U.S. patent application number 09/053690 was filed with the patent office on 2001-07-26 for a durable and layered photochromic film that employs a gas barrier film layer.
Invention is credited to KAWASHIMA, TADASU.
Application Number | 20010009721 09/053690 |
Document ID | / |
Family ID | 13839296 |
Filed Date | 2001-07-26 |
United States Patent
Application |
20010009721 |
Kind Code |
A1 |
KAWASHIMA, TADASU |
July 26, 2001 |
A DURABLE AND LAYERED PHOTOCHROMIC FILM THAT EMPLOYS A GAS BARRIER
FILM LAYER
Abstract
It is an object of the present invention to provide a highly
durable photochromic film retaining a photochromic activity for a
long time even when used under high temperture and high humidity
conditions. A durable photochromic film comprising a coloring
material layer containing a photochromic material and a
phototransmissive deposition film laminated to said coloring
material layer is disclosed.
Inventors: |
KAWASHIMA, TADASU; (TOCHIGI,
JP) |
Correspondence
Address: |
DAVID R. METZGER, ESQ.
SONNENSCHEN NATH & ROSENTHAL
P.O. BOX #061080, WACKER DRIVE STATION
SEARS TOWER
CHICAGO
IL
60606-1080
US
|
Family ID: |
13839296 |
Appl. No.: |
09/053690 |
Filed: |
April 2, 1998 |
Current U.S.
Class: |
428/475.8 ;
428/476.1; 428/483; 428/516; 428/517 |
Current CPC
Class: |
Y10T 428/31743 20150401;
Y10T 428/31746 20150401; Y10T 428/31917 20150401; Y10T 428/31678
20150401; Y10T 428/31913 20150401; Y10S 428/913 20130101; Y10T
428/31931 20150401; B32B 27/32 20130101; G03C 1/685 20130101; Y10T
428/31797 20150401; Y10T 428/31855 20150401 |
Class at
Publication: |
428/475.8 ;
428/476.1; 428/483; 428/516; 428/517 |
International
Class: |
B32B 027/34; B32B
027/30; B32B 027/36 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 1997 |
JP |
HEI 9-84747 |
Claims
What is claimed is:
1. A durable photochromic film comprising a coloring material layer
containing a photochromic material and a phototransmissive
deposition film laminated to said coloring material layer.
2. A durable photochromic film comprising a coloring material layer
containing a photochromic material and a phototransmissive
deposition film laminated to each side of said coloring material
layer.
3. A durable photochromic film according to claim 1 wherein said
deposition film has oxygen permeability of 0.5 (cc/m.sup.2.day.atm)
or less when a polyolefin film is laminated to each face of said
deposition film.
4. A durable photochromic film according to claim 2 wherein said
deposition film has oxygen permeability of 0.5 (cc/m.sup.2.day.atm)
or less when a polyolefin film is laminated to each face of said
deposition film.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a photochromic film having
a photochromic activity to develop or change color by exposure to
light, and more specifically, it relates to a durable photochromic
film retaining said photochromic activity for a long time.
[0003] 2. Description of the Prior Art
[0004] There have previously been well known so-called photochromic
materials which absorb light in the UV region to develop or change
color and fade color when UV rays are shut out.
[0005] Photochromic products in the form of a thin plate
incorporating such a photochromic material in a resin binder
sandwiched between glasses have widely been used in glasses for
automobiles, glazings, etc. (for example, see JUA No.
50110/89).
[0006] However, the conventional photochromic products could not
retain the unique activity of photochromics which develop or change
color by exposure to light. Particularly when used outdoors during
summer, the product life was shortened.
[0007] We investigated the cause of the above problem and found
that photochromic materials deteriorate by contact with heat,
oxygen and moisture, particularly oxygen in addition to exposure to
UV rays. Particularly when used under high temperature and high
humidity conditions, photochromic materials rapidly
deteriorated.
[0008] Accordingly, an object of the present invention is to
provide a highly durable photochromic film retaining a photochromic
activity for a long time even when used under high temperature and
high humidity conditions.
SUMMARY OF THE INVENTION
[0009] In order to attain the above object, the present invention
provides a durable photochromic film comprising a coloring material
layer containing a photochromic material and a phototransmissive
deposition film laminated to said coloring material layer.
[0010] The present invention also provides a durable photochromic
film wherein said deposition film is laminated to each side of said
coloring material layer.
[0011] The present invention further provides a durable
photochromic film wherein said deposition film has oxygen
permeability of 0.5 (cc/m.sup.2.day.atm) or less when a polyolefin
film is laminated to each face of said deposition film.
[0012] According to the present invention, the coloring material
layer consisting of a photochromic material and a base polymer is
protected by the phototransmissive deposition film.
[0013] Namely, the phototransmissive deposition film is permeable
to UV rays to retain the photochromic activity. The deposition film
as a whole has low oxygen permeability by the presence of the
deposit to prevent a photochromic material in the coloring material
layer from coming into contact with oxygen and thus can retain the
photochromic activity.
[0014] Unlike saran resins or ethylene resins previously known as
oxygen barrier films, the phototransmissive deposition film
according to the present invention does not increase the oxygen
permeability or vapor permeability with variation of the
environmental temperature used.
[0015] Therefore, the photochromic film according to the present
invention can retain the photochromic activity for a long time even
when it is used under high temperature and high humidity
conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows a cross-section of a durable photochromic film
according to the present invention;
[0017] FIG. 2 shows another cross-section of a durable photochromic
film according to the present invention; wherein 1, 4 represent a
durable photochromic film, 2, 5 represent a coloring material
layer, 3a, 3b, 6a, 6b represent a phototransmissive deposition
film, and 7 represents an adhesive layer (self-adhesive layer).
DETAILED DESCRIPTION OF THE INVENTION
[0018] A photochromic film according to the present invention
generally comprises a coloring material layer 2 containing a
photochromic material and phototransmissive deposition films 3a, 3b
laminated to each side of said coloring material layer, as shown in
FIG. 1. If the photochromic film is to be adhered to a substrate
with low oxygen permeability such as glass, the deposition film on
the substrate side may be omitted.
[0019] Then, the photochromic film according to the present
invention may be adhered to a substrate via an adhesive layer 7
formed on any one face of the deposition films 6a, 6b as shown in
FIG. 2.
[0020] In an embodiment not shown, the adhesive layer 7 may be
formed on each face of the deposition films 6a, 6b. When the
deposition film 6a or 6b is to be laminated to only one side of the
coloring material layer 5, the adhesive layer 7 may conveniently be
formed on the side of the coloring material layer 5.
[0021] Now, the photochromic film 4 shown in FIG. 2 is specifically
explained.
[0022] The coloring material layer 5 in the photochromic film 4
according to the present invention consists of a photochromic
material and a base polymer.
[0023] The photochromic material is not specifically limited but
may be chosen from any known types. Specific examples may include
organic photochromic materials such as azobenzene compounds,
thioindigo compounds, spiropyran compounds, fulgide compounds,
triphenylmethane compounds, spirooxazine compounds, viologen
compounds, salicyldineanil compounds, etc.
[0024] The base polymer is also non-limitative but may be chosen
from any known types. Specific examples may include rubber resins,
polyester resins, polyurethane resins, polyether resins,
polycarbonate resins, fluorine resins, silicone resins, acrylic
resins, styrene resins, etc.
[0025] Among these base polymers, rubber resins which show a weight
gain of 1% or less, more preferably 0.1% or less after immersion in
water at 23.degree. C. for 24 hours according to ASTM D570 are
preferred in terms of humidity resistance. Among said rubber
resins, so-called hydrogenated rubber resins in which hydrogen are
added into molecules are preferred in terms of weather resistance.
Specifically, styrene copolymers such as SEBS
(styrene-ethylene-butyrene-styrene), SEPS
(styrene-ethylene-propylen- e-styrene) may be mentioned.
[0026] The thickness of the coloring material layer 5 consisting of
these photochromic material and base polymer is not specifically
limited, but generally ranges from 5 to 100 microns.
[0027] The deposition film 6a or 6b consists of a base and a
deposition layer.
[0028] The base may be a phototransmissive plastic film such as
resin films including polyester, polyethylene, polypropylene,
nylon, vinyon, etc. The base may be preliminarily surface-treated
by corona, plasma or other means to facilitate adhesion of the
deposition layer to the base.
[0029] The deposition layer can be formed by conventional
techniques, such as vacuum deposition, ion plating, sputtering,
plasma deposition, CDV.
[0030] The deposit may be a silicon oxide, a metal or a metal oxide
such as ITO (Indium Tin Oxide), titanium oxide and aluminium
oxide.
[0031] The deposition films 6a, 6b according to the present
invention must have a sufficient phototransmissivity and low oxygen
permeability.
[0032] The phototransmissivity can be expressed as a
transmissivity, practically of 15% or more. If the transmissivity
is less than 15%, any color development or color change of the
photochromic material can not be seen through the deposition film.
When the transmissivity is low, UV rays can not readily penetrate
the deposition film so that the photochromic material can not
sufficiently develop or change color.
[0033] In order to keep the above transmissivity, the thickness of
the deposition layer should be controlled at 100 to 10000
angstroms.
[0034] It is also required that the deposition films 6a, 6b should
have low oxygen permeability and should not increase said oxygen
permeability with variation of the environmental temperature
used.
[0035] The present invention may be effective if the deposition
film has oxygen permeability of 0.5 (cc/m.sup.2.day.atm) or less
when a polyolefin film is laminated to each face of the deposition
film in a temperature range from normal temperatures to the
temperatures at which photochromic films are usually used (about
40.degree. C.). The vapor permeability is preferably 0.5
(g/m.sup.2.day) or less.
[0036] Deposition films with such properties are commercially
available, such as "TEC BARRIER" series made by Mitsubishi Chemical
Corp. or "MOS film" series made by Oike Industry Corp.
[0037] The adhesive layer 7 to be adhered to a substrate is not
specifically limited but may be chosen from any known types.
[0038] Examples include acrylic resins, methacrylic resins, epoxy
resins, polyurethane resins, polyester resins, rubber resins or
petroleum resins.
[0039] The above-described photochromic film according to the
present invention can be prepared by the following process, for
example.
[0040] A coloring material layer solution containing a photochromic
material and a base polymer dissolved in a solvent is prepared and
coated on a release film, and the solvent is dried off to form a
coloring material layer.
[0041] Then, a deposition film is faced to one surface of said
coloring material layer and both are laminated.
[0042] Said release film is released and a deposition film is
laminated to the other surface of the coloring material layer to
obtain an intended photochromic film. Alternatively, an intended
photochromic film can be obtained by directly coating a coloring
material layer solution on a deposition film without using a
release film to form a coloring material layer and laminating
another deposition film on a surface of said coloring material
layer.
[0043] The coloring material layer may also be formed by providing
a film of a base polymer incorporating a photochromic material,
instead of coating a solution as described above.
[0044] Then, an adhesive layer may be directly coated on the
resulting photochromic film described above or laminated to a
preformed deposition film.
[0045] The following examples illustrate the present invention more
in detail.
EXAMPLES
Example 1
[0046] 0.3 Parts by weight of a spirooxazine dye (PH1 available
from Hodogaya Chemical Co., Ltd.) as a photochromic material, and
15 parts by weight of SEBS (available from Asahi Chemical Industry
Co., Ltd.) and 15 parts by weight of a petroleum resin as base
polymers were combined with a solvent to prepare 100 parts by
weight of a coloring material layer solution. Then, this coloring
material layer solution was coated on a release film having a
release layer of 1 micron using a roll coater and the solvent was
dried off to obtain an intended coloring material layer. The
resulting coloring material layer had a thickness of 50
microns.
[0047] Then, laminating procedures took place by bringing a
polyester deposition film (TEC BARRIER S available from Mitsubishi
Chemical Corp.) of 12 microns in thickness having an SiO2
deposition layer of 500 angstroms into contact with a surface of
said coloring material layer with heating at 100.degree. C.
[0048] Then, said release film was released to bare the other
surface of the coloring material layer, thereafter laminating
procedures took place in the same manner as above by bringing a
deposition film into contact with said other surface of the
coloring material layer with heating at 100.degree. C. to prepare
an intended photochromic film.
[0049] The oxygen permeability and vapor permeability of the
deposition film used in this example vs. temperature change are
shown in Table 1.
[0050] (Evaluation)
[0051] Accelerated weathering test
[0052] The photochromic film obtained as above was left in a
fadeometer and exposed to UV rays. The time by which the absorbance
of said film at 550 nm deteriorated to 50% or less was
determined.
[0053] Here, an absorbance of 50% or less means that the
photochromic film develops or changes color too slightly to
practically have a commercial value.
[0054] The atmosphere in the fadeometer was established under high
temperature and high humidity conditions of 40.degree. C. and a
humidity of 80%.
[0055] (Results)
[0056] The results showed that an absorbance of 50% or more could
be kept for a period as long as 200 hours.
Comparative Example 1
[0057] In Comparative example 1, a photochromic film was prepared
similarly to Example 1 except that the deposition film of Example 1
was replaced by an ethylene resin film (EVOH available from Kuraray
Co., Ltd.) among conventional non-deposition oxygen barrier films,
and evaluated similarly to Example 1.
[0058] (Results)
[0059] The results showed that the absorbance was lowered to less
than 50% in 100 hours.
Examples 2 and 3 and Comparative Examples 2 and 3
[0060] In Example 2, a photochromic film was prepared similarly to
Example 1 except that the deposition layer in the deposition film
of Example 1 was replaced by ITO of 200 angstroms in thickness, and
evaluated similarly to Example 1.
[0061] In Example 3, a photochromic film was prepared similarly to
Example 1 except that the deposition layer in the deposition film
of Example 1 was replaced by aluminium of 150 angstroms in
thickness, and evaluated similarly to Example 1.
[0062] In Comparative example 2, a photochromic film was prepared
similarly to Example 1 except that the deposition film of Example 1
was replaced by a saran resin film of 20 microns in thickness among
conventional non-deposition oxygen barrier films, and evaluated
similarly to Example 1.
[0063] In Comparative example 3, a photochromic film was prepared
similarly to Example 1 except that the deposition film of Example 1
was replaced by a polyester film of 50 microns in thickness, and
evaluated similarly to Example 1.
[0064] The oxygen permeability and vapor permeability of each film
used in Comparative examples 1 and 2 vs. temperature change are
shown in Table 1.
[0065] (Results)
[0066] Examples 2 and 3 kept an absorbance of 50% or more for a
period as long as 200 hours, similarly to Example 1.
[0067] The absorbance declined to less than 50% in 50 hours in
Comparative example 2 and 100 hours in Comparative example 3.
1 TABLE 1 Film for protecting Oxygen permeability.sup.1) Vapor a at
various temperatures permeability coloring (cc/m.sup.2. day. atm)
(40.degree. C., material De- 23.degree. C. 30.degree. C. 42.degree.
C. 90%) layer posit (90%) (71%) (38%) (g/m.sup.2. day ) Example 1
Deposition SiO.sub.2 0.13 0.15 0.47 0.3 film Comp- Ethylene None
1.51 3.52 20.5 2.6 arative resin example 1 film Comp- Saran None
0.60 0.96 2.92 0.9 arative resin example 2 film .sup.1)The value in
parentheses represents the relative humidity at the temperature
indicated.
ADVANTAGES OF THE INVENTION
[0068] The photochromic film according to the present invention,
which comprises a coloring material layer containing a photochromic
material and a phototransmissive deposition film laminated to said
coloring material layer, shows a photochromic activity to develop
or change color in response to UV rays passed through the
deposition film face and absorbed into the photochromic material.
Moreover, the deposition film according to the present invention
can retain the photochromic activity because it does not increase
the oxygen permeability with temperature change.
* * * * *