Note: Descriptions are shown in the official language in which they were submitted.
CA 02549785 2000-07-07
IN'IEfZLAYER FbR LAMINATED GLASS AND LAMINATID GLASS
This application is a division of Canadian Patent Application Serial
No. 2376547, filed 03 July 2000, and which has been filed as a Canadian
National Phase Application corresponding to International Application No.
PCT/JP00/04383, filed 03 July 2000, and which was published on 11 January
2001 as International Publication No. WO 01/02316 Al.
TECIiNICAL FIELD
The present invention relates to an interlayer for a laminated glass
providing for inproved deaeration and a lamin.ated glass cornprising the
same.
BACKGROUND ART
The laminated glass manufactured by interposing an interlayer
conprising a sheet made of a the=plastic 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 autombiles,
aircraft, and buildings.
When such a laminated glass is subjected to an external impact, the
glass may break up but the interlayer sandwiched between the component
?0 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 inen in the vehicle or building are
protected against the injury by fragments of the broken glass.
Such a laminated glass is usually manufactured by interposing an
inter layer 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 remcval of the residual air entrapped
between the glass and the interlayer under suction, and finally carrying
out final contact bonding at elevated tenperature and pressure in an
autoclave.
The interlayer mentioned above is required to satisfy not only the
basic performaslce 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
CA 02549785 2007-01-29 (
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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.
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.
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."
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 "moire
phenomenon".
Furthermore, since the conventional embossment pattern
is generally provided in a random fashion by using sand blasted
roll, it hardly provides for sufficient deaeration.
The moire phenomenon mentioned above is not only
undesirable from appearance points of view but the
attention-distracting changeoftheinterferencefringescauses
an eye strain and motion sickness-like symptoms in the working
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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 ofa plurality ofinterlayersheetscauses
appearance of the moire phenomenon, thus detracting from
workability in a similar manner.
The moire 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, themoire phenomenon
occurs in most instances.
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 moire phenomenon.
To overcome this disadvantage of the abovemoire 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 f iner than
these protruded portions in a random pattern."
It is true that the above method contributes in a
considerable measure to attenuation oftheabovemoirephenomenon
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 becomesinsufficient
as a disadvantage.
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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 moire
phenomenon.
It is known, in the above technology, that the linear
designs displaced by 90 degrees for obviating the moire
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.
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.
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.
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 interlaver
CA 02549785 2007-01-29 /
particularly in termsofself -adhesivenessisadversely affected,
i.e. the self-adhesion of the interlayer is increased.
In fact, the above prior art interlayer has been fairly
improved in the tendency towardblocking during storage, handling
5 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.
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.
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.
Moreover, when a laminated glass is manufactured using
an interlayer such that both the geometry of embosses and the
levei 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.
In addition, in the case of the prior art interlayer, it
CA 02549785 2007-01-29 ~
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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,thisbeinginefficient
from productivity points of view.
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.
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 subj ected
to a negative pressure to bleed air from the margin of the
glass-interlayer assembly.
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 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 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.
When the vacuum deaeration metilod is adopted in the
CA 02549785 2007-01-29 ~
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preliminarv 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.
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 f inal contact bonding stage ( e. g. 13 0 C x 1. 3 MPa x 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.
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.
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
CA 02549785 2007-01-29 <
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by means of troughs is effective in preventing the premature
sealing in the course of deaeration.
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 C
to an ultimate temperature of 85 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 C to an ultimate temperature of 95 C so that even if the depth
(height) , width, and pitch of troughs or ridges are optimized,
i5 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
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 moire' 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 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
CA 02549785 2007-01-29 (
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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.
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 productivityintheprocessing of glass,
as well as deaeration and sealing properties at preliminary
contact bonding and which is capable of adapting itself with
ease andefficiently to varied processing needsofvarioususers,
and a laminated glass containing said interlayer.
The present invention is directed to an interlayer for
a laminated glass which comprises a thermoplastic resin sheet
provided with embossmentscomprising concave portions andconvex
portions on both sides thereof (hereinafter referredtosometimes
as "interlayer").
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.
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.
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 x 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.
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.
CA 02549785 2007-01-29 (
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
5 top.
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.
In the second aspect of the invention, a surface roughness
10 Ra of the plateau-forming top surface is preferably not less
than 2.5 pm, more preferably not less than 3.0 um.
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.
In the second aspect of the invention, the width of the
plateau-forming top surface may be constant or random.
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.
In the third aspect of the invention, a height of the
segmenting wall is preferably smaller than a depth of the trough.
In the third aspect of the invention, the segmenting walls
are preferably arranged at equal intervals.
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 >_ 0.25 on at least
one side.
In the fourth aspect of the invention, troughs may be
provided in a linear configuration or a grid configuration.
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
CA 02549785 2007-01-29
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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.
In the fifth 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.
In the fifth aspect of the invention, a depth of
segmenting troughs of the convex portion may be uniform or
random.
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 .
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.
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.
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.
In the present invention, the thermoplastic resin sheet
is preferably a plasticized polyvinyl acetal resin sheet.
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
CA 02549785 2007-01-29 r ,
lla
integral unit also constitutes one aspect of the invention.
In a further aspect, the present invention provides an
interlayer for a laminated glass which comprises a thermo-
plastic resin sheet provided with embossments comprising
concave portions and convex portions on both sides thereof,
and said concave portions being provided in a linear pattern,
a plateau-forming top surface of said convex portions having
fine concave and convex portions, as well as a pitch of
embossments on one side being different from a pitch of
embossments on the other side to thereby obviate an occurrence
of moire phenomenon.
In a still further aspect, the present invention provides
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,
and said concave portions on at least one side having a
trough-like geometry, and segmenting walls being formed in
said trough-like geometry to thereby obviating an occurrence of
a seal defect.
BRIEF DESCRIPTION OF THE DRAWINGS
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Fig. 1 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Examples 1 to 3.
Fig. 2 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Comparative Example 1.
Fig. 3 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Example 4.
Fig. 4 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Example S.
Fig. 5 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Example 6.
Fig. 6 is a schematic diagram illustrating the embossment
pattern of the interlayer for a laminated glass according to
Comparative Example 2.
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.
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.
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.
Fig.lOisaschematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 12 and 13.
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.
Fig.12isaschematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayer for a
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laminated glass which is obtained in Example 16.
Fig. 13 is a schematic diagramillustratingtheembossment
pattern (concave and convex patterns) of the interlayer for a
laminated glass which is obtained in Comparative Example 4.
Referring to Fig. 7 to Fig. 13, a represents the pitch
ofconvex portions,b represents the width ofthe plateau-forming
top surface of the convex portion, and c represents the width
of the concave portion.
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.
Fig.15isaschematic diagram illustrating the embossment
pattern (concave and convex patterns) of the interlayers for
laminated glass which are obtained in Examples 19 and 20.
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 S.
Fig. 17 is a perspective view showing a wedge-shaped tracer
(tip width 1000 m, opposite face angle 90 ) for use in Rzv
measurement.
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.
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.
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.
Fig. 20 shows an interlayer for a laminatedglass according
to the sixth aspect of the invention, where (a) is a plan view
and (b) is a side elevation view.
Referring to Fig. 20, 4 represents a cencave trough and
5 represents an embossment.
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DETAILED DESCRIPTION OF THE INVENTION
The present invention is now described in detail.
The interlayer of the invention comprises a thermoplastic
resin sheet.
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.
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.
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-ethylhex.oate, 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.
In the present invention, the addition level of such
CA 02549785 2007-01-29 ~
plasticizer is preferably within the range of 20 to 60 parts
by weight per 100 parts by weight of polyvinyl acetal resin.
Furthermore, where necessary, the interlayer according
to the invention may contain various additives such as heat
5 stabilizer, ultraviolet absorber, adhesion modulating agent,
and so forth.
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
10 particularly restricted but, just as it is the case with the
conventional interlayer, the preferred thickness is 0.2 to 2
mm.
For use as the interlayer according to the invention, said
thermoplastic resin sheet is provided with embossments
15 comprising concave portions and convex portions on both sides.
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.
The above convex portions may be equal or varying in height
and the corresponding concave portions may also be equal or
varying in depth.
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.
The technology of forming the embossment includes the
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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
auantitatively comprising constant and fine concave and convex
portions can be produced.
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 mi11 (mother
mill) and transf erring 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.
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
conf iguration, 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.
The di mens ions of the above convex po rt ion 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
CA 02549785 2007-01-29 ~
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is preferably 10 um to 1 cm, more preferably 50 to 1000 um,
particularly preferably 200 to 800 um. Within the range of 200
to 800 pm, a still greater improvement in clarity is obtained.
The height of the convex portion is preferably 5 to 500 um, more
preferably 20 to 100 um. Furthermore, the length of the bottom
of each convex portion is preferably 30 to 1000 um. 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.
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.
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.
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 moire phenomenon can be
effectively inhibited even if the arrangement and pitch of
embossments are comparatively orderly.
Generally speaking, appearance of the moire phenomenon
CA 02549785 2007-01-29 ~
18
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 sayby creating a dif ference 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 moire phenomenon even when the arrangement
and pitch of embosses on each side are comparatively orderly.
In the first aspect of the invention, it is preferable
that the concave portions on at least one side are continual.
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.
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 1.2S times
the pitch of embossments on the other side, the inhibitory effect
on appearance of the moire phenomenon tends to be insufficient.
The more preferred ratio is not less than 1.3 times.
Furthermore, in the first aspect of the invention, it is
preferable that the pitch (Li) 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 x 0.25)
of before and after a position of a convex portion on one side
is not more than S0% of the number of convex portions on one
side. When the convex portions satisfy the topological
CA 02549785 2007-01-29 ~
19
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
(Li x 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 moire 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 (Ll x 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.
Furthermore, in the f irst aspect of the present invention,
it is preferable that the concave portions on at least one side
are provided in a linear pattern.
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.
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
moire phenomenon does not take place even when the arrangement
CA 02549785 2007-01-29 !
and pitch of embosses are orderly, so that the workability in
cutting and laminating operations are improved.
Furthermore, when the embossment is such that the concave
portions on at least one side are continual, the concave portions
5 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.
10 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 x 0. 25) of before and after the position
15 of a convex portion on one side will be not more than 500 of
the number of convex portions on one side, the inhibitory effect
on the moire phenomenon is still further improved.
Furthermore, by embossing in such a manner that the pattern
of concave portions on at least one side will be a linear pattern,
20 the deaeration efficiency- improvingeffectisfurther enhanced.
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.
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 deaerationefficiency
can be realized.
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 relativel_v reduced
and, hence, said premature marginal sealing of the
CA 02549785 2007-01-29
21
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 um, more
preferably not greater than 701im.
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.
The above-mentioned convex portion preferably has fine
concave and convex portions on the plateau-forming top surface.
Flattening the top of the convex portionmay 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.
The surface roughness of said top surface is preferably
not less than Ra=2.5 }zm. When Ra is not less than 2.5 um, 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 um.
Fig. 7 is a schematic diagram showing the emboss pattern
(concave and convex patterns) of the interlayers obtained in
CA 02549785 2007-01-29
=.
22
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.
In the second aspect of the invention, said width (b) of
the plateau is preferably not less than 20 0 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%.
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.
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 moire phenomenon tends to
take place.
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.
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.
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 porti on are increased so that the premature
marginal seal ing oftheglass -interlayer assemblyin p:~eliminary
contact bonding is effectively inhibited. Therefore, the air
CA 02549785 2007-01-29 l
23
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%.
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.
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 necessityhelp to insure a positive seal between the interlayer
and the glass sheet, thus allowing milder sealing conditions
to be employed.
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
maybe cases in which deaeration and sealing will be insuf ficient .
The above segmentingwallsare 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.
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 moire phenomenon is liable
to take place.
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 >-
0.25 on at least one side.
CA 02549785 2007-01-29
24
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 um, vertex angle 90 ) 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 }im, opposite
face angle 90 ) shifted in a direction normal to the tip width
in accordance with JIS B 0601.
As used in this specification, the term "not on one and
the same level" means that the trough is not uniform in depth.
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.
Rzv, referred to above, is also generally measured with
a digital tracer-type electric surface roughness analyzer.
Stated differently, said Rzv is the 10-point average
roughness as measured with a wedge-shaped tracer (tip width 1000
pm) 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 pm in consideration of the
pitch of the convex portion and concave portion of the embossment
(which is usually 200 to 1000 um). By using a tracer having
a tip width of 1000 pm, the change in geometry of particularly
deep concave portions among the concave portions of the
embossments can be measured.
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
CA 02549785 2007-01-29 (
of the embossment in laminating work.
Intensive analysis of the relationship of the above Rzv
to Rz revealed that when the relationof Rzv/Rz >- 0. 25 is satisfied,
the deaeration and sealing performances in preliminary contact
5 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.
10 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 tolOO um
is employed and for such an interlayer, it is only necessary
to take into consideration a gravity of the order of about 500
15 to1000sheets. It has been found that the interlayer satisfying
the above-defined conditions shows satisfactory blocking
resistance under a loadof suchmagnitude andcanbe easilyhandled
in storage and laminating work.
In the fourth aspect of the invention, the preferred
20 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.
25 In the fourth aspect of the invention, the trough may be
provided in a linear configuration or in a grid configuration.
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.
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,
CA 02549785 2007-01-29
26
the volume of the concave and convex is decreased to facilitate
sealing particularly atthe marginalpartoftheglass- 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.
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 efficientlv in response to
varied processing needs of various users.
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.
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.
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.
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.
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,
CA 02549785 2007-01-29 (
27
sufficient deaeration can be achieved.
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 glassprocessing can beimproved
by control ling 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.
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 .
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 deaerationmethod 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
iscarried outunder heatand pressurein an autoclave. Therefore,
said angle is restricted to less than 25 , preferably less than
15 .
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 thev may be
randomly present, varying in depth, width, and/or pitch. The
sectionalconfiguration of the concave trough is not particulart-v
restrictedbut each troughmay for example be V-shaped, U-shaped,
CA 02549785 2007-01-29 ~
28
or bracket-shaped.
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 m,
more preferably 20 to 70 um. The width of the trough is preferably
20 to 100 um, 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.
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 effectmay be obtained, troughs are pref erably f ormed
on both sides.
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.
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.
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
,S
CA 02549785 2007-01-29
29
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.
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 passageway is arranged in a grid form, and deaeration
isperformed 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.
Furthermore, in the recent technology for laminated glass
production, i t 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.
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 multiroll 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.
The seventh aspect of the invention is concerned with an
interlayer for a laminated glass in which concave portion on
CA 02549785 2007-01-29 (
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.
5 In the seventh aspect of the inventi on, 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 50 of
the maximum trough depth, while the sectional area of the
10 trough-like geometry is kept constant. Therefore, in the
deaeration bythe vacuum deaeration technique, anef fective 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.
15 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
20 course of deaeration. The more preferred pitch is not more than
2 mm.
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"
25 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,
30 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.
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
CA 02549785 2007-01-29 ~
31
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.
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 pm, it can be used with success
when the deaeration is performedby the draw deaeration technique
as well.
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.
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 flatplate (pressedplate) 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 canbe 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.
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.
The glass sheet mentioned above is not particularly
restricted but includes inorganic glass sheets; andorganicglass
CA 02549785 2007-01-29
32
sheets such as the polycarbonate sheet, polymethyl methacrylate
sheet, and so forth.
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 multilayerstructure
of, for example, sheet glass/interlayer/sheet
glass/interlayer/sheet glass.
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.
When the laminated glass is to be manufactured using the
interlayermade of, forexample, a plasticized polyvinylbutyral
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.
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 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 C (vacuum deaeration
technique).
The assembly subjected to the preliminary contact bonding
CA 02549785 2007-01-29 ~
33
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 C under a pressure of 200 to 1500
kPa to give the laminated glass.
The laminated glass thus manufactured also constitutes
one aspect of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
The following examples illustrate the present invention
in further detail without defining the scope of the invention.
(Example 1)
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).
An engraving mill (mother mill ) having a linear embossment
design (concave and convex patterns)for embossing usewasforced
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 ~un.
An engraving mill(mother mill) having a linear embossment
design was forced against the surface of the other metal roll
of saidpair of embossing rolls and themetal roll and the engraving
mill were driven in association totransferthe embossment design
of the engraving mill to the metal roll. Then, the engraving
CA 02549785 2007-01-29
34
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 ~im.
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)
Except that the pitch of the embossment of one engraving
mill (mother mill) was changed to 300 ~.un and the pitch of the
embossment of the other engraving mill (mother mill) was changed
to 375 }.un, 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)
Except that the pitch of the embossments of one engraving
mill (mother mill) was changed to 300 lim and the pitch of the
embossments of the other engravingmill (mother mill)waschanged
to 430 um, 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.
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)
CA 02549785 2007-01-29 ~
Except that the pitch of the embossments was set to 300
lzm 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
5 on both sides with the same pitch of embossments for both sides.
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)
To 100 parts by weight of polyvinyl butyral resin (average
degree of polymerization 1700, residual acetyl group 1 mol %,
butyralization degree 6S mol %) was added 40 parts by weight
of the plasticizer triethylene glycol-di-2-ethylbutyrate (3GH),
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).
An engraving mill (mother mill) having a hemispherical
embossment design was forced against the surface of one of a
pair of inetal 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 pm.
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
CA 02549785 2007-01-29
36
the metal roll in steps of the unit embossment design to transfer
the embossment design of the engravingmill 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 ~un.
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)
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 um and that of the
other engraving mill to 300 um, the procedure of Example 4 was
otherwise repeated to manufacture an interlayerfor a laminated
glass having a linear embossment pattern onboth sides andvarying
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)
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 }zm and that of the other engraving
mill to 400 um, 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. S.
CA 02549785 2007-01-29
37
(Example 7)
Except that a linear embossment design with a pitch of
220 um was used for one of the engraving mills ( mother mills)
and the grid embossment design with a pitch of 320 pa 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)
Except that a linear embossment design with a pitch of
210 l,un 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.
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.
(Measurement of Rz)
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 pm,
vertex angle90degrees), the 1 0-point average surface roughness
{Rz (l.un) } of the embossment design on each side of the interlayer
was measured in accordance with JIS B0601.
(Measurement of Sm)
Under the microscope, the average pitch {Sm (~Lrn)} of
embosses on each side of the interlayer was measured.
Furthermore, with each of said 9 kinds of interlayers,
CA 02549785 2007-01-29
38
the appearance of the moire phenomenon was evaluated by the
following method. The results are shown in Table 1 and Table
2.
(Appearance of the moire phenomenon)
The interlayer was moved slowly and continuously and the
appearance of the moire phenomenon was visually monitored.
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.
(a) Draw deaeration
The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long x 30 cm wide x 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 C, 70 C or 80 C and passed
over a nip roll (air cylinder pressure 350 kPa, linear velocity
10 m/min) for preliminary contact bonding.
(b) Vacuum deaeration
The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long x 30 cm wide x 3 mm thick)
and the superf luous part was trimmed of f. 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 C, 80 C or 100 C, the pressure was returned
to atmospheric pressure to completepreliminary contact bonding.
The assembly subjected to preliminary contact bonding by
the above method (a) or (b) was held in an autoclave at a
temperature of 140 C and a pressure of 1.3 MPa for 10 minutes,
at the end of which time the temperature was lowered to 50 C
and the pressure was returned to atmospheric pressure to complete
CA 02549785 2007-01-29
39
the final contact bonding and provide a laminated glass.
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.
(Bake test of laminated glass)
The laminated glass was heated in an oven at 140 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.
0.~
Example 1 Example 2 Example 3 Compar. Ex, tr
Embossment design Linear Linear Linear Linear (D
F-
Embossment arrangement Orderly Orderly Orderly Orderly
Embossnient Face Average surface roughness : Rz ( u m) 36.2 43.2 44.5 40.6
of interlayer side Average pitch : Sm ( u m) 252.0 302.2 303.0 305.0
Reverse Average surface roughness : Rz (p m) 42.5 43.0 39.4 41.2
side Average pitch : Sm ( m) 324.0 372.5 431.2 305.0
Incidence of moir6 No No No Yes
0
Draw deaeration 60 70 80 60 70 80 60 70 80 60 70 80 r')
Prelirrlinary contact
bonding temperature (C)
Vacuum deaeration 60 80 100 60 80 100 60 80 100 60 80 100
N
0
O
F3alcc test of laminated glass Draw deaeration 0 1 0 2 0 0 0 1 0 0 2 0 o
(the number of sheets with air 10
bubbles/100 sheets) Vacuum deacration 1 0 0 0 0 0 1 0 1 1 0 0
~
Example 4 Example 5 Example 6 Example 7 Compar. Ex. 2 0-
Face side Hemispherical Linear Grid Linear Linear (D
Embossment design
Reverse side Hemispherical Linear Grid Grid Linear
Embossment arrangement Orderly Orderly Orderly Orderly Orderly
Embossment
of iriterlayer Average surface Face side 36.2 43.2 44.5 42.5 40.6
roughness : Rz Gc 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 (g m) Reverse side 310.0 302.5 421.2 320.2 210.2
Incidence of moirt No No No No Yes N
~
Draw 60 70 80 60 70 80 60 70 80 60 70 80 60 70 80
Preliminary contact deaeralion ~
bondirig temperature { C) Vacuum 60 80 100 60 80 100 60 80 100 60 80 100 60 80
100 0
deaeration 0.
0
Bake test of laminated glass dea~eration 0 1 0 2 0 0 0 1 0 0 1 1 0 2 0
(the number of sheets with air j
bubbles/100 sheets) Vacuum 1 0 0 0 0 0 1 0 1 2 0 0 1 0 0
deaeration
('.
CA 02549785 2007-01-29
42
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 moire 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.
In contrast, the interlayer f or a laminated glass according
to Comparative Example 1 as manufacturedusing apair of embossing
rolls fabricated from two engraving mills (mother mills) with
the same pitch of embossments (300 }im) 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
moire phenomenon. These results are indicative of poor
workability in cutting and laminating operations.
(Example 8)
As the thermoplastic resin sheet, "DXN film" (polyvinyl
butyral resin sheet, product of Sekisui Chemical) was used.
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 DXDfilm waspassed over this surface irregularity transfer
device to apply an embossed depression forming a trough design
with a continual bottomon one side of the DXN film. The transfer
conditions used were as follows.
Temperature of DXN film: room temperature
CA 02549785 2007-01-29 ~
43
Roll temperature: 130 C
Linear velocity: 10 m/min.
Press linear pressure: 500 kPa
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 }im,
the width of the plateau-forming top of the embossed convex
portion was 250 pm, and the width of the embossed concave portion
was 50 }zm.
(Example 9)
Except that the pitch of the embossed convex portions was
set to 300 um, the width of the plateau-forming top of the embossed
convex portion was set to 160 pm, and the width of the embossed
concave portion was set to 140 um, 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 bothsides.
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)
Except that the interval (pitch) of the embossed convex
portions was set to 200 um, the width of the plateau-forming
top of the embossed convex portion was set to 50 pm, the width
of the embossed concave portion was set to 150 pm, 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
CA 02549785 2007-01-29
44
continual at the bottom and embossed convex portions each having
a plateau-forming configuration on both sides.
(Example 11)
Except that the interval (pitch) of the embossed convex
portions was set to 500 um, the width of the plateau-forming
top of the embossed convex portion was set to 400 pm, the width
of the embossed concave portion was set to 100 ~im, 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.
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)
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
pm, 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.
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.
Using each of the above 5 kinds of interlayers, the
preliminary contact bonding by the vacuum deaeration method and
CA 02549785 2007-01-29 ~
the final contact bonding were serially carried out in the
following manner to construct 5 kinds of laminated glass
products.
(Vacuum deaeration)
5 The interlayer was sandwiched between two transparent
float glass sheets (30 cm long x 30 cm wide x 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
10 system and heated externally and held at a negative pressure
of -60 }kPa (absolute pressure 16 kPa) for 10 minutes . Theheating
was performed until the temperature of the assembly (preliminary
contact bonding temperature) had reached 70 C and the pressure
was then returned to atmosphericpressure to complete preliminary
15 contact bonding. The three different deaeration start
temperatures of 40 C, 50 C and 60 C were used at preliminary
contact bonding.
(Final contact bonding)
The glass assembly subjected to preliminary contact
20 bonding in the above manner was placed in an autoclave and held
at a temperature of 140 C and a pressure of 1300 kPa for 10 minutes.
The temperature was then lowered to 50 C and the pressure was
returned to atmospheric pressure to complete final contact
bonding and give a laminated glass.
25 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.
f- 3
Example 8 Example 9 Example 10 Example 11 Compar. Ex, 3
Embossment design Linear Linear Grid Grid Linear (p
Embossment arrangement (distribution) Orderly Orderly Orderly Orderly Orderly
Pitch of convex portions 300 300 200 500 200
(a: um)
Embossment Width of flat part of convex portions 250 160 50 400 -
(b : p m)
of interlayer Embossment
geometry b/a (%) 83.3 53.3 25.0 80.0 -
Width of concave portions (c : m) 50 140 150 100 200
Average surface roughness 42.5 40.5 45.2 41.2 60.2
N
( Rz: m)
Condtions of lnitial vacuum temperature ( C) 40 50 60 40 50 60 40 50 60 40 50
60 40 50 60 0
~
vacuum
Results of ~jeaeration Preliminary contact 70 70 70 70 70 70 70 70 70 70 70 70
70 70 70 o 0
evaluation bonding temperature ('C) 0
0
Bake test of laminated glass 0 0 1 0 1 5 1 5 10 1 0 1 10 50 90 0
(the number of sheets with air bubbles/100 sheets)
~
CA 02549785 2007-01-29
47
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 airbubbles (rej ects )
in the bake test invariably at the deaeration start temperatures
of 40 C, 50 C and 60 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 C),not a deliberatelyincreased preliminary contactbonding
temperature.
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 C or higher. This result indicates that unless the
deaeration start temperature in preliminary contact bonding is
strictly controlled to atleast below50 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)
(Preparation of the interlayer for a laminated glass)
For embossing, a variety ofembossing rollswere 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.
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
embossmentpattern on both sides. The transfer conditions used
CA 02549785 2007-01-29 ~
48
are as follows.
Temperature of DXN film: room temperature
Roll temperature: 130 C
Linear velocity: 10 m/min
Press linear pressure: 500 kPa
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.
Fig. 10 shows the embossment pattern (concave and convex
patterns) of the interlayers for laminated glass as obtained
inExample 12 andExample 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)
(Production of the interlayer for a laminated glass)
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.
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.
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:
3o 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
CA 02549785 2007-01-29
49
results are shown in Table 4.
(Measurement of Ra)
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 um, facial angle 90 ),
the 10-point average surface roughness {Ra (pm) } of the emboss
on each side of the interlayer for a laminated glass was measured
in accordance with JIS B 0601.
Moreover, using each of the above six kinds of interlayers
for laminated glass, preliminary contact bonding by the vacuum
deaeration technique andfinal contact bonding were carried out
serially as in Example 8 to manufacture six kinds of laminated
glass.
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.
H
Example Cornpar, Ex. a
t7' .
12 13 14 15 16 4
tu
Embossment design Linear Linear Linear Linear Linear Lirrear ,A
Embossment distribution Orderly, Orderly, Orderly, Orderly, Orderly, rotated
Orderly,
parallel parallel parallel parallel through 90 parallel
Pitch of main convex 300 500 300 500 200 200
portions (a : m)
Width of flat part of main 250 400 250 400 100 25
Embossment convex portions (b : N m)
of interlayer E,mbossmen b/a (%) 83 83 80 83 50 12.5
t ~
geometry Width of main concave 50 100 50 100 100 175
portions (c : u m)
N
Vt
Average surface roughness, 42.5 40.5 45.2 41.2 50.2 55.6 ~
m tracer (Rz : in) OD
Average surface roughness, 4.1 3.5 2.7 2.0 2.0 0.5 0
1000 u m Tracer (Ra : u m) Ln 0
Self-adhesive strengtti (g/15cm) 350 420 570 980 650 2540 C) o
0
Condtions Initial vacuum temperature 40 50 60 40 50 60 40 50 60 40 50 60 40 50
60 40 50 60
Results of of ('L)
evaluation vacuum Preliminary contact 70 70 70 70 70 70 70 70 70 70 70 70 70
70 70 70 70 70
deaeration bonding temperature ( 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)
CA 02549785 2007-01-29 ~
51
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 C, 50 C, and 60 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 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 pm 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.
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 -adhesivenessascomparedwith theinterlayerfor 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 ( rej ects ) owing to bubbling
in the bake test as compared with the Examples when the deaeration
start temperature in preliminary contact bonding was 50 C or
higher. This result indicates that unless the deaeration start
temperature for preliminary contact bonding is strictly
controlledto atleast be1ow50 C, theprematuremarginalsealing
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)
For producing various embossment patterns, a variety of
CA 02549785 2007-01-29 (
52
embossing rolls were prepared.
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 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.
As the thermoplastic resin sheet, "DXN film" (polyvinyl
butyral resin sheet, product of Sekisui Chemical) was used.
The above embossing roll was paired with a rubber roll
and with the embossing roll controlled at 130 C, the above
thermosetting resin sheet was passed over the roll set to apply
the predetermined emboss pattern.
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 S.
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 S.
CA 02549785 2007-01-29 i
53
Moreover, using each of the above 5 kinds of interlayers,
preliminary contact bonding by the vacuum deaeration techniaue
and final contact bonding were serially performed as described
below to manufacture 5 kinds of laminated glass sheets.
[Vacuum deaeration method]
The interlayer was sandwiched between two transparent
sheets of transparent float glass (30 cm long x 30 cm wide x
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 C and the preliminary contact
bonding temperature was set to one of the three levels, 60 C,
65 C, or 70 C.
(Final contact bonding)
The glass-interlayer assembly provisionally bonded by the
above procedure was placed in an autoclave and held at a
temperature of 140 C and a pressure of 1300 kPa for 10 minutes.
Then, the temperature was lowered to 50 C and the pressure was
returned to atmospheric pressure to complete final contact
bonding and thereby provide a laminated glass.
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 S.
Example Compar. Ex. ~3' .
17 18 19 20 5 (D
Embossment design Linear L.inear Grid Grid Linear cn
Embossment arrangement Orderly Orderly Orderly Orderly Orderly
Pitch of convex portions ( m) 350 500 350 500 350
Embossment Depth of concave portions ( u m) 50 50 50 50 50
of interlayer Embossment
geometry pitch of segmenting walls (1, m) 500 500 1000 1000 -
Height of segmenting walls (u m) 25 25 25 25 -
Average surface roughness (Rz: u m) 45.5 43.6 44.5 42.7 44.2
Condtions of Initial vacuum temperature (IC) 50 50 50 50 50 0
vacuum
Results of deaeration Preliminary contact 60 65 70 60 65 70 60 65 70 60 65 70
60 65 70
evaluation bonding temperature (C)
~
Bake test of laminated glass 5 4 1 2 2 1 4 3 2 5 3 2 30 15 5 Ln
(the number of sheets with air bubbles/100 sheets) A. 0
0
0
0
CA 02549785 2007-01-29
(Example 21)
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
5 concave troughs (linear) triangular in section and the
corresponding multiplicity of convex ridges (linear) . Further,
using glass beads the roll was blasted from a distance
of about 30 cm at an air pressure of 100 kPa to fabricate an
embossing roll.
10 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
15 modulator magnesium acetate,and using an extruder, theresulting
mixture was melt-kneaded and extruded from a die in a sheet form
to give a 0.76 mm-thick polyvinyl butyral sheet.
Using a pair of embossing rolls fabricated in the above
manner and the above polyvinyl butyral sheet, an interlayer was
20 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
25 troughs being not on the same level. The water content of this
interlayer was adjusted to 0.4 to 0.5 weight %.
(Example 22)
The surface of a metal roll was machined with an engraving
30 mill (pyramidcupmill) to formamultiplicityof concaveportions
each in the form of a quadrangular pyramid and the corresponding
multiplicity of convex portions. The roll was further blasted
with glass beads from a distance of about 30 cm at an air
pressure of 100 kPa to fabricate an embossing roll.
35 Except that a pair of embossing rolls fabricated as above
CA 02549785 2007-01-29
56
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)
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
from a distance of about 30 cm at an air pressure of 1 kg to
fabricate an embossing roll.
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 ofconvexridges
(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)
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.
CA 02549785 2007-01-29 ~
~
57
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.
For each of the interlayers obtained in the above Examples
andComparative 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 subj ected to the samebake test as inExample
1 to evaluate deaeration and sealing performances in the
preliminary contact bonding stage. The results are
collectively shown in Table 6.
[Measurement of Rzv]
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. um, opposite face angle 900) by scanning
with the tracer shifted in the direction normal to its tip width
in accordance with JIS B 0601.
[Evaluation of deaeration and sealing performances]
Preliminary contactbonding wasperformedbythefollowing
alternative techniques (draw deaeration and vacuum deaeration)
and final contact drawing was then performed to manufacture
laminated glass sheets.
(a) Draw deaeration method
The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long x 30 cm wide x 2 mm thick;
the margin of each glass sheet was curved by 1 mm with respect
CA 02549785 2007-01-29
58
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) hadreached60 C,70 C
or 80 C and, then, passed over a pair of nip rollers (air cylinder
pressure 350 kPa, linear velocity 10 m/min) for preliminary
contact bonding.
(b) Vacuum dearation
The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long x 30 cm wide x 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 C, 80 C or 100 C. Then, the pressure was returned
to atmospheric pressure to completepreliminary contactbonding.
The assemblies obtained by the above techniques (a) and
(b) were respectively held in an autoclave at a temperature of
140 C and a pressure of 1.3 MPa for 10 minutes, after which the
temperature was lowered to 50 C and the pressure returned to
atmospheric pressure forfinal contactbonding to give laminated
glass.
Example 21 Example 22 Example 23 Compar. Ex. 6
Configuration of convex portion Triangular Quadrangular Triangular Triangular
(D
(D Configuration of troughs Linear Grid Wavy Linear
tv
X, Arrangement Orderly Orderly Not orderly Orderly
Surface roughness of embossment, Rz ( m) 48.5 46.4 52.1 53.4
Surface roughness of negative model, Rzv ( m) 12.2 12.9 13.6 9.5
Rzv/Rz 0.252 0.278 0.261 0.178
Preliminary contact bonding temperature ( 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 CD
Qake test of laminated glass (the number of sheets Ln o
with air bubbles/100 sheets) ~ o
= 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
CA 02549785 2007-01-29
As the thermoplastic resin sheet, DX film (product of
Sekisui Chemical) was used.
Using a pair of rolls, namely a metal roll machined with
a triangular oblique line mill (75 mesh, 80 depth, manufactured
5 by Yuri Roll Co.) and a rubber roll having a JIS hardness of
45 to 7S, as the surface irregularity transfer device, the DX
film waspassed 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
10 were as follows.
Temperature of DX film: room temperature
Roll temperature: 140 C
Linear velocity: 10 m/min.
Press linear pressure: 2500 kPa
15 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
20 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. Thetransfer
conditions used here were as follows.
Temperature of DX film: room temperature
25 Roll temperature: 110 C
Linear velocity: 10 m/min.
Press linear pressure: 2000 kPa
Then, the other side of the DX film was subjected to the
same treatment as above to give an interlayer for a laminated
30 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)
35 Except that the transfer conditions for applying a
CA 02549785 2007-01-29
61
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.
Temperature of DX film: room temperature
Roll temperature: 120 C
Linear velocity: 10 m/min.
Press linear pressure: 2000 kPa
(Example 26)
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.
Condition (1)
Temperature of DX film: room temperature
Roll temperature: 120 C
Linear velocity: 10 m/min.
Press linear pressure: 2500 kPa
Condition (2)
Temperature of DX film: room temperature
Roll temperature: 130 C
Linear velocity: 10 m/min.
Press linear pressure: 2000 kPa
(Comparative Example 7)
CA 02549785 2007-01-29 t,
62
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.
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.
(1) Average surface roughness (Rz)
This parameter was measured in the same manner as in Example
1.
(2) Slip test
The interlayer cut to 50 cm x 50 cm was placed in horizontal
position on a smooth-surfaced glass plate (50 cm long x 50 cm
wide) and a slip glass sheet (10 cm long x 10 cm wide x 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 f rictional resistance was determined f rom 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 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.
(3) Antiblocking properties
Two sheets of the interlayer cut to 15 cm x 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
CA 02549785 2007-01-29
63
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.
(4) Bake test
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.
~
Example 24 Example 25 Example 26 Compar. Ex. 7 0'
Concave Geometry Grid of troughs Grid of troughs Grid of troughs Linear
troughs CD
Enibossment of portion Arrangement Orderly Orderly Orderly Orderly -_j
interlayer Convex Segmentation Segmented Segmented Segmented Not segmented
portion Depth of segmenting trough Shallow Slightly deep Deep -
Average surface roughness (Rz: u m) 38.2 42.2 46.1 56.5
Slip properties (max. frictional resistance : g) 265 255 225 302
Antiblocking properties (peel strength : g) 420 415 380 440
Performance
characteristics Preliminary contact Draw deaeration 60 70 80 60 70 80 60 70 80
60 70 80
0
of interlayer bonding temperature ( C) Vacuum deaeration 60 80 100 60 80 100
60 80 100 60 80 100 r')
Bake test
the number of sheets with Draw deaeration 2 1 0 4 1 0 6 2 0 20 10 0 CD
~
air bubbles/100 sheets Vacuum deaeration 1 0 0 2 1 0 4 3 0 25 15 0 0
rn ~
0
0
~
0
CA 02549785 2007-01-29
It will be apparent from Table 7 that the intelayers 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
5' in handing during storage and glass processing.
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
10 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.
In contrast, the laminated glass of Comparative Example
7 which was manufactured by using the interlayer for a laminated
15 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.
20 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)
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.
As shown in Fig. 20, the interlayer of the invention
comprises an extrusion-molded thermoplastic resin sheet
provided with a plurality of embossments comprising fine
concave portions and convex portions (not shown) on both sides
and concave troughs 4 on one side, said concave troughs 4 being
disposed generally in parallel with the direction of extrusion
CA 02549785 2007-01-29
66
X of the thermoplastic resin sheet.
(Production of an interlayer)
A thermoplastic resin sheet as obtained by extrusion of
plasticized polyvinyl butyral resin (product of Sekisui
Chemical; trade name "S-Rec Film DXN", 760 um thick) was passed
through asurfaceirregularity transfer device comprising a pair
of rolls, namely a metal roll formed with prismatic ridges
(height: 120 pm, base 150 um, pitch: 300 pm) complementary with
the concave troughs 4 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 4 each in a continuum parallel
to the extrusion direction of the sheet on one side thereof and
embossed concaveand convex patternson bothsides. Thetransfer
conditions used here were as follows.
Temperature of DX film: room temperature
Roll temperature: 120 C
Linear velocity: 10 m/min.
Press linear pressure: 500 kPa
(Comparative Example 8)
Except that the prismatic ridges of the metal roll were
disposed at an angle of 45 with the axial direction, theprocedure
of Example 27 was otherwise repeated to fabricate an interlayer.
(Comparative Example 9)
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)
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 27 was otherwise repeated
CA 02549785 2007-01-29 ~
67
to fabricate an interlayer.
The interlayers obtained in Example 27 and Comparative
Examples 8 to 10 were evaluated as follows.
(10-Point average surface roughness {Rz (I.un) } )
This parameter was measuredby the same method as in Example
1.
(Bake test)
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.
(a) Draw deaeration
The interlayer was sandwiched between two sheets of
transparent float glass (30 cm long x 30 cm wide x 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 C, 80 C or 90 C and, then, passed over
a nip roll (air cylinder pressure 35.5 MPa, linear velocity 10
m/min) for preliminary contact bonding.
(b) Vacuum deaeration
The interlayer was sandwiched between two sheets
transparent float glass (30 cm long x 30 cm wide x 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 C,80 C or90 C. The pressure wasthen returned to atmospheric
pressure to complete preliminary contact bonding.
Theglass- 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 C and a pressure
CA 02549785 2007-01-29 r
68
of 1. 3 MPa for 10 minutes, after which the temperature was lowered
to 50 C and the pressure returned to atmospheric pressure to
complete final contact bonding to give laminated glass.
The laminated glass sheets obtained as above were subj ected
to the bake test under the same conditions as in Example 1.
m
y
CrJ p1
x Example Compar. Ex,
27 8 9 10 (D
H I o0
(D 10-point average surface roughness (j,c m) 35.5 37.8 40,2 64.2
(D
70 C 1 4 3 14
Bake test Draw Temperature 809C 1 2 4 8
w deaeration
n
(D the number of 90 C 0 1 2 11
o sheets with air 700C 0 0 1 1
rfi bubbles/100
Vacuum
sheets deaeration Temperature 800C 0 1 0 2
~ 90qC 1 0 1 0 ~
r-r
w
CD
~
0 m O 0
0
O
J
O
IJ J
w
ci
(D
~.
rr
N=
n
~
r1'
0
CA 02549785 2007-01-29 ~
a surface roughness of about 60 pm, was coated with a lubricant
and a geometric transfer was made to the surface of a substrate
interlayer sheet at 100 C to give an interlayer having a random
emboss pattern with a surface roughness of 30 pm. The surface
5 of another metal roll was impressed with a triangular mill to
form 200 um-deep troughs on the surface of the metal roll and
further impressedwith a perpendicular triangular millto prepare
a roll surface reduced by 15 ~im in depth of the troughs
(corresponding to the bottom surface in the interlayer) . Then,
10 this roll surface was geometrically transferred to the surface
of the interlayer having said random embossment to give an
interlayer having 40 um-deep, 80 l.un-wide troughs at a pitch of
500 um within 55 um-deep, 60 um-wide troughs formed at a trough
pitch of 300 um.
(Example 29)
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 um as well as 50 pm-deep, 70 pm-wide troughs formed at
a pitch of 500 um within 55 }.un-deep, 60 pm-wide troughs.
(Comparative Example 11)
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 pm.
(Comparative Example 12)
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 pm.
CA 02549785 2007-01-29 ~
71
(Comparative Example 13)
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 um.
(Comparative Example 14)
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
lIm -
(Comparative Example 15)
The procedure of Example 28 was repeated to give an
interlayer having a random emboss pattern with a surface
roughness of 30 um. 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 having55um-deep,
60 pm-wide triangular wavy troughs at a pitch of 300 um.
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.
(Evaluation of deaeration characteristic)
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
CA 02549785 2007-01-29 ~
72
for air bubbles. The case in which no air bubble was found was
rate 0 and the case in which air bubbles were observed was rated
X.
a
w
Deaeration characteristic (inclusion of air bubbles)
Initial temperature M) Ultimate temperature (~) N
20 25 30 35 40 45 50 70 75 80 85 90 95 100
28 0 0 0 0 0 0 x x x x x 0 0 0
Example
29 0 0 0 0 0 0 x x x x x x 0 0
n 11 O O O O x x x x x x x O O O
(D
12 O x x x x x x x O O O O O O n
Cnmpar. Ex. 13 0 0 0 x x x x x x x 0 0 0 0 0 14 O o x x x x x x x p o 0 0 0 15
0 0 0 0 0 o x x x x x x x o co
0 No air bubble X Air bubbles o
H' J o
(D C'r N
Q0
rr
rt
rt
(D
N=
rr
(D
~
w
K
m
n
~
~
CA 02549785 2007-01-29 r
74
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
Because the presentinvention is constituted as described
above, there is no moire 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.
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.
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 andhandling inlaminating work butalsoexcellent
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
= CA 02549785 2007-01-29 ~
can be obtained.
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
5 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.
10 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
15 stringently restricted manufacturing conditions.
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
20 used with advantage in the glazing of the windows of cars, rolling
stock, aircraft, buildings and so forth.
