U.S. patent application number 09/791312 was filed with the patent office on 2001-09-06 for temperature stable and sunlight protected photochromic articles.
Invention is credited to Florent, Frederic Henri, Henry, David, Vachet, Andre Jean, Vial, Jacques Jean.
Application Number | 20010020061 09/791312 |
Document ID | / |
Family ID | 27252995 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010020061 |
Kind Code |
A1 |
Florent, Frederic Henri ; et
al. |
September 6, 2001 |
Temperature stable and sunlight protected photochromic articles
Abstract
The invention relates to photochromic transparent organic
materials particularly useful for the production of photochromic
organic ophthalmic lenses. The material includes an optical-quality
polymer matrix and at least one coloring agent giving photochromic
properties to the matrix. The coloring agent is chosen from the
group of the spirooxazins the spiropyrans, and the chromenes. The
polymer of the matrix is chosen from the group of homopolymers of
ethyoxylated bisphenol A dimethacrylate with formula I: 1 in which
R is H or CH.sub.3, and m and n independently represent 1 or 2, and
of the copolymers of this dimethacrylate containing at most 30 wt %
of an aromatic monomer with vinyl, acrylic or methacrylic
functionality.
Inventors: |
Florent, Frederic Henri;
(Samoreau, FR) ; Henry, David; (Saint-Michel
S/Orge, FR) ; Vachet, Andre Jean; (Montigny S/Loing,
FR) ; Vial, Jacques Jean; (Noisy S/Ecole,
FR) |
Correspondence
Address: |
Angela N. Nwaneri, Esq.
Corning Incorporated
Patent Department
SP-TI-3-1
Corning
NY
14831
US
|
Family ID: |
27252995 |
Appl. No.: |
09/791312 |
Filed: |
February 22, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09791312 |
Feb 22, 2001 |
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09426655 |
Oct 25, 1999 |
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09426655 |
Oct 25, 1999 |
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08817561 |
Apr 21, 1997 |
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5973039 |
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60000829 |
Jul 28, 1995 |
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Current U.S.
Class: |
524/560 ;
524/107; 524/86 |
Current CPC
Class: |
C08F 22/1006 20200201;
C08L 63/10 20130101; C08L 33/14 20130101; C08K 5/1545 20130101;
G02B 1/04 20130101; G02B 1/04 20130101; C08F 20/30 20130101; C08K
5/3412 20130101; C08K 5/3437 20130101; C08K 5/3412 20130101 |
Class at
Publication: |
524/560 ; 524/86;
524/107 |
International
Class: |
C08F 022/12; C08K
005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 12, 1994 |
FR |
94 14933 |
Claims
1. Photochromic transparent organic materials consisting of an
optical quality polymer matrix and at least one coloring agent
giving photochromic properties to said matrix, the coloring agent
being selected from the group consisting of spiroxazines,
spiropyrans, and chromenes; and the polymer of the matrix being
selected from the group consisting of (a) homopolymers of
ethoxylated bisphenol A dimethylacrylate with formula I: 10in which
R is H or CH.sub.3, and m and n independently represent 1 or 2, and
(b) copolymers of ethoxylated bisphenol A dimethylacrylate
containing at most 30 weight percent of an aromatic monomer with
vinyl, acrylic or methoacrylic functionality.
2. Photochromic organic materials according to claim 1,
characterized by the fact that they contain a mixture of
photochromic coloring agents giving a gray or brown tint to the
glass in a darkened state.
3. Photochromic organic materials according to claim 1 wherein the
polymer is a comonomer selected from the group consisting of
divinylbenzene, diallyl phtalate, benzyl methacrylate, benzyl
acrylate, naphthyl methacrylate and naphthyl acrylate.
4. A process for making the photochromic organic material according
to claim 1, comprising the steps of polymerizing a polymer selected
from the group consisting of (a) homopolymers of ethoxylated
bisphenol A dimethylacrylate with formula I: 11in which R is H or
CH.sub.3, and m and n independently represent 1 or 2, and (b)
copolymers of ethoxylated bisphenol A dimethylacrylate containing
at most 30 weight percent of an aromatic monomer with vinyl,
acrylic or methoacrylic functionality, said polymer being
polymerized in the presence of a diazo radical initiator and in the
presence of a peroxide radical initiator.
5. The process according to claim 4, wherein R is H and m=n=2.
6. The process according to claim 5, wherein the polymerization is
carried out in the presence of at least one photochromic coloring
agent selected from the group consisting of spriooxazines,
spiropyrans and chromenes.
7. The process according to claim 4, further comprising the step of
incorporating at least one photochromic coloring agent into the
polymer matrix.
8. The process according to claim 7, wherein the photochromic
coloring agent is incorporated by a process of thermal
diffusion.
9. Photochromic articles comprising the transparent photochromic
organic materials according to claim 1.
10. An ophthalmic lens comprising the transparent photochromic
organic material according to claim 1.
Description
[0001] This application claims the benefit of French Patent No. 94
14933 filed Dec. 12, 1994, and Provisional Application 60/000,829
filed Jul. 28, 1995, titled "Temperature Stable and Sunlight
Protected Photochromic Articles", by Frederic H. Florent, David
Henry, Andre J. Vachet, and Jacques J. Vial.
FIELD OF THE INVENTION
[0002] The invention relates to new photochromic transparent
organic materials with a high refractive index, to a process for
their preparation, and to the articles made of these materials.
BACKGROUND OF THE INVENTION
[0003] It is difficult to find a photochromic material allowing for
the production of an ophthalmic lens whose transmittance varies as
a function of the lighting. Outside of their photochromic
properties (i.e., colorability, rapid darkening and lightening
kinetics, acceptable durability, etc.), such lenses are generally
made by the use of appropriate mixtures of photochromic compounds
such as spirooxazines and chromenes. The polymer matrixes which are
used, though thermally crosslinked, have a low glass transition
point, generally lower than that of CR39.RTM., a reference
ophthalmic resin consisting of diethylene glycol bis(allyl
carbonate) available from PPG Industries, so as to have rapid
photochromic kinetics. Moreover, these polymers generally have a
relatively low refractive index (<1.54).
[0004] The majority of these thermally crosslinked matrixes are
obtained by radical polymerization (i.e., polymerization which most
often can only be carried out provided that one uses initiators of
the organic peroxide type.) The use of organic peroxides makes it
practically impossible to incorporate photochromic molecules in the
mixture of monomers before polymerization, the peroxides having the
effect either of destroying any photochromic effect or of giving
the product an unacceptable permanent intense coloration. Also, one
is obliged to later incorporate coloring agents into the matrix,
most often by a special thermal diffusion process.
[0005] Therefore, there continues to be a need for photochromic
trans-parent organic materials which have improved photochromic
properties and which are easy to manufacture and not very expensive
to manufacture.
SUMMARY OF THE INVENTION
[0006] Briefly, the invention relates to new photo-chrornic
transparent organic materials which are particularly useful for the
production of photochromic organic ophthalmic lenses. The organic
material consists of an optical-quality polymer matrix and at least
one coloring agent giving photochromic properties to the matrix.
The coloring agent is chosen from the group of the spirooxazines,
the spiropyrans, and the chromenes. The polymer of the matrix is
chosen from (a) homopolymers of ethyoxylated bisphenol A
dimethacrylate having formula I: 2
[0007] in which R is H or CH.sub.3, and m and n independently
represent 1 or 2, and (b) copolymers of ethoxylated bisphenol A
dimethacrylate containing, at most, 30 wt % of at least one
aromatic monomer with vinyl, acrylic, or methacrylic
functionality.
[0008] Surprisingly, we have found that the materials of the
invention are characterized particularly by a glass transition
point, and therefore by a hardness, which is greater than that of
many hitherto known organic ophthalmic products without any adverse
effects on the darkening and lightening speeds. We have also found
that, through the choice of an appropriate mixture of several
coloring agents, it is possible to obtain the desired tint in such
matrixes, particularly gray or brown, with this tint practically
not varying in the course of darkening and lightening.
[0009] The inventive organic materials also exhibit a high
refractive index, which is in all cases greater than 1.54, and
which can be adjusted, if necessary, to the desired value by the
use of an appropriate modifying comonomer.
[0010] Useful co-monomers for the invention include vinyl, acrylic
or methacrylic compounds containing in their formula one or more
benzene nuclei. Examples of some useful co-monomers are,
divinylbenzene, diallyl phthalate, benzyl or naphthyl acrylates or
methacrylates, etc., as well as their derivatives substituted on
the aromatic nucleus or nuclei by chlorine or bromine atoms.
[0011] In another aspect, the invention also relates to a process
for the preparation of the photochromic organic materials of the
invention by polymerizing an ethoxylated bisphenol A
dimethacrylate, corresponding to formula I: 3
[0012] in which R is H or CH.sub.3, and m and n independently
represent 1 or 2, optionally with up to 30 wt % of one or more
modifying aromatic monomers with vinyl, acrylic or methacrylic
functionality, in the presence of a diazo radical initiator and in
the absence of a peroxide radical initiator. Preferably, R is H,
and m=n= 2.
[0013] Preferably, the polymerization is carried out in the
presence of at least one photochromic coloring agent, which allows
one to color the final material in its mass.
DETAILED DESCRIPTION OF THE INVENTION
[0014] An essential characteristic of the present process is that
it is implemented in the absence of a peroxide radical initiator,
the latter being replaced by a diazo initiator. This has the
advantage of allowing one to incorporate the photochromic coloring
agent in the resin matrix before polymerization of the matrix.
Polymerization in the presence of the coloring agent cannot be
carried out with a peroxide initiator because the latter may
generate a strong initial coloration of the resulting organic
glass. The peroxide initiator may also lead to a loss of the
photochromic effect. Accordingly, in current processes for the
production of organic glasses, when a peroxide initiator is used, a
separate coloration step is required in order to re-impart
photochromic properties or color back into the glass. As stated
earlier, the coloration is generally done for example, by the
diffusion of the coloring agent or agents into the glass matrix,
usually at elevated temperatures. The preferred inventive process
avoids this additional coloring step, and if desired, allows for
the production of a photochromic lens in a single step by carrying
out the polymerization directly in a lens mold.
[0015] Of course, if desired, the coloring agent can be omitted
from the polymerizable mixture, and the incorporation of the
photochromic coloring agent or agents in the polymerized matrix can
be carried out by a conventional thermal diffusion process as
described for example, in U.S. Pat. Nos. 5,130,353, 5,185,390 and
5,180,254. According to the method described in these references, a
substrate impregnated with photochromic coloring agent or agents is
applied to one surface (usually the convex surface in the case of a
lens) of the polymer matrix. The impregnated substrate is then
heated to 100-150.degree. C. for one to three hours, and finally
the substrate is separated from the polymer matrix.
[0016] The photochromic coloring agent can be chosen from the
general classes of the spirooxazines, spiropyrans and chromenes
having photochromic properties. Quite a large number of
photochromic coloring agents are described in the literature and
are commercially available and are described for example in U.S.
Pat. Nos. 5,246,630 and 4,994,208, both herein incorporated by
reference.
[0017] Examples of useful spirooxazines for the invention are
described in U.S. Pat. Nos. 3,562,172; 4,634,767; 4,637,698;
4,720,547; 4,756,973; 4,785,097; 4,792,224; 4,784,474; 4,851,471;
4,816,584; 4,831,142; 4,909,963; 4,931,219; 4,936,995; 4,986,934;
5,114,621; 5,139,707; 5,233,038; 4,215,010; 4,342,668; 4,699,473;
4,851,530; 4,913,544; 5,171,636; 5,180,524; and 5,166,345, and also
in EP-A 0,508,219; 0,232,295; and 0,171,909, among others, herein
incorporated by reference.
[0018] Examples of chromenes that can be used are described also in
U.S. Pat. Nos. 3,567,605; 4,889,413; 4,931,221; 5,200,116;
5,066,818; 5,244,602; 5,238,981; 5,106,998; 4,980,089; and
5,130,058 and EP-A 0,562,915, all herein incorporated by
reference.
[0019] Useful spiropyrans have been described in the literature,
for example, in Photochromism, G. Brown, Ed., Techniques of
Chemistry, Wiley Interscience, Vol. III, 1971, Chapter III, pp.
45-294, R. C. Bertelson; and Photochromism, Molecules &
Systems, Edited by H. Durr, H. Bouas-Laurent, Elsevier, 1990,
Chapter 8, "Spiropyrans," pp. 314-455, R. Guglielmetti, all herein
incorporated by reference.
[0020] On an indicative and nonlimiting basis, the proportion of
photochromic coloring agent(s) to be incorporated in the matrix can
range from 0.03 to 0.3 wt %, and preferably from 0.05 to 0.1 wt
%.
[0021] Preferably also, one uses a combination of photochromic
coloring agents giving a gray or brown tint in the darkened
state.
[0022] As diazo radical initiator, it is possible to use
azobisisobutyronitrile (AIBN) and
2,2'-azobis(2-methylbutyronitrile), among others. Other examples of
useful diazo radical initiators are also described in "Polymer
Handbook," by Bandrup and Immergut, p. II-2, John Wiley (1989).
[0023] To carry out the polymerization, it is possible, for
example, to heat the polymerizable mixture slowly until the
beginning of thermal degradation of the diazo compound with release
of nitrogen and free radicals. This can occur at a relatively low
temperature which depends on the diazo compound which is used
(approximately 65.degree. C. in the case of AIBN). The
polymerization is carried out for several hours, for example, 10-20
hours. One finally proceeds to anneal the structure by heating in
successive temperature stages, which can exceed 100.degree. C., and
for a duration of approximately 1 hour each.
[0024] The invention finally relates to the articles consisting
completely or partially of a photochromic organic material
according to the invention.
[0025] Nonlimiting examples of such articles are lenses for
ophthalmic (corrective) glasses or sunglasses, windows for
automobiles and other vehicles, windows for buildings, etc. In the
articles of the invention, the photochromic organic material of the
invention can constitute the whole thickness of the article (solid
article) or can be in the form of a film or layer stratified on a
transparent organic or mineral support.
[0026] Lenses, especially ophthalmic lenses, are particularly
preferred articles of the invention.
[0027] These lenses can be produced conveniently by carrying out
the polymerization in lens molds, in a conventional manner, for
example, as described in U.S. Pat. Nos. 2,242,386; 3,136,000; and
3,881,683 which are herein incorporated by reference.
[0028] The stratified articles can be produced easily by
application of the polymerizable mixture (for example, by
immersion, by centrifugation, by brush, etc.) to the support and
polymerization of said mixture in situ.
EXAMPLES
[0029] In order to suitably understand the invention, the following
nonlimiting examples are given. The parts are parts by weight.
Example 1
[0030] (Reference)
[0031] Two non-photochromic organic glasses are prepared by the
following mode of operation:
[0032] A) 100 parts of Diacryl 121 (tetraethoxylated bisphenol A
dimethylmethacrylate (formula I in which R.sub.1= CH.sub.3,
R.sub.2= H and m=n=2) sold by the AKZO Company) is mixed with 0.25
part azobisisobutyronitrile (AIBN) as initiator. The mixture is
polymerized in a lens mold for 16 hours at 65.degree. C. in a
nitrogen atmosphere. The resulting mold is posthardened for 1 hour
at 70.degree. C., for 1 hour at 80.degree. C. and for 1 hour at
110.degree. C. so as to obtain an organic lens after removal from
the mold.
[0033] B) In this second stage, operation A is repeated except that
the Diacryl 121 is replaced by Diacryl 101 (diethoxylated bisphenol
A dimethylmethacrylate (formula I in which R.sub.1= CH.sub.3,
R.sub.2=H, and m=n=1) sold by the AKZO company).
[0034] The physical properties of these glasses, as well as those
of a reference organic glass commercially available under the
registered brand CR39.RTM. and consisting of the homopolymer of
diethylene glycol bis(allyl carbonate), are indicated in Table I
hereafter.
1TABLE I Compared physical properties Glass Derived Glass Derived
CR39 .RTM. From Diacryl 101 From Diacryl 121 Shore D Hardness 84 89
84 Vickers Hardness 215 490 230 (N/mm.sup.2) Elastic Modulus in GPa
by DMA 3.34 5.30 3.40 by Vickers 3.17 5.10 3.34 Glass Transition
94.degree. C. 156.degree. C. 107.degree. C. T.sub.g(max
t.sub.g.delta.) Refractive Index 1.498 1.565 1.5575
n.sub.D.sup.20
[0035] One observes that the polymer materials used in the
invention at the same time have mechanical properties that are
equivalent to or superior to those of CR39.RTM., the reference
product, and a clearly higher refractive index values.
Example 2
[0036] Same process as Examples 1A or 1B, except that a
photochromic coloring agent chosen from the table below is
incorporated into the polymerization mixture. The coloring agent is
dissolved in the monomer with stirring and slight heating.
2 Coloring Agents COLORING AGENT NO. FORMULA NOMENCLATURE 1 4
1,3,3-Trimethylspiro [2H-indole-2,3'-[3H] phenanthra(9,10b)[1,4]
oxazine] 2 5 5-Chloro derivative of coloring agent No. 1 3 6
1,3,3-Trimethylspiro [indolino-2,3'[3H]-naphtho (2,1b)(1,4)oxazine]
4 7 1,3,3,5,6-Pentamethylspiro [indolino-2,3'[3H]-naphtho
(2,1b)(1,4)oxazine] 5 8 1,3,3-Trimethylspiro
[indolino-6'-(1-piperidyl)- 2,3'[3H]-napththo (2,1b)(1,4)oxazine] 6
9 3,3-Diphenyl-3H-naththo [2,1b]pyrane
[0037] In the photochromic materials or glasses obtained, the times
of half-darkening and half-lightening are measured. The light
source is a mercury vapor lamp, and the measurement of transmission
is done at the wavelength of .lambda..sub.max of the coloring agent
and at room temperature on a 2-mm-thick sample. Table II below
recapitulates the results various photochromic materials according
to the invention.
3TABLE II t.sub.1/2 t.sub.1/2 Darken- Light- Photo- Color- ing ning
chromic ing .lambda..sub.max Concen- (sec- (sec- Glass Matrix Tg
Agent (nm) tration onds) onds) 1 Diacryl 156.degree. C. 3 605 0.3%
3 4 101 2 Diacryl -- 6 435 0.4% 4 7 101 3 Diacryl -- 1 605 0.05% 5
7 101 4 Diacryl -- 2 590 0.05% 7 11 101 5 Diacryl 109.degree. C. 3
605 0.3% 3 4 122 6 Diacryl -- 4 605 0.2% 3 6 121
[0038] The examples above show that, regardless of the type of
photochromic compound used, one observes with all the glasses of
the invention rapid kinetics of darkening as well as lightening, in
spite of the high T.sub.S values of the resins, particularly in the
case of Diacryl 101 (T.sub.g=156.degree. C.), with the best mode
being represented by photochromic glass 1.
Example 3
[0039] A photochromic lens with a gray tint is prepared according
to the mode of operation of Example 1A, except that one
incorporates in the polymerization mixture 0.2 part No. 4 blue
coloring agent, 0.025 part No. 5 red coloring agent and 0.20 part
No. 6 yellow coloring agent.
[0040] The lens obtained has rapid darkening and lightening
properties. The kinetics of the three coloring agents used being
similar, the lens keeps its neutral gray tint during the process of
darkening, as well as that of lightening. The lens has a good
photostability with time as shown by the results presented in Table
III below, of transmittance measurements before and after 283 hours
of exposure at a wavelength of 560 nm (60,000-lux xenon lamp) at
20.degree. C.
4 TABLE III Transmittance Before After T.sub.O.sup.910 84.9% 82.5%
T.sub.D15.sup.(2) 26.5% 28.1% T.sub.F5.sup.(3) 72.7% 71.6% T.sub.O
corresponds to the initial transmission of the lens. T.sub.D15 = %
transmission at 560 nm after 15 min of exposure under the xenon
lamp; thickness of sample: 2 mm. T.sub.F5 = % transmission at 560
nm after 15 min of exposure and 5 min of lightening in
darkness.
Example 4
[0041] This example illustrates the variant of the process of the
invention consisting of incorporating the photochromic coloring
agent by diffusion after polymerization.
[0042] One prepares a lens according to the mode of operation of
Example 1, and therefore not containing any photochromic coloring
agents.
[0043] One prepares a solution of 1 g of coloring agent No. 4 in 10
g of tetrahydrofuran. One impregnates a disk of filter paper with
the solution thus prepared; one applies the filter to the convex
front surface of the lens obtained. One maintains the lens under
pressure by means of a mineral glass lens with the same radius of
curvature as the plastic lens, and one heats it for 2 hours at
130.degree. C. One separates the components, and stoves the lens
obtained for 2 hours at 110.degree. C.
[0044] The final lens obtained is photochromic with the following
characteristics (measured at .lambda..sub.max=616 nm).
[0045] Initial transmission T.sub.o= 86.6%
[0046] Transmission in the darkened state= 13.8%
[0047] Half-darkening time t.sub.1/2=3 sec
[0048] Half-lightening time t.sub.1/2= 4 sec
[0049] The results obtained (kinetics) are completely comparable to
those obtained by incorporation in the matrix beforehand (see
Example 2).
[0050] It goes without saying that the embodiments described are
only examples, and one could modify them, particularly by
substitution of equivalent techniques, without consequently leaving
the scope of the invention.
* * * * *