Note: Descriptions are shown in the official language in which they were submitted.
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OPTICAL FUNCTIONAL MATERIALS AND PROCESS FOR
PRODUCING THE SAME
BACKGROUND OF THE INVENTION
The present invention relates to an optical functional
film and more particularly to an optical functional film
suitable for use as an antireflection film in various
displays of word processors, computers, and television,
surfaces of polarizing plates used in liquid crystal
displays, optical lenses, such as sunglass lenses of
transparent plastics, lenses of eyeglasses, finder lenses
for cameras, covers for various instruments, and surfaces
of window glasses of automobiles and electric railcars, and
a process for producing the same.
Transparent substrates, such as glasses and plastics,
are used in curve mirrors, back mirrors, goggles, window
glasses, displays of personal computers and word
processors, and other various commercial displays. When
visual information, such as objects, letters, and figure,
is observed through these transparent substrates or, in the
case of mirrors, when an image from a reflecting layer is
observed through the transparent substrates, light reflects
at the surface of the transparent substrates, making it
difficult to see the visual information through the
transparent substrates.
Conventional methods for antireflection of light
include, for example, a method wherein an antireflection
coating is coated on the surface of glass or plastics, a
method wherein a very thin film of MgFz or the like having
a thickness of about 0.1 Nm or a metal deposited film is
provided on the surface of a transparent substrate, such as
glass, a method wherein an ionizing radiation curing resin
is coated on the surface of plastics, such as plastic
lenses, and a film of SiOz or MgFz is formed thereon by
vapor deposition, and a method wherein a coating having a
low refractive index is formed on a cured film of an
ionizing radiation curing resin.
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An about 0.1 um thin film of MgF2 formed on the above
glass will now be described in more detail. It is already
known that, when incident light perpendicularly enters a
thin film, in order for the antireflection film to prevent
the reflection of light by 100 and to pass light by 100%
therethrough, relationships represented by the equations
(1) and (2) should be met (see "Science Library" Physics =
9 "Optics," pp.70-72, 1980, Science Sha Ltd., Japan).
Equation (1)
nu=
Equation (2)
wherein ~,o represents a particular wavelength, no represents
the refractive index of the antireflection film at this
wavelength, h represents the thickness of the
antireflection film, and ng represents the refractive index
of the substrate.
It is already known that the refractive index ng of
glass is about 1.5, the refractive index naof an MgFz film
is 1.38 and the wavelength 7l0 of incident light is 5500
(reference). When these values are substituted in the
equation (2), the results of calculation show that the
thickness h of the antireflection film is about 0.1 um in
terms of the optimal thickness.
From the equation (1), it is apparent that prevention
of the reflection of light by 100 can be attained by the
selection of such a material that the refractive index of
the upper coating is approximately equal to a value of
square root of the refractive index of the lower coating.
The antireflection of light by utilizing the above
principle, i.e., by making the refractive index of the
upper coating slightly lower than the refractive index of
the lower coating, has hitherto been carried out in the
art.
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Further, the surface of displays has hitherto been
subjected to glare shielding treatment so that the
reflection of light from the exterior or interior of
displays could be diffused by the surface of the displays
to shield glare. The glare shielding treatment has been
carried out, for example, by a method wherein a resin
containing a filler, such as silicon dioxide, is coated on
the surface of a display, or a method wherein an antiglare
substrate with a resin containing a filler, such as silicon
dioxide, being coated thereon is applied onto the surface
of a display.
In particular, a filmy polarizing element, which
serves as an optical shutter, is provided on the surface of
displays, such as liquid crystal displays. Since, however,
the polarizing element per se has a poor hard property, it
is protected by a transparent protective substrate, such as
glass, a transparent plastic sheet, or a transparent
plastic film, to form a polarizing plate. However, the
transparent protective substrate of a plastic, such as a
transparent plastic sheet or a transparent plastic film, is
also likely to be scratched. In order to solve this
problem, in recent years, a polarizing plate with a hard
property being imparted to the surface thereof has .been
developed. For example, Japanese Patent Laid-Open No.
105738/1989 describes such a technique.
This publication discloses a transparent protective
substrate having a hard property and an antiglare property,
that is, a triacetate film for light control, which is
laminated to a polarizing element to constitute a
polarizing plate. Since this triacetate film is formed by
providing a cured coating of an ultraviolet curing epoxy
acrylate resin on one surface of an unsaponified triacetate
film, it has an excellent hard property.
In order to further impart an antiglare property to
the above triacetate film having an excellent hard
property, a resin composition comprising the above
ultraviolet curing epoxy acrylate resin and, added thereto,
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amorphous silica is coated on the surface of a triacetate
film followed by curing. In laminating the coated
triacetate film onto a polarising element to form a
polarizing plate, the coated triacetate film is first
saponified with an alkali for the purpose of enhancing the
adhesion to a polarizing element and, at the same time,
antistatic purposes and then laminated to a polarizing
element to form a polarizing plate.
However, it is noted that, when a layer for imparting
a light antireflection property and, at the same time, an
antiglare property is provided on a substrate film to form
an antiglare-antireflection film, at least layers having
these functions and other various layers, such as an
adhesive layer, are provided, necessitating the provision
of at least one layer, for example, between a substrate
film and the outermost layer provided on the substrate
film. In this case, the reflection of light occurs in the
interface of layers, particularly in the interface of a
layer having a relatively large thickness of not less than
0.5 um such as formed by coating, i.e., a larger thickness
than the wavelength of light, deteriorating the
antireflection effect of the antireflection film.
On the other hand, for the conventional antireflection
film with an antireflection layer being formed on the
outermost surface of a transparent substrate film, since
the thickness of the antireflection layer is as small as
about 0.1 pm, the antireflection film has a poor hard
property and, at the same time, is likely to be scratched.
Further, for the film having an optical function, such
as an antireflection film, optical functional membranes are
usually laminated thereon. These optical functional
membranes have an unsatisfactory gas barrier property and,
hence, have a poor moistureproofness. In particular, a
polarizing element used in a liquid crystal display has
poor moistureproofness, and, therefore, moistureproofness
should be imparted thereto.
Accordingly, the first object of the present invention
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is to provide, with respect to optical functional materials
constituting optical materials, such as an antireflection
film and an antireflection film, an optical functional film
having excellent gas barrier properties, such as
moistureproofness.
The second object of the present invention is to
provide an antiglare-antireflection film having an
antiglare property and/or an antireflection property and,
at the same time, capable of reducing the reflection of
light in the interface of layers in the interior of the
film and a process for producing the same.
The third object of the present invention is to
provide an antireflection film having a hard property in
addition to properties involved in the second object and a
process for producing the same.
DISCLOSURE OF THE INVENTION
In order to attain the first object, the optical
functional film of the present invention comprises an SiOx
film, wherein x is 1.50 s x S 4.00, of which the surface
has a contact angle with water of 40 to 180°. The SiOx
film is preferably formed by the plasma CVD process.
Further, in the present invention, the SiOx film preferably
has a coefficient of dynamic friction of not more than 1.
The optical functional film may be typically prepared
by forming an SiOx film, wherein x is 1.50 S x S 4.00,
directly or through other layer(s), on a transparent
substrate film preferably by the plasma CVD process. It,
however, can be formed on various optical articles at their
desired positions.
In order to attain the second object, the antiglare-
antireflection film of the present invention comprises: (1)
a transparent substrate film and, provided on said
transparent substrate film directly or through other
layer( s ) , an antiglare layer, having a fine uneven surface,
composed mainly of a binder resin, ( 2 ) a layer having a low
refractive index, provided on said antiglare layer, which
is lower than the refractive index of said antiglare layer,
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(3) the refractive index of said antiglare layer being
higher than that of a layer (for example, a transparent
substrate film, a primer layer, an adhesive layer, or a
second hard coat layer) in contact with said antiglare
layer on its surface remote from said layer having a low
refractive index.
In order to attain the third object, the antiglare-
antireflection film of the present invention comprises: (1)
a transparent substrate film and, provided on said
transparent substrate film directly or through other
layer(s), an antiglare layer having a fine uneven surface
and a hard property, (2) a layer having a low refractive
index, provided on said antiglare layer, which is lower
than the refractive index of said antiglare layer, (3) the
refractive index of said antiglare layer being higher than
that of a layer in contact with said antiglare layer on its
surface remote from said layer having a low refractive
index.
The process for producing an antiglare-antireflection
film according to the present invention comprises the steps
of: (1) coating a resin composition comprising a binder
resin and fine particles having a high refractive index,
which is higher than the refractive index of said binder
resin, on a transparent substrate film directly or through
other layer(s), the refractive index of said resin
composition being higher than that of a layer in direct
contact with the underside of a layer using said resin
composition in a layer construction of an antiglare-
antireflection film as a final product; (2) laminating a
matte embossing film having a fine uneven surface onto the
resultant coating so that the fine uneven surface faces the
coating; (3) subjecting said laminate to heat treatment
and/or irradiation with ionizing radiation to cure the
coating; (4) peeling off said embossing film from said
laminated having a cured coating to form an antiglare layer
having a fine uneven surface; and (5) forming on said
antiglare layer formed in said step (4) a layer having a
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low refractive index which is lower than the refractive
index of said antiglare layer.
Another process for producing an antiglare
antireflection film according to the present invention
comprises the steps of: (1) coating a resin composition
comprising a binder resin and fine particles having a high
refractive index, which is higher than the refractive index
of said binder resin, on a matte embossing film having a
fine uneven surface, the refractive index of said resin
composition being higher than that of a layer in direct
contact with the underside of a layer using said resin
composition in a layer construction of an antiglare-
antireflection film as a final product; ( 2 ) laminating said
embossing film having a coating formed in said step (1),
directly or through other layer(s), onto a transparent
substrate film so that said coating faces said transparent
substrate film; (3) subjecting said laminate to heat
treatment and/or irradiation with ionizing radiation to
cure the coating; (4) peeling off said embossing film from
said laminated having a cured coating to form an antiglare
layer having a fine uneven surface; and ( 5 ) forming on said
antiglare layer formed in said step (4) a layer having a
low refractive index which is lower than the refractive
index of said antiglare layer.
A further process for producing an antiglare-
antireflection film according to the present invention
comprises the steps of: (1) coating a resin composition
comprising a binder resin and fine particles having a high
refractive index, which is higher than the refractive index
of said binder resin, on a matte embossing film having a
fine uneven surface, the refractive index of said resin
composition being higher than that of a layer in direct
contact with the underside of a layer using said resin
composition in a layer construction of an antiglare-
antireflection film as a final product; (2) curing the
resultant coating to form a hard coat layer having a high
refractive index; (3) laminating said embossing film with
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a hard coat layer having a high refractive index being
formed thereon in said step ( 2 ) , through an adhesive layer,
onto at least one surface of a transparent substrate film
so that said hard coat layer having a high refractive index
faces said transparent substrate film; (4) curing said
adhesive layer and peeling off said embossing film from the
laminate to transfer said hard coat layer having a fine
uneven surface and a high refractive index to said
transparent substrate film; and (5) forming on said hard
coat layer having a high refractive index a layer having a
low refractive index which is lower than the refractive
index of said hard coat layer having a high refractive
index.
The antireflection film according to a further aspect
of the present invention comprises:
( 1 ) a transparent substrate film and, provided through
other layers) on at least one surface of said transparent
substrate film, a layer having a low refractive index as a
surface layer;
(2) at least one layer of said other layers) being a
hard coat layer composed mainly of a binder resin, said
hard coat layer being in direct contact with said layer
having a low refractive index; and
( 3 ) the refractive index of said hard coat layer being
higher than that of a layer in contact with said hard coat
layer on its surface remote from said layer having a low
refractive index.
The process for producing an antireflection film
according to a further aspect of the present invention
comprises the steps of:
(1) coating a resin composition comprising a binder
resin and fine particles having a high refractive index,
which is higher than the refractive index of said binder
resin, on at least one surface of a transparent substrate
film directly or through other layer(s), the refractive
index of said resin composition being higher than that of
a layer in direct contact with the underside of a layer
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using said resin composition in a layer construction of an
antireflection film as a final product;
(2) curing the resultant coating to form a hard coat
layer having a high refractive index; and
(3) forming on said hard coat layer having a high
refractive index a layer having a low refractive index
which is lower than the refractive index of said hard coat
layer having a high refractive index.
The process for producing an antireflection film
according to a further aspect of the present invention
comprises the steps of:
(1) coating a resin composition comprising a binder
resin and fine particles having a high refractive index,
which is higher than the refractive index of said binder
resin, on a release film having a smooth surface, the
refractive index of said resin composition being higher
than that of a layer in direct contact with the underside
of a layer using said resin composition in a layer
construction of an antireflection film as a final product;
(2) laminating said release film with a coating being
formed thereon in said step (1), directly or through other
layer(s), onto at least one surface of a transparent
substrate film so that said coating faces said transparent
substrate film;
(3) subjecting said laminate to heat treatment and/or
irradiation with ionizing radiation to cure the coating;
(4) peeling off said release film from said laminate
having a cured coating to transfer said hard coat layer
having a high refractive index to the side of said
transparent substrate film; and
(5) forming on said hard coat layer having a high
refractive index a layer having a low refractive index
which is lower than the refractive index of the refractive
index of said hard coat layer having a high refractive
index.
The process for producing an antireflection film
according to a further aspect of the present invention
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comprises the steps of:
(1) coating a resin composition comprising a binder
resin and fine particles having a high refractive index,
which is higher than the refractive index of said binder
resin, on a release film having a smooth surface, the
refractive index of said resin composition being higher
than that of a layer in direct contact with the underside
of a layer using said resin composition in a layer
construction of an antireflection film as a final product;
(2) curing said coating to form a hard coat layer
having a high refractive index;
(3) laminating said release film with a hard coat
layer having a high refractive index being formed thereon
in said step (2), through an adhesive layer, onto at least
one surface of a transparent substrate film so that said
hard coat layer having a high refractive index faces said
transparent substrate film;
(4) curing said adhesive layer and then peeling off
said release film from said laminate to transfer said hard
coat layer having a high refractive index to the side of
said transparent substrate film; and
(5) forming on said hard coat layer having a high
refractive index a layer having a low refractive index
which is lower than the refractive index of said hard coat
layer having a high refractive index.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a diagram showing a laminate film comprising
a triacetyl cellulose film having a refractive index of
1.49 and, formed thereon, a vapor-deposited SiOx film
having a refractive index of 1.46;
Fig. 2 is a diagram showing a laminate film comprising
a TAC substrate film having a refractive index of 1.49 and,
formed thereon in the following order, a hard coat layer
having a refractive index of 1.49 and a vapor-deposited
SiOx film having a refractive index of 1.46;
Fig. 3 is a diagram showing a laminate film comprising
a triacetyl cellulose film having a refractive index of
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1.49 and, formed thereon in the following order, a hard
coat layer having a refractive index of 1.55 and a vapor-
deposited SiOx film having a refractive index of 1.46;
Fig. 4 is a diagram showing a laminate film comprising
a saponified triacetyl cellulose film having a refractive
index of 1.49 and, provided thereon in the following order,
a primer layer having a refractive index of 1.55, a hard
coat layer, having a refractive index of 1.65, comprising
a resin with fine particles of Zn0 having a high refractive
index being dispersed therein, and a vapor-deposited SiOx
film having a refractive index of 1.46;
Fig. 5 is a diagram showing a spectral reflectance
curve for a laminate film shown in Fig. 1;
Fig. 6 is a diagram showing a spectral reflectance
curve for a laminate film shown in Fig. 2;
Fig. 7 is a diagram showing a spectral reflectance
curve for a laminate film shown in Fig. 3;
Fig. 8 is a diagram showing a spectral reflectance
curve indicating that the wave pitch increases with
decreasing the film thickness;
Fig. 9 is a diagram showing a spectral reflectance
curve for the same laminate film as shown in Fig. 3 except
that the refractive index of the hard coat layer has been
increased to 1.65;
Fig. 10 is a diagram showing a spectral reflectance
curve for a laminate film shown in Fig. 4;
Fig. 11 is a diagram showing a comparison of a
spectral reflectance curve for a laminate film having a
layer construction of TAC substrate film (refractive index
1.49)/hard coat layer having a high refractive index
(refractive index 1.62)/layer having a low refractive index
(refractive index 1.46) with those for other laminate
films;
Fig. 12A is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example A1;
Fig. 12B is a cross-sectional view showing a layer
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construction of an antireflection film prepared in Example
B1;
Fig. 13A is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example A2;
Fig. 13B is a cross-sectional view showing a layer
construction of an antireflection film prepared in Example
B2;
Fig. 14A is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example A3;
Fig. 14B is a cross-sectional view showing a layer
construction of a polarizing plate with the antiglare
antireflection film of the present invention being
laminated thereto;
Fig. 15A is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example A4;
Fig. 15B is a view showing a layer construction of a
liquid crystal display using a polarizing plate with the
antireflection film of the present invention being
laminated thereto;
Fig. 16 is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example, A5;
Fig. 17 is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example A8;
Fig. 18 is a cross-sectional view showing a layer
construction of an antiglare-antireflection film prepared
in Example A9;
Fig. 19 is a diagram showing a layer construction of
a polarizing plate with the antiglare-antireflection film
of the present invention being laminated thereto;
Fig. 20 is a diagram showing a layer construction of
a liquid crystal display using a polarizing plate with the
antiglare--antireflection film of the present invention
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being laminated thereto;
Fig. 21 is a conceptual diagram showing the reflection
of light; and
Fig. 22 is a conceptual diagram showing the
transmission of light.
BEST MODE FOR CARRYING OUT THE INVENTION
Constituent features of the present invention will now
be described in more detail with reference to the following
preferred embodiments.
Antiglare-antireflection Properties
The term "antiglare" used herein is intended to mean
such a phenomenon that a fine uneven surface of an
antiglare layer formed on the surface of a display or the
like or a matte material disposed within the antiglare
layer diffuses light from the exterior of the display or
the like to cause diffuse reflection, reducing the
projection of a fluorescent lamp or the like onto an image
plane. The above antiglare layer has a drawback that light
transmitted through a display is unfavorably diffused to
lower the resolution and contrast.
On the other hand, the term "antireflection" used
herein is intended to means such a phenomenon that the
reflection energy of external light is lowered by
interference to somewhat reduce the projection of external
light and increase the amount of light transmitted through
a display ( due to a reduction in reflection ) , enhancing the
resolution and contrast. Fig. 21 shows a conceptual
diagram showing the reflection of light, and Fig. 22 a
conceptual diagram showing the transmission of light.
The term "antiglare-antireflection" used herein is
intended to mean that the antiglare property compensates
for drawbacks of the antireflection property and vice
verse, improving regular reflection of light, diffuse
reflection, projection of external light, contrast, and the
like. In particular, in the case of a film having an
antiglare property, light transmitted from the back gives
rise to diffuse reflection, and the use of such a film in
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a display unfavorably darkens a surface image. By
contrast, the antiglare-antireflection film of the present
invention has a feature that the reflection is reduced and,
at the same time, the transmittance is markedly increased,
thereby providing a bright image, an enhanced contrast, and
a good visibility. The above antiglare, antireflection,
and antiglare-antireflection properties will be compared
with one another in the following Table 1.
Table 1
Item Anti- Anti- Antiglare-
glare reflec- antireflec-
tion tion
Re ular reflection Small Small Small
Diffuse reflection Lar Small Small
a
Projection of external Small Somewhat Small
li ht
Amount of regular Small Large Somewhat
transmitted li ht small
Amount of diffuse Large Small Somewhat
transmitted li ht lar a
Amount of transmitted
light (amount of regular
transmitted light + Small Large Somewhat
amount of diffuse large
transmitted li ht)
Resolution Low High Somewhat
hi h
Contrast Low High Hi h
From Table l, it is apparent that optical properties
required of displays are substantially satisfied by
imparting an antiglare-antireflection property. The
optical properties required of displays are that the
regular reflection on the surface thereof is small, the
projection of external light is small, the amount of
transmitted light is large enough to p=ovide a bright
image, and the amount of regular transmitted light is large
enough to provide excellent resolution and contrast.
Transparent Substrate Film
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Examples of the transparent substrate film include a
triacetyl cellulose film, a diacetyl cellulose film, a
cellulose acetate butyrate film, a polyether sulfone film,
a polyacrylic resin film, a polyurethane resin film, a
~ polyester film, a polycarbonate film, a polysulfone film,
a polyether film, a trimethylpentane film, a polyether
ketone film, and a (meth)acrylonitrile film. Among them,
a triacetyl cellulose film and a uniaxial stretched
polyester film are particularly favorable because they have
excellent transparency and no optical anisotropy. The
thickness of the transparent substrate film is, in general,
preferably in the range of from about 8 to 1000 Nm.
Antiglare Layer
The antiglare layer of the present invention has a
fine uneven surf ace . Such a fine uneven surf ace can be
formed, for example, by a method wherein embossing is
carried out using a matte embossing film having a fine
uneven surface, a method wherein a coating is formed using
an antiglare coating solution prepared by adding a matte
material, such as plastic beads, to a binder resin, or a
method wherein a combination of surface embossing with the
addition of a matte material is used. When the surface of
the antiglare layer is finely embossed without use of any
matte material in order to impart an antiglare property
(that is, a property by which light emitted from the
interior is diffused to prevent glaring), an advantageous
effect can be attained that the transparency of the
resultant antiglare-antireflection film is not particularly
lowered.
Embossing films used in the formation of a fine uneven
surface by embossing include a plastic film, such as
releasable PET, the surface of which has been made uneven
as desired, and a plastic film, such as PET, with a fine
uneven layer being formed thereon. The embossing film may
be laminated onto a coating of a resin, for example, a
coating of an ultraviolet curing resin followed by
irradiation with ultraviolet radiation to cure the coating.
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In this case, if the embossing film is a film comprising
PET as a substrate, the ultraviolet radiation at its short
wavelengths is absorbed in the film, making the curing of
the ultraviolet curing resin unsatisfactory. For this
reason, when an embossing film is applied to a coating of
an ultraviolet curing resin, the embossing film should be
such that the transmittance in an ultraviolet region of
wavelengths 254-300 nm is not less than 20~.
Preferred examples of the matte material used in the
formation of a fine uneven surface by adding a matte
material to a resin include plastic beads which have a high
transparency and a refractive index close to the matrix
resin. The selection of a matte material having a
refractive index as close as possible to that of the resin
enables the antiglare property to be increased without
detriment to the transparency of the coating. Examples of
the plastic beads as the matte material include acryl
beads, polycarbonate beads, polystyrene beads, and vinyl
chloride beads. The particle diameter of these plastic
beads is suitably in the range of from 1 to 10 um.
When the above matte material is added, it is likely
to settle in the resin composition. Inorganic fillers,
such as silica, may be added for prevention of settling.
The larger the amount of the inorganic filler added, the
better the effect of preventing settling of the matte
material. However, the addition of the inorganic filler
has an adverse effect on the transparency of the coating.
For this reason, it is preferred to incorporate into the
resin an inorganic filler having a particle diameter of not
more than 0.5 um in such an amount as will not be
detrimental to the transparency of the coating but useful
for the prevention of settling, i.e., less than about 0.1$
by weight. This silica is different from a silica having
a particle diameter of about 5 pm commonly used as the
conventional matte material in that the particle diameter
is very small. The addition thereof is not useful for
imparting an antiglare property. Further, the particular
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silica used in the present invention is different from the
conventional matte material also in that the conventional
matte material is added in an amount of 1 to 30~ by weight,
whereas in the present invention the particular silica is
used in a very small amount of not more than 0.1$ by
weight. When the present invention is carried out without
use of any inorganic filler as a nonsettling suspending
agent for preventing settling of the matte material, the
matte material settles in the coating solution, making it
necessary to bring the coating solution to a homogeneous
state by sufficient stirring prior to use of the coating
solution.
The binder resin used in the antiglare layer may be
any resin (for example, a thermoplastic resin, a
thermosetting resin, or an ionizing radiation curing resin)
so far as it is transparent. In order to impart a hard
property to the antiglare layer so that the final
antiglare-antireflection film can have an excellent hard
property, the thickness of the antiglare layer is not less
than 0.5 pm, preferably not less than 3 um. The thickness
falling within the above range enables the hardness to be
maintained and can impart a hard property to the antiglare-
antireflection film.
In the present invention, "having a hard property" or
"hard coat" refers to a coating having a hardness of not
less than H as measured by a pencil hardness test specified
in JIS K5400.
In order to further improve the hardness of the
antiglare layer, it is preferred to use, as a binder resin
in the antiglare layer, a reaction curing resin, that is,
a thermosetting resin and/or an ionizing radiation curing
resin. Examples of the thermosetting resin include a
phenolic resin, a urea resin, a diallyl phthalate resin, a
melamine resin, a guanamine resin, an unsaturated polyester
resin, a polyurethane resin, an epoxy resin, an aminoalkyd
resin, a melamine-urea copolycondensed resin, a silicone
resin, and a polysiloxane resin. If necessary, curing
CA 02280473 1999-09-O1
- 18 -
agents, such as crosslinking agents and polymerization
initiators, polymerization accelerators, solvents,
viscosity modifiers, and the like may be added to these
resins.
The ionizing radiation curing resin is preferably one
having an acrylate functional group, and examples thereof
include a polyester resin, a polyether resin, an acrylic
resin, an epoxy resin, a urethane resin, an alkyd resin, a
spiroacetal resin, a polybutadiene resin, and a polythiol-
polyene resin having a relatively low molecular weight, an
oligomer or a prepolymer of a ( meth ) acrylate or the like of
a polyfunctional compound, such as a polyhydric alcohol,
and those containing a relatively large amount of a
reactive diluent, such as a monofunctional monomer, such as
ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene,
methylstyrene, or N-vinylpyrrolidone, and a polyfunctional
monomer, for example, trimethylolpropane tri(meth)acrylate,
hexanediol (meth)acrylate, tripropylene glycol
di(meth)acrylate, diethylene glycol di(meth)acrylate,
pentaerythritol tri(meth)acrylate, dipentaerythritol
hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, or
neopentyl glycol di(meth)acrylate.
Among them, a mixture of a polyester acrylate with
polyurethane acrylate is particularly preferred. The
reason for this is as follows. The polyester acrylate
provides a coating having a very high hardness and is,
therefore, suitable for the formation of a hard coat.
Since, however, a coating consisting of polyester acrylate
alone has low impact resistance and is fragile, the
polyurethane acrylate is used in combination with the
polyester acrylate to impart the impact resistance and
flexibility to the coating. The proportion of the
polyurethane acrylate incorporated is not more than 30
parts by weight based on 100 parts by weight of the
polyester acrylate. This is because the incorporation of
the polyurethane acrylate in an amount exceeding the above
upper limit 30 parts by weight makes the coating so
CA 02280473 1999-09-O1
- 19 -
flexible that the hard property is lost.
In order to bring the above ionizing radiation curing
resin composition to W curing type, it is preferred to
incorporate, into the ionizing radiation curing resin
composition, a photopolymerization initiator, such as an
acetophenone compound, a benzophenone compound, Michler's
benzoylbenzoate, an a-amyloxime ester, tetramethyl thiuram
monosulfide, or a thioxanthone compound, and a
photosensitizer, such as n-butylamine, triethylamine, or
tri-n-butylphosphine. In the present invention, it is
particularly preferred to incorporate urethane acrylate or
the like as an oligomer and dipentaerythritol
hexa(meth)acrylate or the like as a monomer.
A solvent type resin may be incorporated in an amount
of 10 to 100 parts by weight based on 100 parts by weight
of the ionizing radiation curing resin. A thermoplastic
resin is mainly used as the solvent type resin. The
solvent type thermoplastic resin added to the ionizing
radiation curing resin may be any conventional resin used
in the art. In particular, when a blend of a polyester
acrylate with a polyurethane acrylate is used as the
ionizing radiation curing resin, the use of polymethyl
methacrylate acrylate or polybutyl methacrylate acrylate as
the solvent type resin enables the hardness of the coating
to be kept high. Further, this is advantageous also from
the viewpoint of transparency, particularly, low haze
value, high transmittance, and compatibility, because since
the refractive index of the polymethyl methacrylate
acrylate or polybutyl methacrylate acrylate is close to
that of the main ionizing radiation curing resin, the
transparency of the coating is not lost.
When cellulosic resins, particularly such as triacetyl
cellulose, are used as the transparent substrate film, the
use of cellulosic resins, such as nitrocellulose, acetyl
cellulose, cellulose acetate propionate, and
ethylhydroxyethyl cellulose, is advantageous as a solvent
type resin incorporated into the ionizing radiation curing
CA 02280473 1999-09-O1
- 20 -
resin from the viewpoint of adhesion of coating and
transparency.
The reason for this is as follows. When toluene is
used as a solvent in combination with the above cellulosic
resin, the adhesion between the transparent substrate film
and the coating resin can be improved in the coating of a
coating solution containing the solvent type resin onto the
transparent substrate film, despite fact that triacetyl
cellulose as the transparent substrate film is insoluble in
toluene. Further, since toluene does not dissolve
triacetyl cellulose as the transparent substrate film, the
surface of the transparent substrate film is not whitened,
enabling the transparency to be maintained.
The antiglare layer may be formed by coating or
transfer. In the coating method, an antiglare layer can be
formed by coating the above resin composition for an
antiglare layer directly or through other layers) onto a
transparent substrate film, for example, by gravure reverse
coating or the like. On the other hand, in the transfer
method, an antiglare layer can be formed by coating the
above resin composition for an antiglare layer onto an
embossing film having a fine uneven surface, for example,
by gravure reverse coating or the like, laminating the
coated embossing film directly or through other layers)
onto at least one surface of a transparent substrate film
so that the coating faces the transparent substrate film,
subjecting the laminate to heat treatment and/or ionizing
radiation irradiation treatment to cure the coating, and
peeling off the embossing film from the laminate to form an
antiglare layer. Alternatively, the antiglare layer may be
formed by, before the above lamination, subjecting the
coating on the embossing film to heat treatment and/or
ionizing radiation irradiation treatment to cure the
coating, laminating the embossing film having a cured
coating through an adhesive layer onto at least one surface
of the transparent substrate film, and peeling off the
embossing film from the laminate to form an antiglare
CA 02280473 1999-09-O1
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layer.
Since the antiglare layer according to the present
invention is formed by coating, the thickness thereof, as
described above, is not less than 0.5 Nm which is larger
than a film formed by the vapor growth process (for
example, vacuum deposition, sputtering, ion plating, or
plasma CVD ) , enabling a hard property to be imparted to the
resultant antiglare-antireflection film.
The refractive index of the antiglare layer may be
enhanced by a method wherein a binder resin having a high
refractive index is used, a method wherein fine particles
having a high refractive index, which is higher than the
refractive index of the binder resin used in the antiglare
layer, are added to a binder resin, or a method wherein the
above two methods are used in combination.
Binder resins having a high refractive index include
(1) resins containing an aromatic ring, (2) resins
containing halogen atoms except for F, for example, Br, I,
and C1, and (3) resins containing atoms, such as S, N, and
P atoms. Resins meeting at least one of these requirements
are preferred because they have a high refractive index.
Examples of the resin (1) include styrol resins, such as
polystyrene, polyethylene terephthalate, polyvinyl
carbazole, polycarbonate prepared from bisphenol A.
Examples of the resin (2) include polyvinyl chloride
and polytetrabromobisphenol A glycidyl ether. Examples of
the resin (3) include polybisphenol S glycidyl ether and
polyvinylpyridine.
Examples of the fine particles having a high
refractive index include Zn0 (refractive index: 1.90), TiOz
( refractive index: 2. 3-2 . 7 ) , CeOz ( refractive index: 1. 95 ) ,
Sbz05 ( refractive index: 1. 71 ) , Sn02, ITO ( refractive index:
1. 95 ) , Y203 ( refractive index: 1. 87 ) , La203 ( refractive
index: 1.95), Zr02 (refractive index: 2.05), and A1z03
(refractive index: 1.63). Among these fine particles
having a high refractive index, ZnO, TiOz, CeOz, and the
like are preferably used because UV shielding effect can be
CA 02280473 1999-09-O1
- 22 -
additionally imparted to the antiglare-antireflection film
of the present invention. Further, the use of antimony-
doped SnOz or ITO is preferred because" electronic
conduction is improved, attaining the effect of preventing
the deposition of dust by virtue of antistatic effect, or
electromagnetic wave shielding effect when the antiglare-
antireflection film of the present invention is used in
CRT. In order to make the antiglare layer transparent, it
is preferred for the particle diameter of fine particles
having a high refractive index to be not more than 400 nm.
In the antiglare layer, when an ionizing radiation
curing resin is used as the binder resin, the ionizing
radiation curing resin may be cured by the conventional
curing method usually employed for curing ionizing
radiation curing resins, that is, applying an electron beam
or ultraviolet light. For example, in the case of curing
with an electron beam, use may be made of an electron beam
or the like having an energy of 50 to 1000 KeV, preferably
100 to 300 Kev, emitted from various electron beam
accelerators, such as a Cockcroft-Walton (type)
accelerator, a van de Graaff accelerator, a resonance
transformer accelerator, an insulation core transformer
accelerator, a linear accelerator, a dynatron accelerator,
and a high frequency accelerator. On the other hand, in
the case of curing with W, use may be made of ultraviolet
light or the like emitted from an ultrahigh pressure
mercury lamp, a high pressure mercury lamp, a low pressure
mercury lamp, a carbon arc, a xenon arc, a metal halide
lamp, and the like.
Layer Having Low Refractive Index
A layer having a low refractive index is formed in
contact with the above antiglare layer or a hard coat layer
which will be described later. The refractive index nL of
the layer having a low refractive index is, of course,
lower than the refractive index nH of the antiglare layer
(or hard coat layer). In this case, the approach of the
refractive index nL of the layer having a low refractive
CA 02280473 1999-09-O1
- 23 -
index to a requirement represented by following equation
(3) improves the antireflection effect. Therefore, the
approach to the requirement represented by the equation ( 3 )
is preferred.
n = n Equation (3)
The material having a low refractive index used in the
formation of the layer having a low refractive index may be
any material so far as it can meet a requirement
represented by the equation (3). However, inorganic
materials can be favorably used because they have high
hardness and can form a film by the vapor phase growth
process. Examples of the inorganic material for forming a
layer having a low refractive index include LiF ( refractive
index : 1. 4 ) , MgF2 ( refractive index: 1. 4 ) , 3NaF ~ A1F3
(refractive index: 1.4), A1F3 (refractive index: 1.4),
Na3A1F6 (cryolite, refractive index: 1.33), SiOx (x:
1.50Sxs4.00, preferably 1.70Sxs2.20)(refractive index:
1.35-1.48), and NaMgF3 (refractive index: 1.36).
When the layer having a low refractive index is formed
on an antiglare layer having a fine uneven surface, it is
preferably formed so as to avoid such a phenomenon that the
material for a layer having a low refractive index
concentrates in recessed portions of the fine uneven
surface of the antiglare layer, causing the resultant the
layer having a low refractive index on its surface to
become flat. In order to avoid this unfavorable
phenomenon; the layer having a low refractive index is
formed by a gas phase growth process, for example, vacuum
deposition, sputtering, reaction sputtering, ion plating,
and plasma CVD. The formation of an SiOx film, wherein x
is 1.50 S x S 4.00, by the plasma CVD process is particularly
preferred because the resultant film has good hardness and
surface properties and an excellent adhesion to the resin
layer and the process can reduce heat damage to the
transparent plastic substrate film as compared with the
CA 02280473 1999-09-O1
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case where other vapor growth processes are used. The SiOx
will now be described in more detail.
The organic material having a low refractive index is
preferably an organic substrate, such as a polymer with a
fluorine atom being introduced thereinto because the
refractive index is low and not more than 1.45.
Polyvinylidene fluoride (refractive index n = 1.40) can be
mentioned as a resin usable with a solvent because it is
easy to handle. When polyvinylidene fluoride is used as
the organic material having a low refractive index, the
refractive index of the layer having a low refractive index
becomes about 1.40. It is also possible to add an acrylate
having a low refractive index, such as trifluoroethyl
acrylate (refractive index n = 1.32), in an amount of 10 to
300 parts by weight, preferably 100 to 200 parts by weight,
for the purpose of further lowering the refractive index of
the layer having a low refractive index.
It is noted that the trifluoroethyl acrylate is of
monofunctional type and, therefore, the strength of the
layer having a low refractive index is not satisfactory.
For this reason, it is preferred to further add a
polyfunctional acrylate, for example, dipentaerythritol
hexacrylate (abbreviation: DPHA, tetrafunctional type);
which is an ionizing radiation curing resin. The larger
the amount of DPHA added, the higher the strength of the
layer. However, the lower the amount of DPHA added, the
lower the refractive index of the layer having a low
refractive index. For this reason, it is recommended that
the amount of DPHA added be 1 to 50 parts by weight,
preferably 5 to 20 parts by weight.
The layer having a low refractive index can be
prepared, for example, by forming a film in a single layer
or a plurality layers using an inorganic material having a
low refractive index on a hard coat layer having a high
refractive index by a vapor growth process (vacuum
deposition, sputtering, reactive sputtering, ion plating,
plasma CVD, or the like), or alternatively by coating a
CA 02280473 1999-09-O1
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resin composition, having a low refractive index,
containing an inorganic material having a low refractive
index or an organic material having a low refractive index
to form a coating in a single layer or a plurality of
layers.
Optical Functional Membrane
The SiOx film, wherein x is 1.50SxS4.00, is not
limited to the use in the layer having a low refractive
index and can be widely used as an optical functional
membrane.
In particular, an SiOx film formed by the CVD process,
preferably plasma CVD process, has a higher density and a
higher gas barrier property as compared with the
conventional vacuum-deposited film. In addition, it has
excellent properties suitable as an optical functional
membrane. In particular, since the above SiOx film has
excellent moistureproofness, when an antireflection film
having an SiOx film formed by the plasma CVD process is
used with the antireflection film being laminated to a
polarizing element, the SiOx film can advantageously serve
to prevent the access of moisture to the polarizing element
which is known as having poor resistance to moisture.
Experimental data substantiating the superiority of
the SiOx film formed by the plasma CVD process are given in
the following Table 2. Films used for the moistureproof
experiment were a triacetyl cellulose film (indicated as
"TAC"), a triacetyl cellulose film with a 7 dam-thick hard
coat resin coating being formed thereon [indicated as "HC
(7 um)/TAC"], a triacetyl cellulose film with a 1 um-thick
vinylidene fluoride coating being formed thereon [indicated
as "K coat: vinylidene fluoride (1 um)/TAC"], and a
triacetyl cellulose film with a 1000 ~-thick plasma CVD
film of SiOx being formed thereon [indicated as "SiOx
(1000 ~)/TAC"]. These films were subjected to measurement
of moisture permeability per day under conditions of a
humidity of 90$ and a temperature of 40°C according to a
moistureproofness test specified in JIS (Z0208).
CA 02280473 1999-09-O1
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Table 2
Layer construction Moisture permeabil_i_ty
( the yer on tFie~t side per aye
bein the to la er)
TAC 600 /mZ
HC ( 7 m ) /TAC~ 300 /m2
K coat: vinylidene 20 g/mz
fluoride (1 m)/TAC
Si0 (10001~)/TAC Not more than 5 /mz
From Table 2, it is apparent that SiOx(1000 H)/TAC has
the lowest moisture permeability, i.e., excellent
moistureproofness. Although vinylidene fluoride (lum)/TAC
has somewhat good moistureproofness, it cannot be suitably
used as an optical material because the coating is soft and
yellows with time.
When the plasma CVD film is used with a polarizing
element or other layers containing a dye or the like, the
gas barrier property of the plasma CVD film can prevent the
deterioration of the dye or the like. The SiOx film formed
by the plasma CVD process has a high density and, hence,
can be a scratch-resistant film.
As compared with the conventional vacuum-deposited
film, the plasma CVD process can relatively easily vary the
x value of the SiOx film. Further, the x value of the
conventional vacuum-deposited film is less than 2, whereas
in the case of the plasma CVD process, the x value can
exceed 2. This enables the SiOx film formed by the plasma
CVD process to have a lower refractive index than the
conventional vacuum-deposited film, offering an advantage
that the resultant film has a high transparency. Further,
the plasma CVD film is superior to the conventional vacuum-
deposited film in adhesion to the substrate.
Difference in properties between the SiOx film formed
by the vacuum deposition process and the SiOx film formed
by the plasma CVD process is shown in the following Table
3.
CA 02280473 1999-09-O1
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Table 3
Vacuum de osition Plasma CVD
Density Low High
(Particles collide (After deposition on
with one another to substrate, the
cause adhesion of deposit becomes an
SiOx mass to form a SiOx film)
film)
O content X<2 X>2 is also
possible.
The oxygen content
is higher than that
for vapor deposition
Gas barrier Low High
ro ert
Transparency Likely to cause Transparent
color change
( ellowin )
Refractive High Low
index
Coefficient High Low
of friction
In the present invention, the silicon oxide film as an
optical functional membrane preferably comprises an SiOx
film, wherein x is 1.50 s x S 4.00, of which the surface
has a contact angle with water of 40 to 180°, preferably
not less than 70°, particularly preferably not less than
100°. According to the finding by the present inventor,
when the contact angle is not less than 40°, the
antifouling is improved, rendering the film suitable for
use as an optical functional membrane.
The coefficient of dynamic friction of the SiOx film
is preferably not more than 1, still preferably not more
than 0.5. In this case, the coefficient of dynamic
friction is a value as measured by a method specified in
JIS-K7125. As the coefficient of dynamic friction
decreases, particularly when it is not more than 1, the
slidability of the surface of the membrane is likely to
increase, favorably increasing the scratch resistance or
CA 02280473 1999-09-O1
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fracture resistance of the surface of the film.
The SiOx film, as described above, is preferably
formed by the CVD process, preferably plasma CVD process.
The term "plasma CVD" used herein is intended to mean,
among CVD's, a conventional process using plasma. For
plasma CVD, in general, heat energy is used together with
electric energy. Specifically, in plasma CVD, a starting
gas for a contemplated silicon oxide film creates plasma in
a CVD device by discharging, realizing non-equilibrium
conditions under which a film forming reaction is allowed
to proceed.
In the present invention, the formation of the SiOx
film by the plasma CVD under the following conditions are
particularly preferred from the viewpoint of forming a
silicon oxide film which is excellent in both optical
properties and surface properties.
(a) An organosiloxane is used as a starting gas.
(b) Plasma a.s formed from a starting gas by
discharging.
(c) CVD is carried out in the absence of an inorganic
vapor deposition source.
(d) The substrate film, on which the SiOx film is to
be vapor-deposited, is maintained at a relatively low
temperature.
(e) Film forming conditions are such that an
organosiloxane remaining undecomposed is present in the
resultant SiOx film.
Silanes or siloxanes commonly called "organosilicon"
may be properly used as the organosiloxane which serves as
the starting gas. Specific examples of the organosiloxane
include methyltrimethoxysilane, dimethyldiethoxysilane,
tetraethoxysilane, vinyltriethoxysilane, 3-
methacryloxypropyl trimethoxysilane, vinyl-tris(2-
methoxyethoxy)silane, tetramethoxysilane,
trimethylethoxysilane, vinyltriacetoxysilane,
ethyltriethoxysilane, tetrakis(2-ethylhexoxy)silane,
vinyltrimethoxysilane, tetrakis(2-methoxyethoxy)silane,
CA 02280473 1999-09-O1
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m a t h y 1 p h a n y 1 d i m a t h o x y s i 1 a n a ,
tetrakis(methoxyethoxyethoxy)silane, tetramethylsilane,
dimethyldimethoxysilane, n-propyltrimethoxysilane,
tetrakis(2-ethylbutoxy)silane, n-octyltriethoxysilane,
a c a t o x y p r o p y 1 t r i m a t h o x y s i 1 a n a ,
t r i s ( t r i m a t h y 1 s i l o x y ) p h a n y 1 s i 1 a n a ,
octamethylcyclotetrasiloxane, hexamethyldisiloxane,
o c t a m a t h y 1 t r i s i 1 o x a n a , 1 , 2 , 3 , 3 -
tetrakis(trimethylsiloxy)disiloxane, and
pentamethyldisiloxane. They may be used alone or in the
form of a mixture of two or more.
Further, in the present invention, it is preferred not
to use a solid inorganic silicon compound as the deposition
source. Furthermore, in the present invention, the CVD
process is carried out preferably under such film forming
conditions that a starting gas (organosiloxane) remaining
undecomposed is present in the resultant SiOX film.
Specifically, an SiOx film, which is excellent in both
optical properties and surface properties, can be formed
when the starting gas is not completely decomposed and the
organosiloxane remaining undecomposed is included or
incorporated in the resultant silicon oxide film. The
above film forming conditions are particularly advantageous
from the viewpoint of increasing the contact angle of the
surface of the film and regulating the coefficient of
dynamic friction to a small value range.
In the formation of an SiOx film by the plasma CVD
process, it is generally considered that organosiloxane
activated by plasma collides with a substrate, and the
organosiloxane adsorbed on the surface of the substrate is
reacted with activated organosiloxane from a gas phase and
oxygen to remove an organic group containing carbon,
thereby growing an SiOx film while forming a matrix of Si-
O-Si. In this case, it is considered that when the plasma
energy is low or the concentration of active oxygen in
plasma is low, the organosiloxane on the surface of the
substrate is not completely decomposed to leave the organic
CA 02280473 1999-09-O1
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group, leaving a group like silicone rubber or silicone
grease on the surface (and partly within the substrate) to
develop such a property that the water repellency or the
coefficient of friction is reduced.
However, when the decomposition of the organosiloxane
is incomplete and the oxidation number of Si is small, the
refractive index of the formed film becomes large,
rendering the SiOx film unpractical as a layer having a low
refractive index of the antireflection film. On the other
hand, when the organosiloxane is completely decomposed to
completely consume the organic group on the surface of the
resultant film, the refractive index becomes low. In this
case, however, the surface of the resultant film becomes
hydrophilic, which is likely to cause dirt to deposit on
the surface of the film and, at the same time, makes it
difficult to remove the deposited dirt. Further, the
coefficient of friction too becomes large, inducing defects
such as scratch. These renders the resultant film
unpractical as a surface layer of the antireflection film.
For this reason, care should be taken to control the film
forming conditions.
For reference, properties of films formed by various
processes are listed below.
CA 02280473 1999-09-O1
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Sample Contact Coefficient Refrac- Starting
angoe of friction tive material
( ). index
(Film formation by vacuum
deposition)
SiOz/HC/TAC 32 1.50 1.44 SiOZ
(Film formation by batch plasma CVD)
SiOx/HC/TAC(1) 50 1.10 1.42 HMDSO+OZ
SiOx/HC/TAC(2) 104 0.44 1.44 HMDSO+OZ
SiOx/HC/TAC(3) 155 0.40 1.60 HMDSO+Oz
(Film formation by continuous CVD)
plasma
SiOx/HC/TAC(1) 55 0.45 1.42 HMDSO+O~
SiOx/HC/TAC(2) 102 0.47 1.44 HMDSO+Oz
SiOx/HC/TAC(3) 152 0.40 1.50 HMDSO+Oz
(Film formation by continuous CVD followed
plasma by
corona treatment of film on its
the surface)
SiOx/HC/TAC 59 0.92 1.44 HMDSO+O2
(Film formation by batch plasma CVD)
SiOx/HC/TAC 43.9 1.13 1.44 SiH4
(Film formation by vacuum
deposition)
SiOx/HC/TAC 11.2 1.12 1.50 Si0
SiOx/HC/TAC 12.3 1.89 1.50 Si0
Saponified TAC 19 - -
In the above table, the abbreviated layer or compound
identifications have the following meanings:
HC: hard coat layer
TAC: triacetyl cellulose film
HMDSO: hexamethyldisiloxane
SiOx/HC/TAC: layer construction wherein HC and SiOx layer
are formed in that order on TAC layer
Additional Layers
In the antireflection film of the present invention,
layers for imparting various functions may be further
provided in addition to the above layers. For example, in
order to improve the adhesion between the transparent
substrate film and the hard coat layer or for other
CA 02280473 1999-09-O1
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purposes, it is possible to provide a primer layer or an
adhesive layer on the transparent substrate film. Further,
in order to improve the hard property or antiglare
property, the hard coat layer and the antiglare layer may
be separately provided, or alternatively these layers may
be provided respectively in a plurality of layers.
The refractive index of the additional layers provided
between the transparent substrate film and the antiglare
layer is preferably intermediate between the refractive
index of the transparent substrate film and the refractive
index of the antiglare layer.
The additional layers provided between the transparent
substrate film and the antiglare layer, as described above,
may be formed directly or indirectly on the transparent
substrate film by coating. When a hard coat layer is
formed on a transparent substrate film by transfer, it is
also possible to use a method wherein a contemplated
additional layer is formed by coating on a hard coat layer
which has been previously formed on an embossing film (or
alternatively on an embossing film having a fine uneven
surface) and then transferred to a transparent substrate
film.
An adhesive or a pressure sensitive adhesive may be
applied on the underside of the antiglare-antireflection
film, and, for use, the resultant coated antireflection
film may be applied onto the surface of an object from
which reflection should be prevented.
Hard Coat Layer
The binder resin usable in the hard coat layer may be
any resin (for example, a thermoplastic resin, a
thermosetting resin, or an ionizing radiation curing resin)
so far as it is transparent. In order to impart a hard
property to the antireflection film, the thickness of the
antireflection layer is not less than 0.5 um, preferably
not less than 3 um. The thickness falling within the above
range enables the hardness to be maintained and can impart
a hard property to the antireflection film.
CA 02280473 1999-09-O1
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In the present invention, "having a hard property" or
"hard coat" refers to a coating having a hardness of not
less than H as measured by a pencil hardness test specified
in JIS K5400.
In order to further improve the hardness of the hard
coat layer, it is preferred to use, as a binder resin in
the hard coat layer, a reaction curing resin, that is, a
thermosetting resin and/or an ionizing radiation curing
resin. Examples of the thermosetting resin include a
phenolic resin, a urea resin, a diallyl phthalate resin, a
melamine resin, a guanamine resin, an unsaturated polyester
resin, a polyurethane resin, an epoxy resin, an aminoalkyd
resin, a melamine-urea copolycondensed resin, a silicone
resin, and a polysiloxane resin. If necessary, curing
agents, such as crosslinking agents and polymerization
initiators, polymerization accelerators, solvents,
viscosity modifiers, and the like may be added to these
resins.
The ionizing radiation curing resin is preferably one
having an acrylate functional group, and examples thereof
include a polyester resin, a polyether resin, an acrylic
resin, an epoxy resin, a urethane resin, an alkyd resin, a
spiroacetal resin, a polybutadiene resin, and a polythiol
polyene resin having a relatively low molecular weight, an
oligomer or a prepolymer of a ( meth )acrylate or the like of
a polyfunctional compound, such as a polyhydric alcohol,
and those containing a relatively large amount of a
reactive diluent, such as a monofunctional monomer, such as
ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene,
methylstyrene, or N-vinylpyrrolidone, and a polyfunctional
monomer, for example, trimethylolpropane tri(meth)acrylate,
hexanediol (meth)acrylate, tripropylene glycol
di(meth)acrylate, diethylene glycol di(meth)acrylate,
pentaerythritol tri(meth)acrylate, dipentaerythritol
hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, or
neopentyl glycol di(meth)acrylate.
Among them, a mixture of a polyester acrylate with
CA 02280473 1999-09-O1
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polyurethane acrylate is particularly preferred. The
reason for this is as follows. The polyester acrylate
provides a coating having a very high hardness and is,
therefore, suitable for the formation of a hard coat.
Since, however, a coating consisting of polyester acrylate
alone has low impact resistance and is fragile, the
polyurethane acrylate is used in combination with the
polyester acrylate to impart the impact resistance and
flexibility to the coating. The proportion of the
polyurethane acrylate incorporated is not more than 30
parts by weight based on 100 parts by weight of the
polyester acrylate. This is because the incorporation of
the polyurethane acrylate in an amount exceeding the above
upper limit 30 parts by weight makes the coating so
flexible that the hard property is lost.
In order to bring the above ionizing radiation curing
resin composition to UV curing type, it is preferred to
incorporate, into the ionizing radiation curing resin
composition, a photopolymerization initiator, such as an
acetophenone compound, a benzophenone compound, Michler's
benzoylbenzoate, an a-amyloxime ester, tetramethyl thiuram
monosulfide, or a thioxanthone compound, and a
photosensitizer, such as n-butylamine, triethylamine, or
tri-n-butylphosphine. In the present invention, it is
particularly preferred to incorporate urethane acrylate or
the like as an oligomer and dipentaerythritol
hexa(meth)acrylate or the like as a monomer.
A solvent type resin may be incorporated in an amount
of 10 to 100 parts by weight based on 100 parts by weight
of the ionizing radiation curing resin. A thermoplastic
resin is mainly used as the solvent type resin. The
solvent type thermoplastic resin added to the ionizing
radiation curing resin may be any conventional resin used
in the art. In particular, when a blend of a polyester
acrylate with a polyurethane acrylate is used as the
ionizing radiation curing resin, the use of polymethyl
methacrylate acrylate or polybutyl methacrylate acrylate as
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the solvent type resin enables the hardness of the coating
to be kept high. Further, this is advantageous also from
the viewpoint of transparency, particularly, low haze
value, high transmittance, and compatibility, because since
the refractive index of the polymethyl methacrylate
acrylate or polybutyl methacrylate acrylate is close to
that of the main ionizing radiation curing resin, the
transparency of the coating is not lost.
When cellulosic resins, particularly such as triacetyl
cellulose, are used as the transparent substrate film, the
use of cellulosic resins, such as nitrocellulose, acetyl
cellulose, cellulose acetate propionate, and
ethylhydroxyethyl cellulose, is advantageous as a solvent
type resin incorporated into the ionizing radiation curing
resin from the viewpoint of adhesion of coating and
transparency.
The reason for this is as follows. When toluene is
used as a solvent in combination with the above cellulosic
resin, the adhesion between the transparent substrate film
and the coating resin can be improved in the coating of a
coating solution containing the solvent type resin onto the
transparent substrate film, despite the fact that triacetyl
cellulose as the transparent substrate film is insoluble in
toluene. Further, since toluene does not dissolve
triacetyl cellulose as the transparent substrate film, the
surface of the transparent substrate film is not whitened,.
enabling the transparency to be maintained.
The hard coat layer may be formed by coating or
transfer. In the coating method, a hard coat layer can be
formed by coating the above resin composition for a hard
coat layer directly or through other layers) onto a
transparent substrate film, for example, by gravure reverse
coating or the like. On the other hand, in the transfer
method, a hard coat layer can be formed by coating the
above resin composition for a hard coat layer onto a
release film having a smooth surface, for example, by
gravure reverse coating or the like, laminating the above
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coated release film directly or through other layer( s ) onto
at least one surface of a transparent substrate film so
that the coating faces the transparent substrate film,
subjecting the laminate to heat treatment and/or ionizing
radiation irradiation treatment to cure the coating, and
peeling off the release film from the laminate to form a
hard coat layer. Alternatively, the hard coat layer may be
formed by, before the above lamination, subjecting the
coating on the release film to heat treatment and/or
ionizing radiation irradiation treatment to cure the
coating, laminating the release film having a cured coating
prepared in the above step through an adhesive layer onto
at least one surface of the transparent substrate film in
such a manner that the coating on the release film faces
the transparent substrate, and peeling off the release film
from the laminate to form a hard coat layer.
Since the hard coat layer according to the present
invention is formed by coating, the thickness thereof is
not less than 0.5 pm which is larger than a film formed by
the vapor growth process (for example, vacuum deposition,
sputtering, ion plating, or plasma CVD), enabling a hard
property to be imparted to the resultant antireflection
film.
The refractive index of the hard coat layer may be
enhanced by a method wherein a binder resin having a high
refractive index is used, a method wherein fine particles
having a high refractive index, which is higher than the
refractive index of the binder resin used in the hard coat
layer, are added to a binder resin, or a method wherein the
above two methods are used in combination.
Binder resins having a high refractive index include
(1) resins containing an aromatic ring, (2) resins
containing halogen atoms except for F, for example, Br, I,
and C1, and (3) resins containing atoms, such as S, N, and
P atoms. Resins meeting at least one of these requirements
are preferred because they have a high refractive index.
Examples of the resin (1) include styrol resins, such as
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polystyrene, polyethylene terephthalate, polyvinyl
carbazole, polycarbonate prepared from bisphenol A.
Examples of the resin (2) include polyvinyl chloride and
polytetrabromobisphenol A glycidyl ether. Examples of the
resin (3) include polybisphenol S glycidyl ether and
polyvinylpyridine.
Examples of the fine particles having a high
refractive index include Zn0 ( refractive index: 1. 90 ) , Ti02
( refractive index: 2 . 3-2 . 7 ) , CeOz ( refractive index: 1. 95 ) ,
Sbz05 ( refractive index: 1. 71 ) , SnOZ, ITO ( refractive index:
1. 95 ) , Y203 ( refractive index: 1. 87 ) , La203 ( refractive
index: 1.95), Zr02 (refractive index: 2.05), and A1203
(refractive index: 1.63). Among these fine particles
having a high refractive index, ZnO, TiOz, CeOz, and the
like are preferably used because W shielding effect can be
additionally imparted to the antireflection film of the
present invention. Further, the use of antimony-doped Sn02
or ITO is preferred because electronic conduction is
improved, attaining the effect of preventing the deposition
of dust by virtue of antistatic effect, or electromagnetic
wave shielding effect when the antireflection film of the
present invention is used in CRT. In order to make the
hard coat layer transparent, it is preferred for the
particle diameter of fine particles having a high
refractive index to be not more than 400 nm.
In the hard coat layer, when an ionizing radiation
curing resin is used as the binder resin, the ionizing
radiation curing resin may be cured by the conventional
curing method usually employed for curing ionizing
radiation curing resins, that is, applying an electron beam
or ultraviolet light. For example, in the case of curing
with an electron beam, use may be made of an electron beam
or the like having an energy of 50 to 1000 KeV, preferably
100 to 300 Kev, emitted from various electron beam
accelerators, such as a Cockcroft-Walton (type)
accelerator, a van de Graaff accelerator, a resonance
transformer accelerator, an insulation core transformer
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accelerator, a linear accelerator, a dynatron accelerator,
and a high frequency accelerator. On the other hand, in
the case of curing with W, use may be made of ultraviolet
light or the like emitted from an ultrahigh pressure
mercury lamp, a high pressure mercury lamp, a low pressure
mercury lamp, a carbon arc, a xenon arc, a metal halide
lamp, and the like.
Antireflection in Interface
Fig. 1 is a diagram showing a laminate film comprising
a triacetyl cellulose film (hereinafter referred to as "TAC
substrate film") 1 having a refractive index of 1.49 and,
formed thereon, a vapor-deposited SiOx film 3 having a
refractive index of 1.46. A spectral reflectance curve for
this laminate film is shown in Fig. 5.
Fig. 2 is a diagram showing a laminate film comprising
a TAC substrate film 1 having a refractive index of 1.49
and, formed thereon in the following order, a hard coat
layer (hereinafter referred to as "HC layer") 2 having a
refractive index of 1.49 and a vapor-deposited SiOx film 3
having a refractive index of 1.46. A spectral reflectance
curve for this laminate film is shown in Fig. 6.
Fig. 3 is a diagram showing a laminate film having the
same layer construction as the laminate film shown in Fig.2
except that the refractive index of the HC layer has been
enhanced, that is, a laminate film comprising a TAC
substrate film 1 having a refractive index of 1.49 and,
formed thereon in the following order, a 6 um-thick HC
layer 2 having a refractive index of 1.55 and a vapor-
deposited SiOx film 3 having a refractive index of 1.46.
A spectral reflectance curve for this laminate film is
shown in Fig. 7. When the spectral reflectance curve shown
in Fig. 7 is put on that shown in Fig. 6, it is apparent
that the top portions of the waves around the target
wavelength 550 nm (to which the eye of the human being is
said to be most sensitive) overlap with the curve shown in
Fig. 6. In the other wavelengths in Fig. 7, the
reflectance becomes low due to a reduction in the height of
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the waves.
This indicates that the reflection in the interface of
layers can be prevented by making the refractive index of
the HC layer located between the vapor-deposited SiOX layer
and the TAC substrate film higher than that of the other
layers.
The spectral reflectance curve shown in Fig. 8
indicates that the pitch of the wave increases with
decreasing the film thickness. In this case, it is
apparent that the tendency of reflectance observed as a
relationship between Fig. 5 and Fig. 8 is the same as the
tendency of reflectance observed as a relationship between
Fig. 6 and Fig. 7. The laminate film having a spectral
reflectance curve shown in Fig. 8 comprises substrate TAC
(refractive index 1.49)/HC layer (film thickness 3 um,
refractive index 1.55)/antireflection layer (film thickness
95 nm, refractive index 1.46).
Fig. 9 shows a spectral reflectance curve for a
laminate film having the same layer construction as the
laminate film shown in Fig. 3 except that the refractive
index of the HC layer has been enhanced to 1.65. It is
apparent that an increase in the refractive index of the HC
layer increases the size (depth) of the wave, enabling the
refractive index to be lowered.
Fig. 4 shows a laminate film comprising a saponified
TAC substrate film 1 having a refractive index of 1.49 and,
provided thereon in the following order, a primer layer 4
having a refractive index of 1.55, a HC layer 2, having a
refractive index of 1.65, comprising a resin with fine
particles of Zn0 having a high refractive index being
dispersed therein, and a vapor-deposited SiOx film 3 having
a refractive index of 1.46. In this case, the primer layer
4 has a smaller thickness than the HC layer 2 and a
refractive index approximately intermediate between the
refractive index of the HC layer 2 and that of the TAC
substrate film 1. Fig. 10 shows a spectral reflectance
curve for the laminate film shown in Fig. 4. According to
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the spectral reflectance curve shown in Fig. 10, the
spectral reflectance of this laminate film is intermediate
between the top of the wave and the bottom of the wave in
the spectral reflectance curve shown in Fig. 9, and around
the target wavelength 550 nm, the height of the wave
becomes low, indicating that there occurred such an effect
as could be attained when a material having a lower
refractive index than that of SiOx has been laminated on
the outermost layer.
Since, however, the HC layer and the primer layer are
each a coating formed, for example, by roll coating, the
interface of the HC layer and the transparent substrate
film, it is considered that the interface of the HC layer
and the primer layer, and the interface of the primer and
the transparent substrate film are not clear, creating no
significant difference in refractive index therebetween.
Therefore, in fact, such clear waves as will appear in the
spectral reflectance curve are not likely to occur.
Fig. 11 is a spectral reflectance curve for a laminate
film having a layer construction of TAC substrate film
(refractive index 1.49)/hard coat layer having a high
refractive index (refractive index 1.62)/layer having a low
refractive index (refractive index 1.46). For comparison,
a spectral reflectance curve for a TAC substrate film and
a laminate film having a layer construction of TAC
substrate film (refractive index 1.49)/conventional hard
coat layer (refractive index 1.49)/layer having low
refractive index (refractive index 1.46) are also shown in
Fig. 11. As can be seen Fig. 11, the wave substantially
disappears on the short wavelength side.
Polarizing Plate and Liquid Crystal Display:
The antiglare-antireflection film of the present
invention can be laminated to a polarizing element to
provide a polarizing plate having improved antireflection
properties. A polyvinyl alcohol film, a polyvinyl formal
film, a polyvinyl acetal film, and a saponified film of an
ethylene-vinyl acetate copolymer, these films having been
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colored by iodine or a dye and stretched, may be used in
the polarizing element. In the lamination of the
antiglare-antireflection film to the polarizing plate, when
the transparent substrate film of the antiglare-
antireflection film is, for example, a triacetyl cellulose
film, the triacetyl cellulose film is saponified in order
to improve the adhesion and for destaticization purposes.
The saponification treatment may be carried out before or
after the application of the hard coat on the triacetyl
cellulose film.
Fig. 19 shows an embodiment of a polarizing plate
using the antiglare-antireflection film of the present
invention. In the drawing, a laminate comprising a TAC
(abbreviation for triacetyl cellulose) film 19, an
antiglare'layer 12 having a high refractive index, and a
layer 13 having a low refractive index corresponds to the
antiglare-antireflection film of the present invention, and
this antiglare-antireflection film is laminated on one
surface of a polarizing element 20 with a TAC film 19 being
laminated on the other surface of the polarizing element
20. An adhesive layer is optionally provided between
layers constituting the polarizing plate. It is
particularly preferred to provide an adhesive layer between
the antiglare layer 12 having a high refractive index and
the TAC film 19 as a transparent substrate film. The layer
construction of the polarizing plate shown in Fig. 19 can
be simply represented as TAC film/polarizing
element/antiglare-antireflection film.
Fig. 20 shows an embodiment of a liquid crystal
display using the antiglare-antireflection film of the
present invention. The polarizing plate shown in Fig. 19,
that is, a polarizing plate having a layer construction of
TAC film/polarizing element/antiglare-antireflection film,
is laminated on one surface of a liquid crystal display
element 21 with a polarizing plate having a layer
construction of a TAC film/polarizing element/TAC film
being laminated on the other surface of the liquid crystal
CA 02280473 1999-09-O1
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display element 21. In the liquid crystal display shown in
Fig. 20, a layer having a high refractive index as an
antireflection layer may be provided on the underside of the
TAC film 19 as the lowermost layer, and a layer having a low
refractive index may be further provided on the surface of the
layer having a high refractive index remote from the TAC film
19. In the case of an STN type liquid crystal display, a
phase plate is inserted between the liquid crystal display
element 21 and the polarizing plate . An adhesive layer is
optionally provided between layers constituting the liquid
crystal display device.
Fig. 14B shows an embodiment of a polarizing plate using
an antireflection film according to another embodiment of the
present invention. In the drawing, numeral 150 designates the
antireflection film of the present invention which, as
described above, comprises a TAC (triacetyl cellulose) film 170
as a transparent substrate film, a hard coat layer 120 having
a high refractive index, and a layer 130 having a low
refractive index. The antireflection film 150 is laminated
on one surface of a polarizing element 160 with a TAC film 170
being laminated on the other surface of the polarizing element
160. An adhesive layer is optionally provided between layers
constituting the polarizing plate. It is particularly
preferred to provide an adhesive layer between the hard coat
layer 120 having a high refractive index and the TAC film 170
as a transparent substrate film. The layer construction of
the polarizing plate shown in Fig. 14B can be simply
represented as TAC film/polarizing element/antireflection
film. According to a further embodiment of the polarizing
plate using the antireflection film of the present invention,
the antireflection film 150 of the present invention may be
laminated onto both surfaces of the polarizing element 160.
Fig. 15 shows an embodiment of a liquid crystal display
device using the antireflection film of the present invention.
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A polarizing plate shown in Fig. 14B, that is, a
polarizing plate having a layer construction of TAC
film/polarizing element/antireflection film, is laminated
on one surface of a liquid crystal display element 180 with
a polarizing plate having a layer construction of TAC
film/polarizing element/TAC film being laminated on the
other surface of the liquid crystal display element 180.
In the liquid crystal display device shown in Fig. 15B, a
hard coat layer 120 having a high refractive index may be
provided on the underside of the TAC film 170 as the
lowermost layer, and a layer 130 having a low refractive
index may be further provided on the surface of the hard
coat layer 120 having a high refractive index remote from
the TAC film 170. In the liquid crystal display device
shown in Fig. 15B, back light is applied through the
underside of the device. In the case of an STN type liquid
crystal display device, a phase plate is inserted between
the liquid crystal display element and the polarizing
plate. An adhesive layer is optionally provided between
layers constituting the liquid crystal display device.
[Example A1]
An 80 um-thick triacetyl cellulose film (FT-W-80
(trade name) manufactured by Fuju Photo Film Co., Ltd.,
refractive index 1.49) was prepared as a transparent
substrate film. Separately, ultrafine Zn0 particles having
a refractive index of 1.9 (ZS-300 (trade name) manufactured
by Sumitomo Cement Co., Ltd.) and an ionizing radiation
curing resin having a refractive index of 1. 52 ( HN-3 ( trade
name) manufactured by Mitsubishi Petrochemical Co., Ltd.)
were mixed together in a weight ratio of 2 . 1. The
resultant resin composition was coated by gravure reverse
coating on the above triacetyl cellulose film to a coating
thickness on a dry basis of 7 um, and the coating was then
dried to remove a solvent contained in the coating.
A matte PET film having a fine uneven surface (X-45
(trade name) manufactured by Toray Industries, Inc.,
thickness 23 um) was laminated to the triacetyl cellulose
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film having a dried resin layer so that the resin layer
faced the matte PET film. The laminate was then exposed to
an electron beam under conditions of 150 kV and 4 Mrad to
cure the resin layer, and the matte PET film was peeled off
from the laminate, thereby forming a fine uneven surface on
the resin layer. Subsequently, SiOx was vapor-deposited on
the fine uneven surface of the resin layer by plasma CVD
process to form a 100 nm-thick SiOx layer ( refractive index
1.46), thereby preparing an antiglare-antireflection film
of Example 1.
The antiglare-antireflection film had a total light
transmittance of 93.5 and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
3H, i.e., an excellent hard property.
Fig. 12A is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 12 an antiglare layer
having a high refractive index with a hard property being
imparted thereto, and numeral 13 a layer having a low
refractive index.
[Example A2]
An 80 um-thick triacetyl cellulose film (FT-W-80
(trade name) manufactured by Fuju Photo Film Co., Ltd.,
refractive index 1.49) was saponified by immersing the
triacetyl cellulose film in a 2 N KOH solution at 60°C for
1 min, thereby preparing a saponified triacetyl cellulose
film which was used as a transparent substrate film
(refractive index 1.49). A primer (refractive index 1.55)
prepared by adding 10 parts by weight of isocyanate as a
curing agent to a vinyl chloride acetate resin (SBP primer
G (trade name) manufactured by Dainichiseika Color
& Chemicals Manufacturing Co. , Ltd. ) was coated by gravure
reverse coating on the above transparent substrate film to
a thickness on a dry basis of 0.7 pm, and the resultant
coating was dried at 60°C for 1 min and then aged at 40°C
CA 02280473 1999-09-O1
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for 2 days. A hard coat layer having an uneven surface was
formed on the primer layer in the same manner as in Example
1. Further, an SiOx layer was formed thereon to prepare an
antiglare-antireflection film of the present example.
The antiglare-antireflection film had a total light
transmittance of 94~ and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
3H, i.e., an excellent hard property.
Fig. 13A is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 14 a primer layer,
numeral 12 an antiglare layer having a high refractive
index with a hard property being imparted thereto, and
numeral 13 a layer having a low refractive index:
[Example A3~
A resin composition prepared by mixing ultrafine Zn0
particles (ZS-300 (trade name) manufactured by Sumitomo
Cement Co., Ltd., refractive index 1.9) and an ionizing
radiation curing resin (HN-2 (trade name) manufactured by
Mitsubishi Petrochemical Co:, Ltd., refractive index 1.54)
together in a weight ratio of 2 . 1 was coated by gravure
reverse coating on a matte PET film (X-45 (trade name)
manufactured by Toray Industries, Inc., thickness 23 um)
having a fine uneven surface to a coating thickness on a
dry basis of 5 um, and the coating was then exposed to an
electron beam under conditions of 150 kV and 3 Mrad,
thereby curing the coating.
Separately from the matte PET film with the resin
layer being formed thereon, a dry laminate resin prepared
by adding 10 parts by weight, based on the adhesive resin,
of isocyanate as a curing agent to a urethane adhesive
(Takenate A310 (trade name)) was coated on the transparent
substrate film used in Example 1 to a coating thickness on
a dry basis of 2 um, and the coating was dried to remove a
solvent contained in the coating.
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The matte PET film with a resin layer being formed
thereon was laminated onto the resultant transparent
substrate film with an adhesive layer being formed thereon
so that the resin layers faced each other. Thereafter, the
laminate was aged at 50°C for 3 days to completely cure the
adhesive layer, and the matte PET film was peeled off.
SiOx was vapor-deposited by the plasma CVD process on the
resin layer having a fine uneven surface to a thickness of
100 nm to form an SiOx layer, thereby preparing an
antiglare-antireflection film of the present example.
The antiglare-antireflection film had a total light
transmittance of 93.8% and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
2H, i.e., an excellent hard property.
Fig. 14A is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 15 an adhesive layer,
numeral 12 an antiglare layer having a high refractive
index with a hard property being imparted thereto, and
numeral 13 a layer having a low refractive index.
[Example A4]
A resin composition prepared by mixing ultrafine Zn0
particles (ZS-300 (trade name) manufactured by Sumitomo
Cement Co., Ltd., refractive index 1.9) and an ionizing
radiation curing resin (HN-2 (trade name) manufactured by
Mitsubishi Petrochemical Co., Ltd., refractive index 1.54)
together in a weight ratio of 2 . 1 was coated by gravure
reverse coating on a matte PET film having a fine uneven
surface (X-45 (trade name) manufactured by Toray
Industries, Inc., thickness 23 p.m) to a coating thickness
on a dry basis of 3 um, and .the coating (resin layer) was
then exposed to an electron beam under conditions of 150 kV
and 3 Mrad, thereby half-curing the resin layer.
Separately from the matte PET film with the half-cured
resin layer being formed thereon, an ionizing radiation
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curing resin (EXG 40-9 (trade name) manufactured by
Dainichiseika Color & Chemicals Manufacturing Co., Ltd.,
refractive index 1.50) was coated by gravure reverse
coating on the triacetyl cellulose film used in Example A1
to a coating thickness on a dry basis of 3 dam, and the
coating was dried to remove a solvent contained in the
coating. Thereafter, the coated triacetyl cellulose film
thus obtained was laminated onto the matte PET film with a
half-cured resin layer being formed thereon so that the
resin layers faced each other. The laminate was irradiated
with an electron beam under conditions of 150 kV and 5 Mrad
to completely cure the resin layer, and the matte PET film
was peeled off from the laminate. A 100 nm-thick SiOx
layer was formed on the resultant resin layer having a fine
uneven surface in the same manner as in Example 1, thereby
preparing an antiglare-antireflection film of the present
example.
The antiglare-antireflection film had a total light
transmittance of 93.5 and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further,, it had a surface pencil hardness of
3H, i.e., an excellent hard property.
Fig. 15A is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 16 a clear hard coat
layer, numeral 12 an antiglare layer having a high
refractive index with a hard property being imparted
thereto, and numeral 13 a layer having a low refractive
index.
[Example A5]
The procedure of Example A2 was repeated to form a
primer layer on a saponified triacetyl cellulose film as a
transparent substrate film. Then, the procedure of Example
A4 was repeated, except that the above film with a primer
layer being formed thereon was used, thereby forming on the
primer layer a clear hard coat layer, an antiglare layer
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having a high refractive index with a hard property being
imparted thereto, and a layer having a low refractive
index. Thus, an antiglare-antireflection film of the
present example was prepared.
The antiglare-antireflection film had a total light
transmittance of 93.5 and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
3H, i.e., an excellent hard property.
Fig. 16 is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 14 a primer layer,
numeral 16 a clear hard coat layer, numeral 12 an antiglare
layer having a high refractive index with a hard property
being imparted thereto, and numeral 13 a layer having a low
refractive index.
[Example A6]
A resin composition prepared by mixing ultrafine Zn0
particles (ZS-300 (trade name) manufactured by Sumitomo
Cement Co., Ltd., refractive index 1.9) and an ionizing
radiation curing resin of dry to the touch type (H-4000
(trade name) manufactured by Mitsubishi Petrochemical Co.,
Ltd., refractive index 1.5) together in a weight ratio of
2 . 1 was coated by gravure reverse coating on a matte PET
film having a fine uneven surface (X-45 (trade name)
manufactured by Toray Industries, Inc., thickness 23 um) to
a coating thickness on a dry basis of 3 Nm, and the coating
( resin layer ) was then dried at 60°C for 1 min until it
became dry to the touch.
Separately from the matte PET film with a resin layer,
which is dry to the touch, being formed thereon, an
ionizing radiation curing resin (EXG 40-9 (trade name)
manufactured by Dainichiseika Color & Chemicals
Manufacturing Co., Ltd., refractive index 1.50) was coated
by gravure reverse coating on a triacetyl cellulose film to
a thickness on a dry basis of 3 um, and the coating was
CA 02280473 1999-09-O1
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then dried to remove a solvent contained in the coating.
Thereafter, the matte PET film with a resin layer being
formed thereon was laminated onto the resultant triacetyl
cellulose film so that the resin layers faced each other.
The laminate was then irradiated with an electron beam
under conditions of 150 kV and 5 Mrad to completely cure
the resin layer, and the matte PET film was peeled off.
SiOx was vapor-deposited on the fine uneven surface
in the same manner as in Example 1, thereby forming a 100
nm-thicklSiO= layer. Thus, an antiglare-antireflection
film of the present example was prepared.
The antiglare-antireflection film had a total light
transmittance of 93.5% and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
2H, i.e., an excellent hard property.
[Example A7]
The procedure of Example A2 was repeated to form a
primer layer on a saponified triacetyl cellulose film as a
transparent substrate film. Then, the procedure of Example
A4 was repeated, except that the above film with a primer
layer being formed thereon was used, thereby forming on the
primer layer a clear hard coat layer, an antiglare layer
having a high refractive index with a hard property being
imparted thereto, and a layer having a low refractive
index. Thus, an antiglare-antireflection film of Example
7 was prepared.
The antiglare-antireflection film had a total light
transmittance of 93.5% and a haze value of 9.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
2H, i.e., an excellent hard property.
[Example A8]
A 1 . 10 . 20 ( weight ratio ) mixture of polymethyl
methacrylate beads having a particle diameter of 5 um, an
ionizing radiation curing resin (HN-2 (trade name)
manufactured by Mitsubishi Petrochemical Co., Ltd.,
CA 02280473 1999-09-O1
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refractive index 1. 54 ) , and ultrafine Zn0 particles ( ZS-300
(trade name) manufactured by Sumitomo Cement Co., Ltd.,
refractive index of 1.9) was coated by gravure reverse
coating on an 80 um-thick triacetyl cellulose film (FT-UV-
80 (trade name) manufactured by Fuju Photo Film Co., Ltd.)
to a thickness on a dry basis of 6 pm, and the coating was
then irradiated with an electron beam under conditions of
150 kV and 4 Mrad. The surface of the cured coating formed
on the triacetyl cellulose film was finely uneven due to
fine beads of polymethyl methacrylate. Subsequently, SiOx
was vapor-deposited on the cured coating in the same manner
as in Example A1 to form a 100 nm-thick SiOx layer, thereby
preparing an antiglare-antireflection film of the present
example.
The antiglare-antireflection film had a total light
transmittance of 94~ and a haze value of 5.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
3H, i.e., an excellent hard property.
Fig. 17 is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 17 an antiglare layer
having a high refractive index, the antiglare layer 17
containing a matte material 18 and having a hard property
imparted thereto, and numeral 13 a layer having a low
refractive index.
[Example A9]
The procedure of Example A2 was repeated to form a
primer layer on a saponified triacetyl cellulose film as a
transparent substrate film. Then, the procedure of Example
A8 was repeated, except that the above film with a primer
layer being formed thereon was used, thereby forming on the
primer layer an antiglare layer having a high refractive
index with a hard property being imparted thereto and a
layer having a low refractive index. Thus, an antiglare-
antireflection film of the present example was prepared.
CA 02280473 1999-09-O1
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The antiglare-antireflection film had a total light
transmittance of 94~ and a haze value of 5.0, indicating
that the film had excellent antireflection and antiglare
properties. Further, it had a surface pencil hardness of
3H, i.e., an excellent hard property.
Fig. 18 is a cross-sectional view showing the layer
construction of the antiglare-antireflection film prepared
in the present example. Numeral 11 designates a
transparent substrate film, numeral 14 a primer layer,
numeral 17 an antiglare layer having a high refractive
index, the antiglare layer 17 containing a matte material
18 and having a hard property imparted thereto, and numeral
13 a layer having a low refractive index.
[Example A10]
A resin composition prepared by mixing ultrafine Zn0
particles (ZS-300 (trade name) manufactured by Sumitomo
Cement Co., Ltd., refractive index 1.9) and. an electron
beam curing resin (HN-3 (trade name) manufactured by
Mitsubishi Petrochemical Co., Ltd.) together in a weight
ratio of 2 . 1 was coated by gravure reverse coating on a
PET film (T-600 (trade name) manufactured by Diafoil Co.,
Ltd., thickness 50 um) having a fine uneven surface to a
coating thickness on a dry basis of 7 um, and the coating
was then exposed to an electron beam under conditions of an
accelerating voltage of 175 kV and 4 Mrad to cure the
coating, thereby forming an antiglare layer having a high
refractive index with a hard property imparted thereto.
An adhesive (Takelac (trade name) manufactured by
Takeda Chemical Industries, Ltd.) was coated by gravure
reverse coating on the antiglare layer having a high
refractive index of the PET film to form an adhesive layer.
Subsequently, a triacetyl cellulose film (FT-W-80 (trade
name) manufactured by Fuji Photo Film Co., Ltd., thickness
80 um) was laminated to the PET film through the adhesive
layer to prepare a laminate. The laminate was then aged at
40°C for 3 days, and the PET film was peeled off from the
laminate, thereby transferring the antiglare layer having
CA 02280473 1999-09-O1
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a high refractive index onto the triacetyl cellulose film.
The surface of the antiglare layer having a high refractive
index on the triacetyl cellulose film was finely uneven as
in the surface of the PET film. Further, SiOx was then
vapor-deposited on the antiglare layer having a high
refractive index by the plasma CVD process to form a 100
nm-thick plasma CVD layer having a low refractive index,
thereby preparing an antiglare-antireflection film of the
present example.
The antiglare-antireflection film of the present
invention had a total light transmittance of 94.5% and a
haze value of 0.7, indicating that the film had excellent
antireflection properties. Further, it had a surface
pencil hardness of 3H, i.e., an excellent hard property.
[Comparative Example A]
An 80 um-thick triacetyl cellulose film (FT-W-80
( trade name ) manufactured by Fu j a Photo Fi lm Co . , Ltd . ) was
provided as a substrate. An ionizing radiation curing
resin (EXG 40-9 (trade name) manufactured by Dainichiseika
Color & Chemicals Manufacturing Co., Ltd., refractive index
1.50) was coated by gravure reverse coating on the film to
a coating thickness on a dry basis of 7 um, and the coating
was dried to remove a solvent contained therein.
Thereafter, the matte PET film having a fine uneven surface
(X-45 (trade name) manufactured by Toray Industries, Inc.,
thickness 23 um) was laminated onto the dried resin. The
laminate was irradiated with an electron beam under
conditions of 150 kV and 4 Mrad to cure the resin layer,
and the matte PET film was then peeled off from the
laminate. SiOx was vapor-deposited on the resin layer
having a fine uneven surface to form a 100 nm-thick SiOx
film.
The film of the comparative example had a total light
transmittance of 91.8% and a haze value of 9.0, indicating
that the comparative film had a lower antireflection
property than the films of the above examples of the
present invention. The surface pencil hardness of the
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comparative film was 2H.
[Example All]
The following samples were prepared.
Sample Contact Coefficient Refractive Starting
ankle of friction index material
( )
(Film formation by batch plasma CVD)
SiOx/HC/TAC(1) 50 1.10 1.42 HMDSO+OZ
SiOx/HC/TAC(2) 104 0.44 1.44 HMDSO+Oz
Si0"/HC/TAC(3) 155 0-.-40 1.60 HMDSO+OZ
A 2 . 1 (solid matter weight ratio) mixture of a Zn0
coating solution (ZS-300 manufactured by Sumitomo Cement
Co., Ltd.) and a hard coat resin (40-9 manufactured by
Dainichiseika Color & Chemicals Manufacturing Co., Ltd.)
was diluted with a solution of methyl ethyl ketone
toluene = 1 . 1 to a solid content of 30$ by weight, and
the diluted solution was coated by means of a wire bar on
a release film having a surface treated with an acryl
melamine resin (MC-19 manufactured by Reiko Co., Ltd.) to
a coating thickness on a dry basis of about 6 um. The
resultant coating was dried and cured by EB. Further, an
adhesive (main agent: a 6 . 1 mixture of Takelac A-310
manufactured by Takeda Chemical Industries, Ltd. and
Takenate A-3 as a curing agent manufacture by Takeda
Chemical Industries, Ltd.) was coated thereon to a coating
thickness on a dry basis of 4 um. Then, the coated release
film and the substrate TAC film used in the final product
were laminated on top of the other, and the laminate was
cured by aging at 40°C for 2 days. Thereafter, the release
film was peeled off, and CVD of SiOx was carried out under
the following conditions to prepare an antireflection film.
CA 02280473 1999-09-O1
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Batch plasma CVD apparatus Film forming conditions (1)
Degree of vacuum: 0.45 torr
Power (frequency): 100W (13.56 MHz)
Ratio of ingredients
constituting process gas: He: Oz: monomer = 100:100:1
Flow rate of process gas: He+monomer, 25sccm, O2, 25sccm
Batch plasma CVD apparatus Film forming conditions (2)
Degree of vacuum: 0.45 torr
Power (frequency): 100W (13.56 MHz)
Ratio of ingredients
constituting process gas: He: Oz: monomer = 100:100:4.6
Flow rate of process gas: He+monomer, 25sccm, O2, 25sccm
Batch plasma CVD apparatus Film forming conditions (3)
Degree of vacuum: 0.45 torr
Power (frequency): 100W (13.56 MHz)
Ratio of ingredients
constituting process gas: He: Oz: monomer = 100:100:10
Flow rate of process gas: He+monomer, 25sccm, OZ, 25sccm
Vapor-depositing machine: A handmade device using
components manufactured by
Anelva Engineering Corporation
and other components
Vapor-depositing HMDSO (hexamethyldisiloxane)
substance: as monomer+OZ
(Samples (1), (2), and (3)
were prepared by varying
HMDSO: OZ )
Carrier gas: He
Substrate temp.. Room temperature
Vapor deposition rate: 1.3 ~/S
Film thickness: 1000
[Example A12]
The following samples were prepared.
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Sample Contact Coefficient Refrac- Starting
angle of friction tive material
~
( ) index
(Film formation by continuous CVD)
plasma
SiOx/HC/TAC(1) 83 0.90 1.42 HMDSO+OZ
SiOx/HC/TAC(2) 102 0.47 1.44 HMDSO+OZ
SiOx/HC/TAC(3) 162 0.40 1.50 HMDSO+02
(Film formation by continuous CVD follow ed by
plasma
corona treatment of the film on its surface)
SiOx/HC/TAC(2) 58 0.92 1.44 HMDSO+Oz
A 2 . 1 (solid matter weight ratio) mixture of a Zn0
coating solution (ZS-300 manufactured by Sumitomo Cement
Co., Ltd.) and a hard coat resin (40-9 manufactured by
Dainichiseika Color & Chemicals Manufacturing Co., Ltd.)
was diluted with a solution of methyl ethyl ketone
toluene = 1 . 1 to a solid content of 30$ by weight, and
the diluted solution was coated by means of a wire bar on
a 25 um-thick matte PET film having a fine uneven surface
(Emblet PTH manufactured by Unitika Ltd.) to a coating
thickness on a dry basis of about 6 um. The resultant
coating was dried and cured by EB. Further, an adhesive
(main agent: a 6 . 1 mixture of Takelac A-310 manufactured
by Takeda Chemical Industries, Ltd. and Takenate A-3 as a
curing agent manufacture by Takeda Chemical Industries,
Ltd.) was coated thereon to a coating thickness on a dry
basis of 4 um. Then, the coated release film and the
substrate TAC film used in the final product were laminated
on top of the other, and the laminate was cured by aging at
40°C for 2 days. Thereafter, the matted PET film was
peeled off, and plasma CVD of SiOx was carried out under
the following varied HMDSO (monomer) . Oz conditions to
prepare antireflection films. For the conditions (2), the
corona discharge treatment to impart hydrophilicity
resulted in reduced contact angle of the resultant film
with water and increased coefficient of friction.
CA 02280473 1999-09-O1
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Continuous plasma CVD Film forming conditions (1)
apparatus
Degree of vacuum 5x10-2 torr
Power (frequency) 30 kW (40 kHz)
Ratio of ingredients
constituting process gas He:O2:monomer = 16:90:1
Machine speed 10 m/min
Continuous plasma CVD Film forming conditions (2)
apparatus
Degree of vacuum ~ 5x10'2 torr
Power (frequency) 30 kW (40 kHz)
Ratio of ingredients
constituting process gas He: OZ: monomer = 16:16:1
Machine speed 10 m/min
Continuous plasma CVD Film forming conditions (3)
apparatus
Degree of vacuum 5x10'2 torr
Power (frequency) 30 kW (40 kHz)
Ratio of ingredients
constituting process gas He: OZ: monomer = 16:6:1
Machine speed 10 m/min
[Reference Example A1]
The following samples were prepared.
Sample Contact Coefficient Refrac- Starting
ankle of friction tive material
( ) index
(Film formation by batch plasma CVD)
SiOx/HC/TAC 43.9 1.13 1.44 SiH4
A 2 . 1 (solid matter weight ratio) mixture of a Zn0
coating solution (ZS-300 manufactured by Sumitomo Cement
Co., Ltd.) and a hard coat resin (C-19 manufactured by
Dainichiseika Color & Chemicals Manufacturing Co., Ltd.)
was diluted with a solution of methyl ethyl ketone
toluene = 1 . 1 to a solid content of 30~ by weight, and
the diluted solution was coated by means of a wire bar on
CA 02280473 1999-09-O1
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a release film having a surface treated with an acryl-
melamine resin (MC-19 manufactured by Reiko Co., Ltd.) to
a coating thickness on a dry basis of about 6 um. The
resultant coating was dried and cured by EB. Further, an
adhesive (main agent: a 6 . 1 mixture of Takelac A-310
manufactured by Takeda Chemical Industries, Ltd. and
Takenate A-3 as a curing agent manufacture by Takeda
Chemical Industries, Ltd.) was coated thereon to a coating
thickness on a dry basis of 4 um. Then, the coated release
film and the substrate TAC film used in the final product
were laminated on top of the other, and the laminate was
cured by aging at 40°C for 2 days. Thereafter, the release
film was peeled off, and CVD of SiOx was carried out under
the following conditions to prepare an antireflection film.
Batch plasma CVD Film forming condition
ar~r~aratm
Degree of vacuum: 0.45 torr
Power (frequency): 100 W (13.56 MHz)
Ratio of ingredients
constituting process gas: He:O2:SiH4 = 100:100:4.6
Flow rate of process gas: He+SiH4, 25sccm, O2, 25sccm
Vapor-depositing machine: A handmade device using
components manufactured by
Anelva Engineering Corporation
and other components
Vapor-depositing
substance: SiH4+02
Carrier gas: He
Substrate temp.. Room temperature
Vapor deposition rate: 1.3 ~/S
Film thickness: 1000 A
[Reference Example A2]
The following samples were prepared.
CA 02280473 1999-09-O1
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Sample Contact Coefficient Refrac- Starting
ankle of friction tive material
( ) index
(Film formation by vacuum deposition)
SiOz/HC/TAC 32 1.50 1.44 Si02
A 2 . 1 (solid matter weight ratio) mixture of a Zn0
coating solution (ZS-300 manufactured by Sumitomo Cement
Co., Ltd.) and a hard coat resin (40-9 manufactured by
Dainichiseika Color & Chemicals Manufacturing Co., Ltd.)
was diluted with a solution of methyl ethyl ketone
toluene = 1 . 1 to a solid content of 30% by weight, and
the diluted solution was coated by means of a wire bar on
a release film having a surface treated with an acryl-
melamine resin (MC-19 manufactured by Reiko Co., Ltd.) to
a coating thickness on a dry basis of about 6 um. The
resultant coating was dried and cured by EB. Further, an
adhesive (main agent: a 6 . 1 mixture of Takelac A-310
manufactured by Takeda Chemical Industries, Ltd. and
Takenate A-3 as a curing agent manufacture by Takeda
Chemical Industries, Ltd.) was coated thereon to a coating
thickness on a dry basis of 4 um. Then, the coated release
film and the substrate TAC film used in the final product
were laminated on top of the other, and the laminate was
cured by aging at 40°C for 2 days. Thereafter, the release
film was peeled off, and vapor-deposition of Si02 was
carried out under the following conditions to prepare an
antireflection film.
Vapor-depositing machine: Synchron BMC-700
Vapor-depositing
substance: SiOz
Degree of vacuum: 4x10'2 torr
Substrate temp.. Room temperature
Vapor-deposition: EB heating
Accelerating voltage: 8 kV
Emission: 40 mA
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Vapor deposition rate: 4 ~/S
Film thickness: 1000
[Reference Example A3]
The following samples were prepared.
Sample Contact Coefficient Refrac- Starting
ankle of friction tive material
( ) index
(Film formation by vacuumdeposition)
SiOx/HC/TAC 11.2 1.12 1.50 Si0
SiOx/HC/TAC 12.3 1.89 1.50 Si0
A 2 . 1 (solid matter weight ratio) mixture of a Zn0
coating solution (ZS-300 manufactured by Sumitomo Cement
Co., Ltd.) and a hard coat resin (40-9 manufactured by
Dainichiseika Color & Chemicals Manufacturing Co., Ltd.)
was diluted with a solution of methyl ethyl ketone
toluene = 1 . 1 to a solid content of 30°s by weight, and
the diluted solution was coated by means of a wire bar on
a release film having a surface treated with an acryl-
melamine resin (M~-19 manufactured by Reiko Co., Ltd.) to
a coating thickness on a dry basis of about 6 dam. The
resultant coating was dried and cured by EB. Further, an
adhesive (main agent: a 6 . 1 mixture of Takelac A-310
manufactured by Takeda Chemical Industries, Ltd. and
Takenate A-3 as a curing agent manufacture by Takeda
Chemical Industries, Ltd.) was coated thereon to a coating
thickness on a dry basis of 4 um. Then, the coated release
film and the substrate TAC film used in the final product
were laminated on top of the other, and the laminate was
cured by aging at 40°C for 2 days. Thereafter, the release
film was peeled off, and vapor-deposition of Si0 was
carried out under the following conditions to prepare an
antireflection film.
CA 02280473 1999-09-O1
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Vapor-depositing machine: Synchron BMC-700
Vapor-depositing
substance: Si0
Degree of vacuum: 4x10'z torr
Substrate temp.. Room temperature
Vapor-deposition: EB heating
Accelerating voltage: 5 kV
Emission: 40 mA
Vapor deposition rate: 4 ~1/S
Film thickness: 1000
Since the optical functional membrane and the optical
functional film of the present invention comprise a
particular film of SiOx wherein x is 1.50 5 x s 4.00, they
have excellent moistureproofness and anitfouling property,
good film hardness, excellent adhesion to a resin layer,
and can reduce heat damage to the transparent substrate
film at the time of forming the SiOx film as compared with
the case where the film is formed by the vapor phase growth
process.
According to the antiglare-antireflection film of the
present invention, a layer having a low refractive index,
which is lower than the refractive index of the antiglare
layer, is formed on the antiglare layer, and the refractive
index of the antiglare layer is higher than that of a layer
in contact with the antiglare layer in its surface remote
from the layer having a low refractive index, enabling the
reflection of light at the interface of the antiglare layer
and the layer in contact with the antiglare layer in its
surface remote from the layer having a low refractive index
to be reduced. Therefore, the antiglare-antireflection
film of the present invention is excellent in the antiglare
property as well as in the antireflection effect.
The use of functional fine particles as fine particles
having a high refractive index, for example, Zn0 or Ti02,
in the antiglare layer of the antiglare-antireflection film
of the present invention can impart, besides the antiglare
CA 02280473 1999-09-O1
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antireflection properties, other various functions, for
example, W shielding effect.
[Example B1]
An 80 um-thick triacetyl cellulose film (FT-W-80
(trade name) manufactured by Fuju Photo Film Co., Ltd.,
refractive index 1.49) was prepared as a transparent
substrate film. Separately, ultrafine Zn0 particles (ZS
300 (trade name) manufactured by Sumitomo Cement Co. , Ltd. ,
refractive index 1.9) and an ionizing radiation curing
resin (HN-2 (trade name) manufactured by Mitsubishi
Petrochemical Co., Ltd., refractive index 1.54) were mixed
together in a weight ratio of 2 . 1. The resultant resin
composition was coated by gravure reverse coating on the
above triacetyl cellulose film to a coating thickness on a
dry basis of 7 um, and the coating was then irradiated with
an electron beam under conditions of 150 kV and 3 Mrad to
cure the coating, thereby preparing a hard coat layer
having a high refractive index.
Then, SiOx ( refractive index 1. 46 ) was vapor-deposited
on the above hard coat layer by the plasma CVD process to
form a 100 nm-thick SiOx film as a layer having a low
refractive index.
The antireflection film of Example 1 had a total light
transmittance of 94.2$ and a haze value of 1.0, indicating
that the film had excellent antireflection properties.
Further, it had a surface pencil hardness of 3H, i.e., an
excellent hard property.
Fig. 12B is a cross-sectional view showing the layer
construction of the antireflection film prepared in the
present example 1. Numeral 110 designates a transparent
substrate film, numeral 120 a hard coat layer having a high
refractive index, and numeral 130 a layer having a low
refractive index.
[Example B2]
An 80 um-thick triacetyl cellulose film (FT-W-80
(trade name) manufactured by Fuju Photo Film Co., Ltd. ) was
saponified by immersing the triacetyl cellulose film in a
CA 02280473 1999-09-O1
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2 N KOH solution at 60°C for 1 min, thereby preparing a
saponified triacetyl cellulose film which was used as a
transparent substrate film (refractive index 1.49).
Separately, primer (refractive index 1.55) prepared by
adding 10 parts by weight of isocyanate as a curing agent
to a vinyl chloride acetate resin (SBP primer G (trade
name) manufactured by Dainichiseika Color & Chemicals
Manufacturing Co., Ltd.) was coated by gravure reverse
coating on the above transparent substrate film to a
thickness on a dry basis of 0.7 um, and the resultant
coating was dried at 60°C for 1 min and then aged at 40°C
for 2 days. A hard coat layer having a high refractive
index and a layer having a low refractive index were formed
on the resultant film in the same manner as in Example B1.
The antireflection film of the present example thus
formed had a total light transmittance of 94.5% and a haze
value of 1.0, indicating that the film had excellent
antireflection properties. Further, it had a surface
pencil hardness of 3H, i.e., an excellent hard property.
Fig. 13B is a cross-sectional view showing the layer
construction of the antireflection film prepared in the
present example. Numeral 110 designates a transparent
substrate film, numeral 140 a primer layer, numeral 120 a
hard coat layer having a high refractive index, and numeral
130 a layer having a low refractive index.
[Example B3)
An antireflection film was prepared in the same manner
as in Example B2, except that, instead of the SiOX film by
the plasma CVD process, a layer formed by coating an
ionizing radiation curing resin containing 10% by weight of
ultrafine particles of magnesium fluoride (refractive index
1.4)(DT-1 (trade name) manufactured by Sumitomo Cement Co.,
Ltd., refractive index 1.42) by gravure reverse coating to
a coating thickness on a dry basis of 100 nm and
irradiating the resultant coating with an electron beam
under conditions of 150 kV and 2 Mrad to cure the coating
CA 02280473 1999-09-O1
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was used as the layer having a low refractive index. The
coating had a refractive index of 1.42.
The antireflection film of the present example thus
prepared had a total light transmittance of 94.7 and a
haze value of 1.0, indicating that. the film had excellent
antireflection properties. Further, it had a surface
pencil hardness of H, i.e., an excellent hard property.
[Example B4]
An antireflection film was prepared in the same manner
as in Example B2, except that the formation of a hard coat
layer having a high refractive index and a layer having a
low refractive index was varied as follows. Specifically,
a primer layer was formed on a saponified triacetyl
cellulose film, and a resin composition prepared by mixing
ultrafine particles of Zn0 (ZS-300 (trade name)
manufactured by Sumitomo Cement Co., Ltd., refractive index
1.9) and an ionizing radiation curing resin (EXG 40-9:
(trade name) manufactured by Dainichiseika Color &
Chemicals Manufacturing Co., Ltd., refractive index 1.49)
together in a weight ratio of 2 . 1 was coated by gravure
reverse coating to a coating thickness on a dry basis of 7
um, and the coating was irradiated with an electron beam
under conditions of 150 kV and 3 Mrad to cure the coating.
A 100 nm-thick SiOx film was formed thereon in the same
manner as in Example B1.
The antireflection film of the present example thus
prepared had a total light transmittance of 93.8% and a
haze value of 1.0, indicating that the film had excellent
antireflection properties. Further, it had a surface
pencil hardness of 3H, i.e., an excellent hard property.
[Example B5]
A resin composition prepared by mixing an electron
beam curing resin (HN-3 (trade name) manufactured by
Mitsubishi Petrochemical Co., Ltd.) and ultrafine particles
of Zn0 ( ZS-300 ( trade name ) manufactured by Sumitomo Cement
Co. , Ltd. , refractive index 1. 9 ) together in a weight ratio
of 2 . 1 was coated by gravure reverse coating on a PET
CA 02280473 1999-09-O1
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film having a smooth surface (T-600 (trade name)
manufactured by Diafoil Co., Ltd., thickness 50 pm) to a
coating thickness on a dry basis of 7 um, and the coating
was then irradiated with an electron beam under conditions
of an accelerating voltage of 175 kV and 4 Mrad, thereby
curing the coating to prepare a hard coat layer having a
high refractive index. An adhesive (Takelac (trade name)
manufactured by Takeda Chemical Industries, Ltd.) was
coated by gravure reverse coating on the resultant hard
coat layer having a high refractive index of the PET film
to prepare an adhesive layer. Subsequently, a triacetyl
cellulose film ( FT-W-80 ( trade name ) manufactured by Fuj i
Photo Film Co., Ltd., thickness 80 um) was laminated to the
PET film through the adhesive layer to prepare a laminate.
The laminate was then aged at 40°C for 3 days, and the PET
film was peeled off from the laminate, thereby transferring
the hard coat layer having a high refractive index to the
triacetyl cellulose film. Further, SiOx was vapor-
deposited on the hard coat layer having a high refractive
index of the triacetyl cellulose film by the plasma CVD
process to form a 100 nm-thick plasma CVD layer having a
low refractive index, thereby preparing an antireflection
film of the present example.
The antireflection film of the present example thus
prepared had a total light transmittance of 94.5$ and a
haze value of 0.7, indicating that the film had excellent
antireflection properties. Further, it had a surface
pencil hardness of 3H, i.e., an excellent hard property.
[Comparative Example H1]
An ionizing radiation curing resin (EXG 40-9: (trade
name) manufactured by Dainichiseika Color & Chemicals
Manufacturing Co., Ltd., refractive index 1.49) was coated
by gravure reverse coating on an 80 ~m-thick triacetyl
cellulose film (FT-W-80 (trade name) manufactured by Fuju
Photo Film Co., Ltd., refractive index 1.49) as a
transparent substrate film to a coating thickness on a dry
basis of 7 um, and the coating was irradiated with an
CA 02280473 1999-09-O1
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electron beam under conditions of 150 kV and 3 Mrad to cure
the coating. SiOx was vapor-deposited by the plasma CVD
process on the cured coating in the same manner as in
Example B1, thereby forming a 100 nm-thick SiOx layer.
The film of Comparative Example B1 thus prepared had
a total light transmittance of 92.7$ and a haze value of
1.0, indicating that the film had lower antireflection
properties than the films of the examples of the present
invention. Further, it had a surface pencil hardness of
2H.
[Comparative Example B2]
An ionizing radiation curing resin (EXG 40-9: (trade
name) manufactured by Dainichiseika Color & Chemicals
Manufacturing Co., Ltd., refractive index 1.49) was coated
by gravure reverse coating on an 80 pm-thick triacetyl
cellulose film ( FT-W-80 ( trade name ) manufactured by Fuju
Photo Film Co., Ltd., refractive index 1.49) as a
transparent substrate film to a coating thickness on a dry
basis of 0.3 um, and the coating was irradiated with an
electron beam under conditions of 150 kV and 3 Mrad to cure
the coating. SiOx was vapor-deposited by the plasma CVD
process on the cured coating in the same manner as in
Example B1, thereby forming a 100 nm-thick SiOx layer. The
antireflection film of Comparative Example B2 thus prepared
had a total light transmittance of 92.7$ and a haze value
of 1.0, indicating that the film had lower antireflection
properties than the films of the examples of the present
invention. Further, it had a surface pencil hardness of B.
According to the antireflection film of the present
invention, a layer having a low refractive index is formed
on a hard coat layer, and the refractive index of the hard
coat layer is higher than that of a layer in contact with
the hard coat layer in its surface remote from the layer
having a low refractive index. By virtue of this
constitution, the antireflection film of the present
invention has an antireflection property and, at the same
time, a hard property and, further, can reduce the
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reflection of light in the interface of the hard coat layer
and the layer in contact with the hard coat layer.
Therefore, the provision of the antireflection film of the
present invention to, for example, a polarizing plate or a
liquid crystal display device, by means of lamination or
application can impart the above effect of the
antireflection film to the a polarizing plate or a liquid
crystal display device.
In the antireflection film of the present invention,
when an SiOx film formed by the plasma CVD process is used
as the layer having a low refractive index, the
antireflection film has excellent moistureproofness, gas
barrier property, transparency, scratch resistance, and
adhesion in addition to the above effects.
