0194] Except that a grid embossment design was used for engraving
mills (mother mills) and the pitch of embossments of one of the
engraving mills was set to 200 .mu.m and that of the other
engraving mill to 400 .mu.m, the procedure of Example 4 was
otherwise repeated to manufacture an interlayer for a laminated
glass having a grid pattern of embossments on either side and
varying in the pitch of embossments from one side to the other
side. The face side, reverse side, and cross-section views of the
embossment design of the interlayer thus obtained are shown in FIG.
5.
EXAMPLE 7
[0195] Except that a linear embossment design with a pitch of 220
.mu.m was used for one of the engraving mills (mother mills) and
the grid embossment design with a pitch of 320 .mu.m was used for
the other engraving mill, the procedure of Example 4 was otherwise
repeated to manufacture an interlayer for a laminated glass having
an orderly array of linear embossments on one side and an orderly
array of grid embossments on the other side and varying in the
pitch of embossments from one side to the other.
COMPARATIVE EXAMPLE 2
[0196] Except that a linear embossment design with a pitch of 210
.mu.m was used for both engraving mills (mother mills), the
procedure of Example 4 was otherwise repeated to manufacture an
interlayer for a laminated glass having an orderly linear
embossment pattern on both sides at the same pitch of embossments
for both sides. The face side, reverse side, and cross-section
views of the embossment design of the interlayer thus obtained are
shown in FIG. 6.
[0197] Using the 9 kinds of interlayers obtained in Examples 1 to 7
and Comparative Examples 1 and 2, respectively, the average surface
roughness (Rz) and average pitch (Sm) of embossments on each side
were measured by the following methods. The results are shown in
Table 1 and Table 2.
[0198] (Measurement of Rz)
[0199] Using a digital tracer system electric surface roughness
analyzer (trade name "SE-2000", manufactured by Kosaka Kenkyusho)
and a conical tracer (tip radius of curvature 5 .mu.m, vertex angle
90 degrees), the 10-point average surface roughness {Rz (.mu.m) }
of the embossment design on each side of the interlayer was
measured in accordance with JIS B0601.
[0200] (Measurement of Sm)
[0201] Under the microscope, the average pitch {Sm (.mu.m)} of
embosses on each side of the interlayer was measured.
[0202] Furthermore, with each of said 9 kinds of interlayers, the
appearance of the moir phenomenon was evaluated by the following
method. The results are shown in Table 1 and Table 2.
[0203] (Appearance of the Moir Phenomenon)
[0204] The interlayer was moved slowly and continuously and the
appearance of the moir phenomenon was visually monitored.
[0205] Then, using each of said 9 kinds of interlayers, preliminary
contact bonding was carried out by the following two alternative
methods (draw deaeration and vacuum deaeration), followed by final
contact bonding to fabricate 9 kinds of laminated glass sheets.
[0206] (a) Draw Deaeration
[0207] The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long.times.30 cm wide.times.3 mm
thick) and the superfluous part was trimmed off. The resulting
assembly was heated in an oven to an article temperature
(preliminary contact bonding temperature) of 60.degree. C.,
70.degree. C. or 80.degree. C. and passed over a nip roll (air
cylinder pressure 350 kPa, linear velocity 10 m/min) for
preliminary contact bonding.
[0208] (b) Vacuum Deaeration
[0209] The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long.times.30 cm wide.times.3 mm
thick) and the superfluous part was trimmed off. The resulting
assembly was transferred into a rubber bag and, with the rubber bag
connected to a suction system, heated by external heating while
maintaining at a negative pressure of -60 kPa (absolute pressure 16
kPa) for 10 minutes. After the assembly had been heated to an
article temperature (preliminary contact bonding temperature) of
60.degree. C., 80.degree. C. or 100.degree. C., the pressure was
returned to atmospheric pressure to complete preliminary contact
bonding.
[0210] The assembly subjected to preliminary contact bonding by the
above method (a) or (b) was held in an autoclave at a temperature
of 140.degree. C. and a pressure of 1.3 MPa for 10 minutes, at the
end of which time the temperature was lowered to 50.degree. C. and
the pressure was returned to atmospheric pressure to complete the
final contact bonding and provide a laminated glass.
[0211] The 9 kinds of laminated glass obtained as above were
subjected to a bake test according to the following protocol and
the deaeration performance of preliminary contact bonding was
evaluated. The results are shown in Table 1 and Table 2.
[0212] (Bake Test of Laminated Glass)
[0213] The laminated glass was heated in an oven at 140.degree. C.
for 2 hours. Then, the glass was taken out of the oven, allowed to
cool over 3 hours, and was visually inspected to count the number
of sheets with air bubbles and evaluate the deaeration performance.
The number of sheets tested was 100 for each glass product. The
fewer the number of glass sheets with air bubbles is, the superior
is the deaeration and sealing performance.
1 TABLE 1 Example 1 Example 2 Example 3 Compar. Ex. Embossment
Embossment design Linear Linear Linear Linear of interlayer
Embossment arrangement Orderly Orderly Orderly Orderly Face Average
surface roughness: Rz (.mu.m) 36.2 43.2 44.5 40.6 side Average
pitch: Sm (.mu.m) 252.0 302.2 303.0 305.0 Reverse Average surface
roughness: Rz (.mu.m) 42.5 43.0 39.4 41.2 side Average pitch: Sm
(.mu.m) 324.0 372.5 431.2 305.0 Incidence of moir No No No Yes
Preliminary contact Draw deaeration 60 70 80 60 70 80 60 70 80 60
70 80 bonding temperature (.degree. C.) Vacuum deaeration 60 80 100
60 80 100 60 80 100 60 80 100 Bake test of laminated glass Draw
deaeration 0 1 0 2 0 0 0 1 0 0 2 0 (the number of sheets with air
Vacuum deaeration 1 0 0 0 0 0 1 0 1 1 0 0 bubbles/100 sheets)
[0214]
2 TABLE 2 Example 4 Example 5 Example 6 Example 7 Compar. Ex. 2
Embossment Embossment design Face side Hemispherical Linear Grid
Linear Linear of interlayer Reverse side Hemispherical Linear Grid
Grid Linear Embossment arrangement Orderly Orderly Orderly Orderly
Orderly Average surface Face side 36.2 43.2 44.5 42.5 40.6
roughness: Rz (.mu.m) Reverse side 42.5 43.0 39.4 40.6 41.2 Average
pitch: Face side 210.0 255.2 213.0 220.4 215.0 Sm (.mu.m) Reverse
side 310.0 302.5 421.2 320.2 210.2 Incidence of moir No No No No
Yes Preliminary contact Draw 60 70 80 60 70 80 60 70 80 60 70 80 60
70 80 bonding temperature (.degree. C.) deaeration Vacuum 60 80 100
60 80 100 60 80 100 60 80 100 60 80 100 deaeration Bake test of
laminated glass Draw 0 1 0 2 0 0 0 1 0 0 1 1 0 2 0 (the number of
sheets with air deaeration bubbles/100 sheets) Vacuum 1 0 0 0 0 0 1
0 1 2 0 0 1 0 0 deaeration
[0215] It is apparent from Tables 1 and 2 that the interlayers for
laminated glass according to Examples 1 to 7 of the invention were
invariably free of the moir phenomenon. This result indicates good
workability in cutting and laminating operations. Furthermore, the
laminated glass products using the above interlayers according to
Examples 1 to 7 invariably showed few sheets with air bubbles
(rejects) in the bake test, regardless of the preliminary contact
bonding temperature used in the draw deaeration process or the
vacuum deaeration processes. These results indicate an invariably
satisfactory deaeration performance in preliminary contact
bonding.
[0216] In contrast, the interlayer for a laminated glass according
to Comparative Example 1 as manufactured using a pair of embossing
rolls fabricated from two engraving mills (mother mills) with the
same pitch of embossments (300 .mu.m) and the interlayer for a
laminated glass according to Comparative Example 2 as manufactured
by using a pair of embossing rolls fabricated from two engraving
mills (mother mills) with the same embossment design (linear) and
pitch were both good in deaeration performance at preliminary
contact bonding but developed the moir phenomenon. These results
are indicative of poor workability in cutting and laminating
operations.
EXAMPLE 8
[0217] As the thermoplastic resin sheet, "DXN film" (polyvinyl
butyral resin sheet, product of Sekisui Chemical) was used.
[0218] A pair of rolls, namely a metal roll subjected to surface
milling with a triangular oblique line type mill (product of Yuri
Roll Co.) and a rubber roll having a JIS hardness of 45 to 75, was
used as the surface irregularity transfer device and said DXD film
was passed over this surface irregularity transfer device to apply
an embossed depression forming a trough design with a continual
bottom on one side of the DXN film. The transfer conditions used
were as follows.
[0219] Temperature of DXN film: room temperature
[0220] Roll temperature: 130.degree. C.
[0221] Linear velocity: 10 m/min.
[0222] Press linear pressure: 500 kPa
[0223] Then, the other side of the DXN film was also subjected to
the above treatment to give an interlayer having an orderly linear
pattern comprising concave portions with a trough-like
configuration-continual at the bottom and convex portions each
having a plateau-forming top on both sides. The interval (pitch) of
the embossed convex portions of the interlayer was 300 .mu.m, the
width of the plateau-forming top of the embossed convex portion was
250 .mu.m, and the width of the embossed concave portion was 50
.mu.m.
EXAMPLE 9
[0224] Except that the pitch of the embossed convex portions was
set to 300 .mu.m, the width of the plateau-forming top of the
embossed convex portion was set to 160 .mu.m, and the width of the
embossed concave portion was set to 140 .mu.m, the procedure of
Example 8 was otherwise repeated to give an interlayer having an
orderly linear pattern comprising embossed concave portions having
a trough-like configuration continual at the bottom and embossed
convex portions each having a plateau-forming top on both
sides.
[0225] The embossment design (concave and convex patterns) of the
interlayers obtained in Example 8 and Example 9 is schematically
depicted in FIG. 7.
EXAMPLE 10
[0226] Except that the interval (pitch) of the embossed convex
portions was set to 200 .mu.m, the width of the plateau-forming top
of the embossed convex portion was set to 50 .mu.m, the width of
the embossed concave portion was set to 150 .mu.m, and a grid
configuration was selected for the embossment design, the procedure
of Example 8 was otherwise repeated to give an interlayer having an
orderly grid embossment pattern comprising embossed concave
portions having a trough-like configuration continual at the bottom
and embossed convex portions each having a plateau-forming
configuration on both sides.
EXAMPLE 11
[0227] Except that the interval (pitch) of the embossed convex
portions was set to 500 .mu.m, the width of the plateau-forming top
of the embossed convex portion was set to 400 .mu.m, the width of
the embossed concave portion was set to 100 .mu.m, and a grid
configuration was selected for the emboss design, the procedure of
Example 8 was otherwise repeated to give an interlayer having an
orderly grid embossment pattern comprising embossed concave
portions having a trough-like geometry continual at the bottom and
embossed convex portions each having a plateau-forming top on both
sides.
[0228] The embossment design (concave and convex patterns) of the
interlayers obtained in Example 10 and Example 11 is schematically
depicted in FIG. 8.
COMPARATIVE EXAMPLE 3
[0229] Except that the top of the embossed convex portion was not
made a plateau and the pitch of embossed convex portions and the
width of the embossed concave portion were set to 200 .mu.m, the
procedure of Example 8 was otherwise repeated to give an interlayer
having an orderly linear emboss pattern comprising embossed concave
portions having a trough-like geometry continual at the bottom and
embossed convex portions with tops not forming a plateau on both
sides. The embossment pattern (concave and convex patterns) of the
interlayer obtained in this Comparative Example is schematically
depicted in FIG. 9.
[0230] With the 5 kinds of interlayers obtained in Examples 8 to 11
and comparative Example 3, the average surface roughness (Rz) of
the embossment was measured by the same method as in Example 1. The
results are shown in Table 3.
[0231] Using each of the above 5 kinds of interlayers, the
preliminary contact bonding by the vacuum deaeration method and the
final contact bonding were serially carried out in the following
manner to construct 5 kinds of laminated glass products.
[0232] (Vacuum Deaeration)
[0233] The interlayer was sandwiched between two transparent float
glass sheets (30 cm long.times.30 cm wide.times.30 cm thick) and
the superfluous part was trimmed off to fabricate a
glass-interlayer assembly. The assembly was transferred into a
rubber bag. The rubber bag was connected to a vacuum suction system
and heated externally and held at a negative pressure of -60 kPa
(absolute pressure 16 kPa) for 10 minutes. The heating was
performed until the temperature of the assembly (preliminary
contact bonding temperature) had reached 70.degree. C. and the
pressure was then returned to atmospheric pressure to complete
preliminary contact bonding. The three different deaeration start
temperatures of 40.degree. C., 50.degree. C. and 60.degree. C. were
used at preliminary contact bonding.
[0234] (Final Contact Bonding)
[0235] The glass assembly subjected to preliminary contact bonding
in the above manner was placed in an autoclave and held at a
temperature of 140.degree. C. and a pressure of 1300 kPa for 10
minutes. The temperature was then lowered to 50.degree. C. and the
pressure was returned to atmospheric pressure to complete final
contact bonding and give a laminated glass.
[0236] The 5 kinds of laminated glass sheets obtained as above were
respectively subjected to a bake test in the same manner as in
Example 1 to evaluate the deaeration performance at preliminary
contact bonding. The results are shown in Table 3.
3 TABLE 3 Example Example Example Example Compar. 8 9 10 11 Ex. 3
Embossment Embossment design Linear Linear Grid Grid Linear of
interlayer Embossment arrangement (distribution) Orderly Orderly
Orderly Orderly Orderly Embossment Pitch of convex portions 300 300
200 500 200 geometry (a: .mu.m) Width of flat part of convex
portions 250 160 50 400 -- (b: .mu.m) b/a (%) 83.3 53.3 25.0 80.0
-- Width of concave portions (c: .mu.m) 50 140 150 100 200 Average
surface roughness 42.5 40.5 45.2 41.2 60.2 (Rz: .mu.m) Results of
Condtions of Initial vacuum temperature (.degree. C.) 40 50 60 40
50 60 40 50 60 40 50 60 40 50 60 evaluation vacuum Preliminary
contact 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 deaeration
bonding temperature (.degree. C.) Bake test of laminated glass 0 0
1 0 1 5 1 5 10 1 0 1 10 50 90 (the number of sheets with air
bubbles/100 sheets)
[0237] It is apparent from Table 3 that the laminated glass sheets
manufactured by using the interlayers according to Examples 8 to 11
of the invention showed few sheets with air bubbles (rejects) in
the bake test invariably at the deaeration start temperatures of
40.degree. C., 50.degree. C. and 60.degree. C. in the preliminary
contact bonding by the vacuum deaeration method. The result
indicates that good deaeration was obtained even without critical
control of deaeration start temperature in preliminary contact
bonding and even at the ordinary preliminary contact bonding
temperature (70.degree. C.), not a deliberately increased
preliminary contact bonding temperature.
[0238] In contrast, the laminated glass manufactured by using the
interlayer of Comparative Example 3 where the top of the embossed
convex portion was not flattened to a plateau gave quite many
sheets with air bubbles (rejects) in the bake test when the
deaeration start temperature in preliminary contact bonding was
50.degree. C. or higher. This result indicates that unless the
deaeration start temperature in preliminary contact bonding is
strictly controlled to at least below 50.degree. C., the premature
sealing takes place around the edge of the glass-interlayer
assembly to interfere with a thorough removal of air in the central
part, of the assembly.
EXAMPLES 12 to 16
[0239] (Preparation of the Interlayer for a Laminated Glass)
[0240] For embossing, a variety of embossing rolls were provided.
As the thermoplastic resin sheets, DXN films (polyvinyl butyral
resin sheet, product of Seisui Chemical) was provided. The Ra
values of the DXN films used in Examples 12 to 16 are shown in
Table 4.
[0241] Using a pair of rolls, namely an embossing roll and a rubber
roll, as the surface irregularity transfer device, the above DXN
film was passed over this surface irregularity transfer device to
give an interlayer for a laminated glass having an embossment
pattern on both sides. The transfer conditions used are as
follows.
[0242] Temperature of DXN film: room temperature
[0243] Roll temperature: 130.degree. C.
[0244] Linear velocity: 10 m/min
[0245] Press linear pressure: 500 kPa
[0246] The embossment patterns (concave and convex patterns) of the
interlayers for laminated glass as obtained in Examples 12 to 16
are shown in Table 4.
[0247] FIG. 10 shows the embossment pattern (concave and convex
patterns) of the interlayers for laminated glass as obtained in
Example 12 and Example 13; FIG. 11 shows the embossment pattern
(concave and convex patterns) of the interlayers for laminated
glass as obtained in Example 14 and Example 15; and FIG. 12 shows
the embossment pattern (concave and convex patterns) of the
interlayer for a laminated glass as obtained in Example 16.
COMPARATIVE EXAMPLE 4
[0248] (Production of the Interlayer for a Laminated Glass)
[0249] Except that the routinely extruded non-embossed sheet
(polyvinyl butyral resin sheet) was used as the thermoplastic resin
sheet, the procedure of Examples was otherwise repeated to give an
interlayer for a laminated glass having an embossment pattern on
both sides.
[0250] The embossment pattern (concave and convex patterns) of the
interlayer for a laminated glass as obtained in Comparative Example
4 is shown in Table 4.
[0251] FIG. 13 is a schematic representation of the embossment
pattern (concave and convex patterns) of the interlayer for a
laminated glass as obtained in Comparative Example 4.
[0252] For each of the six kinds of interlayers for laminated glass
as obtained in Examples and Comparative Example, the average
surface roughness (Ra) of the embossment was measured by the method
described below and the average surface roughness (Rz) was measured
as in Example 1 for the evaluation of handling workability and
self-adhesiveness of the interlayer. The results are shown in Table
4.
[0253] (Measurement of Ra)
[0254] Using a digital tracer-type electric surface roughness
analyzer (trade name SE-2000, product of Kosaka Kenkyusho) with a
wedge-shaped tracer (tip width 1000 .mu.m, facial angle
90.degree.), the 10-point average surface roughness {Ra (.mu.m) }
of the emboss on each side of the interlayer for a laminated glass
was measured in accordance with JIS B 0601.
[0255] Moreover, using each of the above six kinds of interlayers
for laminated glass, preliminary contact bonding by the vacuum
deaeration technique and final contact bonding were carried out
serially as in Example 8 to manufacture six kinds of laminated
glass.
[0256] These six kinds of laminated glass were respectively
subjected to a bake test under the same conditions as in Example 1
to evaluate the deaeration performance in preliminary contact
bonding. The results are shown in Table 4.
4 TABLE 4 Example Compar. Ex. 12 13 14 15 16 4 Embossment
Embossment design Linear Linear Linear Linear Linear Linear of
interlayer Embossment distribution Orderly, Orderly, Orderly,
Orderly, Orderly, rotated Orderly, parallel parallel parallel
parallel through 90.degree. parallel Embossment Pitch of main
convex 300 500 300 500 200 200 geometry portions (a: .mu.m) Width
of flat part of main 250 400 250 400 100 25 convex portions (b:
.mu.m) b/a (%) 83 83 80 83 50 12.5 Width of main concave 50 100 50
100 100 175 portions (c: .mu.m) Average surface roughness, 42.5
40.5 45.2 41.2 50.2 55.6 5 .mu.m tracer (Rz: .mu.m) Average surface
roughness, 4.1 3.5 2.7 2.0 2.0 0.5 1000 .mu.m Tracer (Ra: .mu.m)
Results of Self-adhesive strength (g/15 cm) 350 420 570 980 650
2540 evaluation Condtions Initial vacuum temperature 40 50 60 40 50
60 40 50 60 40 50 60 40 50 60 40 50 60 of (.degree. C.) vacuum
Preliminary contact 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70 70
70 70 deaeration bonding temperature (.degree. C.) Bake test of
laminated glass (the number 0 0 1 0 1 2 1 1 2 2 2 4 3 4 5 4 10 20
of sheets with air bubbles/100 sheets)
[0257] It is apparent from Table 4 that the laminated glass sheets
manufactured in the above Examples showed fewer sheets with air
bubbles (rejects) due to bubbling in the bake test when the
deaeration start temperature in preliminary contact bonding by the
vacuum deaeration technique was any of 40.degree. C., 50.degree.
C., and 60.degree. C. This result indicates that good deaeration
was obtained even when the deaeration temperature was not
critically controlled or even when preliminary contact bonding was
carried out at an ordinary preliminary contact bonding temperature
(70.degree. C.) without using a deliberately raised preliminary
contact bonding temperature. Furthermore, the interlayers for
laminated glass according to Examples 15 and 16 where the Ra of the
plateau of the convex portion was less than 2.5 .mu.m showed
slightly higher self-adhesiveness than the interlayers for
laminated glass according to Examples 12 to 14 but was of the order
which does not matter from practical points of view.
[0258] On the other hand, the interlayer for a laminated glass
having no fine irregularities according to Comparative Example in
which the ratio (b/a) of the width of the plateau to the pitch of
convex portions was less than 20% showed exceedingly high
self-adhesiveness as compared with the interlayer for a laminated
glass according to the above Examples and the laminated glass
manufactured by using this interlayer for a laminated glass showed
many sheets with air bubbles (rejects) owing to bubbling in the
bake test as compared with the Examples when the deaeration start
temperature in preliminary contact bonding was 50.degree. C. or
higher. This result indicates that unless the deaeration start
temperature for preliminary contact bonding is strictly controlled
to at least below 50.degree. C., the premature marginal sealing of
the glass-interlayer assembly takes place so that the air present
in the central part of the assembly is not sufficiently
removed.
EXAMPLES 17 TO 20 AND COMPARATIVE EXAMPLE 5
[0259] For producing various embossment patterns, a variety of
embossing rolls were prepared.
[0260] A longitudinal pattern-engraving mill (mother mill) was
pressed against one metal roll of a pair of embossing rolls and the
metal roll and the engraving mill were driven in association to
transfer the concave and convex patterns of the engraving mill to
the metal roll. Then, the engraving mill was shifted serially in
the axial direction of the metal roll in steps of the unit design
of the concave and convex patterns to construct an embossing roll
carrying an orderly array of longitudinal linear patterns. Further,
in Example 19 and Example 20, a transverse pattern-engraving mill
was used to transfer the transverse design to said metal roll under
a load corresponding to {fraction (1/10)} of the transfer pressure
of said longitudinal-pattern, engraving mill. In this procedure,
the arrangement and size of the respective patterns were monitored
under the microscope.
[0261] As the thermoplastic resin sheet, "DXN film" (polyvinyl
butyral resin sheet, product of Sekisui Chemical) was used.
[0262] The above embossing roll was paired with a rubber roll and
with the embossing roll controlled at 130.degree. C., the above
thermosetting resin sheet was passed over the roll set to apply the
predetermined emboss pattern.
[0263] The embossed pattern formed on the interlayers for laminated
glass as obtained in Example 17 and Example 18 is illustrated in
FIG. 14; the embossed pattern formed on the interlayers for
laminated glass as obtained in Example 19 and Example 20 is
illustrated in FIG. 15; and the embossed pattern formed on the
interlayer for a laminated glass as obtained in Comparative Example
5 is illustrated in FIG. 16. The pitch of convex portions, depth of
troughs, pitch of segmenting walls, and height of the segmenting
wall of each embossment are shown in Table 5.
[0264] For each of the 5 kinds of interlayers obtained in Examples
17 to 20 and Comparative Example 5, the average surface roughness
(Rz) of the embossment was measured by the same method as used in
Example 1. The results are shown in Table 5.
[0265] Moreover, using each of the above 5 kinds of interlayers,
preliminary contact bonding by the vacuum deaeration technique and
final contact bonding were serially performed as described below to
manufacture 5 kinds of laminated glass sheets.
[0266] [Vacuum Deaeration Method]
[0267] The interlayer was sandwiched between two transparent sheets
of transparent float glass (30 cm long.times.30 cm wide.times.3 mm
thick) and the superfluous part was trimmed off. The resulting
glass-interlayer assembly was transferred into a rubber bag and the
rubber bag was connected to a vacuum suction system. The bag was
heated externally under a negative pressure of -60 kPa (absolute
pressure 16 kPa) for 10 minutes, whereby the temperature of the
glass-interlayer assembly (preliminary contact bonding temperature)
was brought to a predetermined temperature. The negative pressure
was then returned to atmospheric pressure to complete preliminary
contact bonding. The deaeration start temperature for the above
preliminary contact bonding was set to 50.degree. C. and the
preliminary contact bonding temperature was set to one of the three
levels, 60.degree. C., 65.degree. C., or 70.degree. C.
[0268] (Final Contact Bonding)
[0269] The glass-interlayer assembly provisionally bonded by the
above procedure was placed in an autoclave and held at a
temperature of 140.degree. C. and a pressure of 1300 kPa for 10
minutes. Then, the temperature was lowered to 50.degree. C. and the
pressure was returned to atmospheric pressure to complete final
contact bonding and thereby provide a laminated glass.
[0270] The resulting 5 kinds of laminated glass sheets were
respectively subjected to a bake test according to the same
protocol as used in Example 1 to evaluate the deaeration
performance in preliminary contact bonding. The results are shown
in Table 5.
5 TABLE 5 Example Compar. 17 18 19 20 Ex. 5 Embossment Embossment
design Linear Linear Grid Grid Linear of interlayer Embossment
arrangement Orderly Orderly Orderly Orderly Orderly Embossment
Pitch of convex portions (.mu.m) 350 500 350 500 350 geometry Depth
of concave portions (.mu.m) 50 50 50 50 50 Pitch of segmenting
walls (.mu.m) 500 500 1000 1000 -- Height of segmenting walls
(.mu.m) 25 25 25 25 -- Average surface roughness (Rz: .mu.m) 45.5
43.6 44.5 42.7 44.2 Results of Condtions of Initial vacuum
temperature (.degree. C.) 50 50 50 50 50 evaluation vacuum
Preliminary contact 60 65 70 60 65 70 60 65 70 60 65 70 60 65 70
deaeration bonding temperature (.degree. C.) Bake test of laminated
glass 5 4 1 2 2 1 4 3 2 5 3 2 30 15 5 (the number of sheets with
air bubbles/100 sheets)
EXAMPLE 21
[0271] The surface of a metal roll was machined with an engraving
mill (a linear triangular oblique line cup mill) to form concave
and convex patterns (orderly) comprising a multiplicity of concave
troughs (linear) triangular in section and the corresponding
multiplicity of convex ridges (linear). Further, using glass beads
(#46), the roll was blasted from a distance of about 30 cm at an
air pressure of 100 kPa to fabricate an embossing roll.
[0272] On the other hand, 100 parts by weight of polyvinyl butyral
resin (average degree of polymerization 1700, residual acetyl group
1 mol %, butyralization degree 65 mol %) was blended with 40 parts
by weight of the plasticizer triethylene glycol di-2-ethylbutyrate
and 0.2 part by weight of the bond strength modulator magnesium
acetate, and using an extruder, the resulting mixture was
melt-kneaded and extruded from a die in a sheet form to give a 0.76
mm-thick polyvinyl butyral sheet.
[0273] Using a pair of embossing rolls fabricated in the above
manner and the above polyvinyl butyral sheet, an interlayer was
produced by the conventional method, which interlayer consisted of
a polyvinyl butyral sheet and, as formed on both sides thereof,
concave and convex patterns (orderly) comprising a multiplicity of
convex ridges (linear) triangular in cross-section and the
corresponding multiplicity of convex troughs (linear), said troughs
being not on the same level. The water content of this interlayer
was adjusted to 0.4 to 0.5 weight %.
EXAMPLE 22
[0274] The surface of a metal roll was machined with an engraving
mill (pyramid cup mill) to form a multiplicity of concave portions
each in the form of a quadrangular pyramid and the corresponding
multiplicity of convex portions. The roll was further blasted with
glass beads (#20) from a distance of about 30 cm at an air pressure
of 100 kPa to fabricate an embossing roll.
[0275] Except that a pair of embossing rolls fabricated as above
was used, the procedure of Example 21 was otherwise repeated to
manufacture an interlayer comprising a polyvinyl butyral sheet and,
as formed on both sides thereof, concave and convex patterns
(orderly) comprising a multiplicity of convex portions each in the
form of a quadrangular pyramid and the corresponding multiplicity
of concave portions, with the respective concave portions being not
on the same level. In this example, the concave portion between
adjacent convex portions constituted a grid-like trough.
EXAMPLE 23
[0276] The surface of a metal roll was machined with an engraving
mill (wavy triangular oblique line cup mill) to form concave and
convex patterns (not orderly) comprising a multiplicity of concave
troughs (wavy) triangular in cross-section and the corresponding
multiplicity of complementary convex ridges (wavy). The roll was
further blasted with glass beads (#20) from a distance of about 30
cm at an air pressure of 1 kg to fabricate an embossing roll.
[0277] Except that a pair of embossing rolls fabricated in the
above manner was used, the procedure of Example 21 was otherwise
repeated to produce an interlayer comprising a polyvinyl butyral
sheet and, as formed on both sides thereof, concave and convex
patterns (not orderly) comprising a multiplicity of convex ridges
(wavy) triangular in cross-section and the corresponding
multiplicity of complementary concave troughs (wavy), with the
respective troughs being not on the same level.
COMPARATIVE EXAMPLE 6
[0278] The surface of a metal roll was machined with an engraving
mill (linear triangular oblique line cup mill) to form concave and
convex patterns (orderly) comprising a multiplicity of concave
troughs (linear) triangular in cross-section and the corresponding
multiplicity of complementary convex ridges (linear) to thereby
fabricate an embossing roll.
[0279] Except that the above embossing roll was used, the procedure
of Example 21 was otherwise repeated to produce an interlayer
comprising a polyvinyl butyral sheet and, as formed on both sides
thereof, concave and convex patterns (orderly) comprising a
multiplicity of convex ridges (linear) triangular in cross-section
and the corresponding multiplicity of complementary concave troughs
(linear), with the respective concave troughs being consistently on
the same level.
[0280] For each of the interlayers obtained in the above Examples
and Comparative Example, the surface roughness (Rz) of the emboss
design was measured by the same method as used in Example 1 and the
Rzv of the negative model of the embossment was measured by the
method described below. Moreover, using these interlayers,
laminated glass sheets were manufactured by the following method
and subjected to the same bake test as in Example 1 to evaluate
deaeration and sealing performances in the preliminary contact
bonding stage. The results are collectively shown in Table 6.
[0281] [Measurement of Rzv]
[0282] Using the general-purpose molding silicone RTV KE-20
(product of Shin-Etsu Chemical), the emboss negative model was
taken from each of the above interlayers and the surface roughness
Rzv of this negative model was measured using the wedge-shaped
tracer (tip width 1000 .mu.m, opposite face angle 90.degree.) by
scanning with the tracer shifted in the direction normal to its tip
width in accordance with JIS B 0601.
[0283] [Evaluation of Deaeration and Sealing Performances]
[0284] Preliminary contact bonding was performed by the following
alternative techniques (draw deaeration and vacuum deaeration) and
final contact drawing was then performed to manufacture laminated
glass sheets.
[0285] (a) Draw Deaeration Method
[0286] The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long.times.30 cm wide.times.2 mm
thick; the margin of each glass sheet was curved by 1 mm with
respect to the center) and the superfluous part of the interlayer
was trimmed off. The resulting glass-interlayer assembly was heated
in an oven until the temperature of the assembly (preliminary
contact bonding temperature) had reached 60.degree. C., 70.degree.
C. or 80.degree. C. and, then, passed over a pair of nip rollers
(air cylinder pressure 350 kPa, linear velocity 10 m/min) for
preliminary contact bonding.
[0287] (b) Vacuum Deaeration
[0288] The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long.times.30 cm wide.times.2 mm
thick; the margin of each panel is curved by 1 mm with respect of
the center) and the superfluous part of the interlayer was trimmed
off. The resulting glass-interlayer assembly was transferred into a
rubber bag and the rubber bag was connected to a vacuum suction
system. It was then heated externally and held at a negative
pressure of -60 kPa (absolute pressure 16 kPa) for 10 minutes, the
heating being carried out until the temperature of the assembly
(preliminary contact bonding temperature) reached 60.degree. C.,
80.degree. C. or 100.degree. C. Then, the pressure was returned to
atmospheric pressure to complete preliminary contact bonding.
[0289] The assemblies obtained by the above techniques (a) and (b)
were respectively held in an autoclave at a temperature of
140.degree. C. and a pressure of 1.3 MPa for 10 minutes, after
which the temperature was lowered to 50.degree. C. and the pressure
returned to atmospheric pressure for final contact bonding to give
laminated glass.
6 TABLE 6 Example 21 Example 22 Example 23 Compar. Ex. 6
Configuration of convex portion Triangular Quadrangular Triangular
Triangular Configuration of troughs Linear Grid Wavy Linear
Arrangement Orderly Orderly Not orderly Orderly Surface roughness
of embossment, Rz (.mu.m) 48.5 46.4 52.1 53.4 Surface roughness of
negative model, Rzv (.mu.m) 12.2 12.9 13.6 9.5 Rzv/Rz 0.252 0.278
0.261 0.178 Preliminary contact bonding temperature (.degree. C.)
Draw roll method 60 70 80 60 70 80 60 70 80 60 70 80 Vacuum bag
method 60 80 100 60 80 100 60 80 100 60 80 100 Bake test of
laminated glass (the number of sheets with air bubbles/100 sheets)
Draw roll method 4 2 0 5 2 0 5 2 0 45 22 0 Vacuum bag method 3 1 0
2 2 0 4 1 0 15 6 0
[0290] As the thermoplastic resin sheet, DX film (product of
Sekisui Chemical) was used.
[0291] Using a pair of rolls, namely a metal roll machined with a
triangular oblique line mill (75 mesh, 80 depth, manufactured by
Yuri Roll Co.) and a rubber roll having a JIS hardness of 45 to 75,
as the surface irregularity transfer device, the DX film was passed
through the surface irregularity transfer device to form a
trough-shaped embossment pattern of continual concave portions on
one side of the DX film. The transfer conditions were as
follows.
[0292] Temperature of DX film: room temperature
[0293] Roll temperature: 140.degree. C.
[0294] Linear velocity: 10 m/min. 4
[0295] Press linear pressure: 2500 kPa
[0296] Then, using a pair of rolls, namely a metal roll machined
with said triangular oblique line mill and a reverse triangular
oblique line mill (75 mesh, 80 depth, manufactured by Yuri Roll
Co.), and a rubber roll having a JIS hardness of 45 to 75, as the
surface irregularity transfer device, the above-mentioned DX film
formed with a trough pattern on one side was passed through this
surface irregularity transfer device to apply a grid-form
segmenting pattern to the continual ridge pattern. The transfer
conditions used here were as follows.
[0297] Temperature of DX film: room temperature
[0298] Roll temperature: 110.degree. C.
[0299] Linear velocity: 10 m/min.
[0300] Press linear pressure: 2000 kPa
[0301] Then, the other side of the DX film was subjected to the
same treatment as above to give an interlayer for a laminated glass
having an embossment pattern comprising embossed concave portions
with a continual trough-like geometry and embossed convex portions
with segmented portions on both sides.
EXAMPLE 25
[0302] Except that the transfer conditions for applying a grid-form
segmenting pattern to the continual embossed convex portions were
altered to those mentioned below, the procedure of Example 24 was
otherwise repeated to give an interlayer for a laminated glass
having an embossment pattern comprising embossed concave portions
with continual trough-like geometry and embossed convex portions
with segmented portions on both sides.
[0303] Temperature of DX film: room temperature
[0304] Roll temperature: 120.degree. C.
[0305] Linear velocity: 10 m/min.
[0306] Press linear pressure: 2000 kPa
EXAMPLE 26
[0307] Except that the following conditions (1) were used in the
transfer operation for applying an embossment comprising continual
trough-like geometry of concave portions and the following
conditions (2) in the transfer operation for applying a grid-like
segmenting pattern to the continual convex portion of the
embossment, the procedure of Example 24 was otherwise repeated to
give an interlayer for a laminated glass having an embossment
comprising embossed concave portions with continual trough-like
geometry and embossed convex portions with segmented portions on
both sides.
[0308] Condition (1)
[0309] Temperature of DX film: room temperature
[0310] Roll temperature: 120.degree. C.
[0311] Linear velocity: 10 m/min.
[0312] Press linear pressure: 2500 kPa
[0313] Condition (2)
[0314] Temperature of DX film: room temperature
[0315] Roll temperature: 130.degree. C.
[0316] Linear velocity: 10 m/min.
[0317] Press linear pressure: 2000 kPa
COMPARATIVE EXAMPLE 7
[0318] Except that the grid-form segmenting pattern was not applied
to the continual convex portion of the embossment, the procedure of
Example 24 was otherwise repeated to give an interlayer for a
laminated glass having an embossment comprising embossed concave
portion with a continual trough-like geometry and embossed convex
portions without segmented portions on both sides.
[0319] The characteristics [(1) average surface roughness (Rz), (2)
slip test, (3) antiblocking properties, (4) bake test] of the four
kinds of interlayers for laminated glass as obtained in Examples 24
to 26 and Comparative Example 7 were evaluated by the following
methods. The results are shown in Table 7.
[0320] (1) Average Surface Roughness (Rz)
[0321] This parameter was measured in the same manner as in Example
1.
[0322] (2) Slip Test
[0323] The interlayer cut to 50 cm.times.50 cm was placed in
horizontal position on a smooth-surfaced glass plate (50 cm
long.times.50 cm wide) and a slip glass sheet (10 cm long.times.10
cm wide.times.2.5 mm thick) was placed in superposition. After 30
seconds, the slip glass sheet was pulled horizontally with a spring
balance and the maximum frictional resistance was determined from
the spring scale reading. The measurement was made in 5 replicates
and the average value was taken as maximum frictional resistance
(g). The measurement was performed in an atmosphere of 20.degree.
C., 40% RH. The smaller the maximum frictional resistance value is,
the superior is the slippage between the glass sheet and the
interlayer, which means that the relative positioning of the glass
sheet and the interlayer is facilitated in the laminating operation
and hence the handling workability is improved.
[0324] (3) Antiblocking Properties
[0325] Two sheets of the interlayer cut to 15 cm.times.15 cm were
set one on the other and a weight of 13 kg was put on the sheets.
After 24 hours of standing at room temperature, an angular peel
test was performed using a tensile tester at a pulling speed of 500
mm/min to measure the peel strength. The measurement was carried
out in 5 replicates and the average result was taken as peel
strength (g). The smaller this peel strength value is, the less
ready is the sheet-to-sheet self-adhesion of the interlayer, which
means superior antiblocking properties and better workability in
storage and in the operation for interposing the interlayer between
glass sheets.
[0326] (4) Bake Test
[0327] Preliminary contact bonding was performed by the two
alternative techniques, viz. (a) draw deaeration and (b) vacuum
deaeration, just as in Example 21, followed by final contact
bonding to produce laminated glass sheets and these sheets were.
subjected to the bake test.
7 TABLE 7 Example 24 Example 25 Example 26 Compar. Ex. 7 Embossment
of Concave Geometry Grid of troughs Grid of troughs Grid of troughs
Linear troughs interlayer portion Arrangement Orderly Orderly
Orderly Orderly Convex Segmentation Segmented Segmented Segmented
Not segmented portion Depth of segmenting trough Shallow Slightly
deep Deep -- Performance Average surface roughness (Rz: .mu.m) 38.2
42.2 46.1 56.5 characteristics Slip properties (max. frictional
resistance: g) 265 255 225 302 of interlayer Antiblocking
properties (peel strength: g) 420 415 380 440 Bake test Preliminary
contact Draw deaeration 60 70 80 60 70 80 60 70 80 60 70 80 bonding
temperature (.degree. C.) Vacuum deaeration 60 80 100 60 80 100 60
80 100 60 80 100 the number of sheets with Draw deaeration 2 1 0 4
1 0 6 2 0 20 10 0 air bubbles/100 sheets Vacuum deaeration 1 0 0 2
1 0 4 3 0 25 15 0
[0328] It will be apparent from Table 7 that the interlayers for
laminated glass according to Examples 24 to 26 of the invention
invariably have excellent slip and antiblocking properties. This
means that these interlayers provide for good workability in
handing during storage and glass processing.
[0329] Furthermore, the laminated glass sheets of Examples 24 to 26
as manufactured by using the interlayers according to Examples 24
to 26 showed fewer sheets with air bubbles (fewer rejects) in the
bake test, regardless of the preliminary contact bonding
temperature used in the draw deaeration process or in the vacuum
deaeration process. These results indicate good deaeration and
sealing in the preliminary contact bonding stage.
[0330] In contrast, the laminated glass of Comparative Example 7
which was manufactured by using the interlayer for a laminated
glass according to Comparative Example 7 without providing
segmentation to convex portions of the embossment showed many
sheets with air bubbles (many rejects) in the bake test when the
preliminary contact bonding temperature was low, whether in the
draw deaeration process or in the vacuum deaeration process. This
means that the sealing in the preliminary contact bonding stage was
not wholesome, thus causing insufficient deaeration. Moreover, the
result indicates that there are limitations on the manufacturing
conditions which can be used in the preliminary contact bonding
stage.
EXAMPLE 27
[0331] FIG. 20 shows an interlayer embodying the principles of the
present invention, where (a) is a plan view and (b) is a side
elevation view.
[0332] As shown in FIG. 20, the interlayer 1 of the invention
comprises an extrusion-molded thermoplastic resin sheet provided
with a plurality of embossments 3 comprising fine concave portions
and convex portions (not shown) on both sides and concave troughs 2
on one side, said concave troughs 2 being disposed generally in
parallel with the direction of extrusion X of the thermoplastic
resin sheet.
[0333] (Production of an Interlayer)
[0334] A thermoplastic resin sheet as obtained by extrusion of
plasticized polyvinyl butyral resin (product of Sekisui Chemical;
trade name "S-Rec Film DXN", 760 .mu.m thick) was passed through a
surface irregularity transfer device comprising a pair of rolls,
namely a metal roll formed with prismatic ridges (height: 120
.mu.m, base 150 .mu.m, pitch: 300 .mu.m) complementary with the
concave troughs 2 illustrated in FIG. 20 in axial continuum and
random concave and convex patterns in the regions other than said
ridges, and a rubber roll having a JIS hardness of 45 to 75 with
random concave and convex patterns, to fabricate an interlayer
having concave troughs 2 each in a continuum parallel to the
extrusion direction of the sheet on one side thereof and embossed
concave and convex patterns on both sides. The transfer conditions
used here were as follows.
[0335] Temperature of DX film: room temperature
[0336] Roll temperature: 120.degree. C.
[0337] Linear velocity: 10 m/min.
[0338] Press linear pressure: 500 kPa
COMPARATIVE EXAMPLE 8
[0339] Except that the prismatic ridges of the metal roll were
disposed at an angle of 45.degree. with the axial direction, the
procedure of Example 27 was otherwise repeated to fabricate an
interlayer.
COMPARATIVE EXAMPLE 9
[0340] Except that the prismatic ridges of the metal roll were
disposed in the circumferential direction, the procedure of Example
27 was otherwise repeated to fabricate an interlayer.
COMPARATIVE EXAMPLE 10
[0341] Except that V-shaped concave troughs were provided in the
circumferential direction in lieu of the prismatic ridges of the
metal roll, the procedure of Example 27was otherwise repeated to
fabricate an interlayer.
[0342] The interlayers obtained in Example 27 and Comparative
Examples 8 to 10 were evaluated as follows. (10-Point average
surface roughness {Rz (.mu.m)})
[0343] This parameter was measured by the same method as in Example
1.
[0344] (Bake Test)
[0345] Preliminary contact bonding by the following alternative
techniques, (a) draw deaeration and (b) vacuum deaeration, and
final contact bonding were serially carried out to manufacture
laminated glass sheets.
[0346] (a) Draw Deaeration
[0347] The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long.times.30 cm wide.times.2 mm
thick; glass sheets with the margin curved by 1 mm with respect to
the center) and the superfluous part was trimmed off. The resulting
assembly was heated in an oven until the temperature of the
assembly had reached 70.degree. C., 80.degree. C. or 90.degree. C.
and, then, passed over a nip roll (air cylinder pressure 35.5 MPa,
linear velocity 10 m/min) for preliminary contact bonding.
[0348] (b) Vacuum Deaeration
[0349] The interlayer was sandwiched between two sheets transparent
float glass (30 cm long.times.30 cm wide.times.2 mm thick; glass
sheets with the margin curved by 1 mm with respect to the center)
and the superfluous part was trimmed off. The resulting assembly
was transferred into a rubber bag and the rubber bag was connected
to a vacuum system. The assembly was heated externally under a
negative pressure of -60 kPa (absolute pressure 16 kPa) for 10
minutes until the temperature of the assembly (preliminary contact
bonding temperature) had reached 70.degree. C., 80.degree. C. or
90.degree. C. The pressure was then returned to atmospheric
pressure to complete preliminary contact bonding.
[0350] The glass-interlayer assemblies subjected to preliminary
contact bonding in the above processes (a) and (b), respectively,
were held in an autoclave at a temperature of 140.degree. C. and a
pressure of 1.3 MPa for 10 minutes, after which the temperature was
lowered to 50.degree. C. and the pressure returned to atmospheric
pressure to complete final contact bonding to give laminated
glass.
[0351] The laminated glass sheets obtained as above were subjected
to the bake test under the same conditions as in Example 1.
8 TABLE 8 Example Compar. Ex. 27 8 9 10 10-point average surface
roughness (.mu.m) 35.5 37.8 40.2 64.2 Bake test Draw Temperature
70.degree. C. 1 4 3 14 the number of deaeration 80.degree. C. 1 2 4
8 sheets with air 90.degree. C. 0 1 2 11 bubbles/100 Vacuum
Temperature 70.degree. C. 0 0 1 1 sheets deaeration 80.degree. C. 0
1 0 2 90.degree. C. 1 0 1 0
[0352] a surface roughness of about 60 .mu.m, was coated with a
lubricant and a geometric transfer was made to the surface of a
substrate interlayer sheet at 100.degree. C. to give an interlayer
having a random emboss pattern with a surface roughness of 30
.mu.m. The surface of another metal roll was impressed with a
triangular mill to form 200 .mu.m-deep troughs on the surface of
the metal roll and further impressed with a perpendicular
triangular mill to prepare a roll surface reduced by 15 .mu.m in
depth of the troughs (corresponding to the bottom surface in the
interlayer). Then, this roll surface was geometrically transferred
to the surface of the interlayer having said random embossment to
give an interlayer having 40 .mu.m-deep, 80 .mu.m-wide troughs at a
pitch of 500 .mu.m within 55 .mu.m-deep, 60 .mu.m-wide troughs
formed at a trough pitch of 300 .mu.m.
EXAMPLE 29
[0353] Except that the pressure used for the geometric transfer of
the metal roll surface to the substrate interlayer surface was
altered, the procedure of Example 28 was otherwise repeated to give
an interlayer having a random embossment with a roughness of 30
.mu.m as well as 50 .mu.m-deep, 70 .mu.m-wide troughs formed at a
pitch of 500 .mu.m within 55 .mu.m-deep, 60 .mu.m-wide troughs.
COMPARATIVE EXAMPLE 11
[0354] The pressure used for the geometric transfer of the metal
roll surface to the substrate interlayer surface was altered and
the troughs were not formed, the procedure of Example 28 was
repeated to give an interlayer having a random embossment with a
surface roughness of 55 .mu.m.
COMPARATIVE EXAMPLE 12
[0355] Except that the troughs were not formed, the procedure of
Example 28 was otherwise repeated to give an interlayer having a
random embossment with a surface roughness of 30 .mu.m.
COMPARATIVE EXAMPLE 13
[0356] A metal roll was machined to form the embossing pattern
consisting of a uniform array of quadrangular pyramids and the
surface of this metal roll was geometrically transferred to a
substrate interlayer sheet surface to give an interlayer with a
surface roughness of 70 .mu.m.
COMPARATIVE EXAMPLE 14
[0357] Except that the pressure used for the geometric transfer of
the metal roll surface to the interlayer sheet surface was altered,
the procedure of Comparative Example 13 was otherwise repeated to
give an interlayer with a surface roughness of 35 .mu.m.
COMPARATIVE EXAMPLE 15
[0358] The procedure of Example 28 was repeated to give an
interlayer having a random emboss pattern with a surface roughness
of 30 .mu.m. Then, an iron roll surface with ridge-shaped troughs
was constructed and a geometric transfer was carried out from this
roll surface to the interlayer surface having the above random
embossment to give an interlayer having 55 .mu.m-deep, 60
.mu.m-wide triangular wavy troughs at a pitch of 300 .mu.m.
[0359] The performances (deaeration characteristics) of the
interlayers obtained in the above Examples and Comparative Examples
were evaluated by the following method. The results are shown in
Table 9.
[0360] (Evaluation of Deaeration Characteristic)
[0361] Each interlayer was sandwiched between two transparent 2
mm-thick glass sheets and the resulting glass-interlayer assembly
was put in a rubber bag set to the initial temperature indicated in
Table 9. The rubber bag was connected to a vacuum suction system
and the evacuation was started. The reduced pressure was maintained
for about 10 minutes and the assembly was heated to the ultimate
temperature indicated in Table 9. After cooling, the laminated
glass was taken out and examined for air bubbles. The case in which
no air bubble was found was rate O and the case in which air
bubbles were observed was rated X.
9 TABLE 9 Deaeration characteristic (inclusion of air bubbles)
Initial temperature (.degree. C.) Ultimate temperature (.degree.
C.) 20 25 30 35 40 45 50 70 75 80 85 90 95 100 Example 28
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X X X X X .largecircle. .largecircle.
.largecircle. 29 .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X X X X X .largecircle.
.largecircle. Compar. Ex. 11 .largecircle. .largecircle.
.largecircle. .largecircle. X X X X X X X .largecircle.
.largecircle. .largecircle. 12 .largecircle. X X X X X X X
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. 13 .largecircle. .largecircle.
.largecircle. X X X X X X X .largecircle. .largecircle.
.largecircle. .largecircle. 14 .largecircle. .largecircle. X X X X
X X X .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. 15 .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. X X X X X X X
.largecircle. .largecircle.: No air bubble X: Air bubbles
[0362] according to Examples of the invention, the evacuation
initial temperature can be set high and the ultimate temperature
can be set low, so that an improved deaeration efficiency can be
obtained in preliminary contact bonding.
Industrial Applicability
[0363] Because the present invention is constituted as described
above, there is no moir phenomenon even when the arrangement and
pitch of the embossment are orderly so that there can be provided
an interlayer for a laminated glass with good workability in
cutting and laminating operations and excellent deaeration
characteristic in preliminary contact bonding.
[0364] Furthermore, because of the above constitution of the
invention, the trouble of premature marginal sealing does not take
place even if the deaeration initial temperature in preliminary
contact bonding is not critically controlled so that an interlayer
for a laminated glass with an excellent deaeration effect can be
provided. Moreover, since the self-adhesion of the interlayer can
be controlled, the interlayer has good handling
characteristics.
[0365] Because of the very constitution described above, the
invention provides an interlayer for a laminated glass which is not
only good in workability in terms of blocking resistance during
storage and handling in laminating work but also excellent in the
deaeration and sealing characteristics in preliminary contact
bonding. Therefore, particularly in the manufacture of large-area
or large-radius-of-curvature laminated glass or for increased
productivity of laminated glass production, both deaeration and
sealing between the glass and interlayer are sufficiently effected
so that the trouble of formation of air bubbles between the glass
and interlayer due to infiltration of pressurized air through the
sealing defect in the final contact bonding under heating and
pressure in an autoclave and the consequent incidence of rejects
can be largely obviated, thus laminated glass products with
particularly high transparency can be obtained.
[0366] As a further advantage of the interlayer for a laminated
glass according to the invention, satisfactory deaeration and
sealing can be obtained in preliminary contact bonding over a broad
temperature range so that the control of preliminary contact
bonding temperature is facilitated and the workability in
laminating work is remarkably improved, with the result that a
variety of processing requirements of various users can be
satisfied with ease and good efficiency.
[0367] Therefore, with the interlayer for a laminated glass
according to the invention, not only good workability is insured in
the manufacture of laminated glass products but there can be
obtained laminated glass of high quality substantially no incidence
of rejects due to formation of air bubbles even under stringently
restricted manufacturing conditions.
[0368] The laminated glass products manufactured by using the
interlayer for a laminated glass according to the invention is of
high quality almost free of the air bubble problem even when
manufactured under rigorously restricted conditions and can be used
with advantage in the glazing of the windows of cars, rolling
stock, aircraft, buildings and so forth.
* * * * *