U.S. patent application number 12/398885 was filed with the patent office on 2009-10-01 for dyeing method for plastic lens.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Yuko IMAI, Toru SAITO, Naoki UCHIDA.
Application Number | 20090241273 12/398885 |
Document ID | / |
Family ID | 40875188 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090241273 |
Kind Code |
A1 |
SAITO; Toru ; et
al. |
October 1, 2009 |
Dyeing Method for Plastic Lens
Abstract
A dyeing method for a plastic lens includes immersing the
plastic lens in an oil bath containing a dye.
Inventors: |
SAITO; Toru; (Minowamachi,
JP) ; UCHIDA; Naoki; (Minowamachi, JP) ; IMAI;
Yuko; (Suwashi, JP) |
Correspondence
Address: |
HOGAN & HARTSON L.L.P.
1999 AVENUE OF THE STARS, SUITE 1400
LOS ANGELES
CA
90067
US
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
40875188 |
Appl. No.: |
12/398885 |
Filed: |
March 5, 2009 |
Current U.S.
Class: |
8/506 |
Current CPC
Class: |
D06P 1/92 20130101; D06P
1/908 20130101; D06P 1/928 20130101; B29D 11/00903 20130101 |
Class at
Publication: |
8/506 |
International
Class: |
D06P 3/00 20060101
D06P003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2008 |
JP |
2008-080697 |
Claims
1. A dyeing method for a plastic lens, comprising: immersing the
plastic lens in an oil bath containing a dye.
2. The dyeing method for a plastic lens according to claim 1,
wherein the plastic lens is made of an episulfide material.
3. The dyeing method for a plastic lens according to claim 1,
wherein the plastic lens has a single layered or multilayered hard
coat layer.
4. The dyeing method for a plastic lens according to claim 3,
wherein the hard coat layer contains the following (A) and (B); (A)
a fine inorganic oxide particle, and (B) an organosilicon compound
as represented by the following formula (1),
R.sup.1R.sup.2.sub.nSiX.sup.1.sub.3-n (1) (where R.sup.1 is an
organic group having a polymerizable reactive group, R.sup.2 is a
hydrocarbon group having 1 to 6 carbon atoms, X.sup.1 is a
hydrolyzable group, and n is 0 or 1).
5. The dyeing method for a plastic lens according to claim 1,
wherein the dye is a solvent dye.
6. The dyeing method for a plastic lens according to claim 1,
wherein a temperature of the oil bath is 100 degrees C. or more
when the plastic lens is immersed.
7. The dyeing method for a plastic lens according to claim 1,
wherein oil used for the oil bath is silicone oil.
8. The dyeing method for a plastic lens according to claim 2,
wherein the dye is a solvent dye.
9. The dyeing method for a plastic lens according to claim 2,
wherein a temperature of the oil bath is 100 degrees C. or more
when the plastic lens is immersed.
10. The dyeing method for a plastic lens according to claim 2,
wherein oil used for the oil bath is silicone oil.
11. The dyeing method for a plastic lens according to claim 3,
wherein the dye is a solvent dye.
12. The dyeing method for a plastic lens according to claim 3,
wherein a temperature of the oil bath is 100 degrees C. or more
when the plastic lens is immersed.
13. The dyeing method for a plastic lens according to claim 3,
wherein oil used for the oil bath is silicone oil.
14. The dyeing method for a plastic lens according to claim 4,
wherein the dye is a solvent dye.
15. The dyeing method for a plastic lens according to claim 4,
wherein a temperature of the oil bath is 100 degrees C. or more
when the plastic lens is immersed.
16. The dyeing method for a plastic lens according to claim 4,
wherein oil used for the oil bath is silicone oil.
Description
[0001] The entire disclosure of Japanese Patent Application No.
2008-080697, filed Mar. 26, 2008 is expressly incorporated by
reference herein.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention is related to a dyeing method for a
plastic lens.
[0004] 2. Related Art
[0005] There have been various known dyeing methods for a plastic
lens such as a spectacle lens. The known dyeing methods include a
method in which a lens base material is directly dyed and a method
in which a to-be-dyed layer formed on a lens base material is
dyed.
[0006] Specifically, a water-based dyeing pot in which a disperse
dye and, as needed, a surfactant and a dye carrier are added is put
in hot water of approximately 90 degrees C. Subsequently, a lens
base material is immersed in the dyeing pot while the mixture is
agitated so as to directly dye the lens base material (for example,
Document 1: JP-A-10-259580, Document 2: JP-A-6-313801, Document 3:
JP-A-6-347602).
[0007] Alternatively, a lens base material may be provided with a
hard coat layer capable of being dyed in hot water, and then
immersed in the above-described dyeing pot to be dyed.
[0008] In recent years, a plastic lens has been thinned, and a
material with a high refractive index has been developed and
commercialized. For example, a thiourethane resin is typically used
as a material having a refractive index n of 1.69 or less, and an
episulfide resin is typically used as a material having a
refractive index n of 1.70 or more.
[0009] The thiourethane resin has appropriate water-absorptivity.
Thus, a plastic lens made of the thiourethane resin can be easily
dyed by being dipped in a water-based dyeing pot. On the other
hand, the episulfide resin has extremely low water-absorptivity.
Thus, a plastic lens made of the episulfide resin can be hardly
dyed by being dipped in a water-based dyeing pot. Even after the
plastic lens is immersed for a long time, the plastic lens cannot
be strongly dyed.
[0010] To enhance a dyeing speed, a temperature of a dyeing pot is
typically raised. However, it is difficult that a temperature of a
water-based dyeing pot is raised over 100 degrees C. To raise the
temperature of the dyeing pot to 100 degrees C. or more, the dyeing
pot can be entirely covered with a pressure container or the like
and hermetically-closed. However, an apparatus of large size may be
required, and dyeing tone may not be checked during a dyeing
process.
[0011] Also, since it is required that the water-based dyeing pot
is heated to approximately 90 degrees C., water, a dye carrier and
the like may be vaporized and dyeing property may be changed.
[0012] Further, when a plastic lens on which a hard coat layer is
formed is dyed, a chemical compound having high water absorption
needs to be added since a material used for forming the hard coat
layer is typically difficult to be dyed. Consequently, hardness of
the hard coat layer may be lowered and abrasion resistance may be
deteriorated.
SUMMARY
[0013] Exemplary aspects of the invention provide a dyeing method
capable of dyeing a plastic lens for a short time.
[0014] A dyeing method for a plastic lens according to an aspect of
the invention includes immersing the plastic lens in an oil bath
containing a dye.
[0015] An oil-based dyeing pot is used according to the exemplary
aspect of the invention, so that dye-affinity of the plastic lens
made of a material having low water absorption can be enhanced.
Thus, dyeing time can be shortened.
[0016] Also, because a temperature of the oil-based dyeing pot can
be raised to a high temperature, for instance, 100 degrees C. or
more, the dye-affinity can be further enhanced. Thus, the dyeing
time for the plastic lens can be considerably shortened, which
leads to excellent manufacturing efficiency.
[0017] Further, because a surface of the plastic lens can be
uniformly dyed even when being dyed at a high temperature, quality
of the plastic lens can be maintained.
[0018] Furthermore, because oil is not easily volatilized, the
change of dyeing property of the dyeing pot can be prevented even
after elapse of time.
[0019] According to the exemplary aspect of the invention, the
plastic lens may be made of an episulfide material.
[0020] Since the episulfide material has low water absorption and
high lipophilicity, the episulfide resin lens base material is not
easily dyed in a water-based dyeing pot even after being dyed for a
long time.
[0021] However, because the oil-based dyeing pot is used according
to the exemplary aspect of the invention, the episulfide resin lens
base material can be easily dyed and dyeing time can be
considerably shortened. Thus, excellent manufacturing efficiency
can be exhibited because the dyeing time for the episulfide resin
lens base material can be considerably reduced.
[0022] According to the exemplary aspect of the invention, the
plastic lens may have a single layered or multilayered hard coat
layer.
[0023] The hard coat layer typically has low water absorption and
high lipophilicity.
[0024] Since the oil-based dyeing pot is used according to the
exemplary aspect of the invention, the hard coat layer can be
easily dyed. Consequently, dyeing time for the lens base material
on which the hard coat layer is formed can be considerably
reduced.
[0025] Additionally, a compound having high water absorption, which
is conventionally added to make the hard coat layer dyeable, does
not need to be added at this time. Consequently, an original
hardness of the hard coat layer can be maintained, and therefore a
dyed lens having high abrasion-resistance can be obtained.
[0026] In the dyeing method for a plastic lens according to the
exemplary aspect of the invention, the hard coat layer may contain
the following (A) and (B); [0027] (A) a fine inorganic oxide
particle, and [0028] (B) an organosilicon compound represented by
the following formula (1),
[0028] R.sup.1R.sup.2.sub.nSiX.sup.1.sub.3-n (1)
[0029] In the formula, R.sup.1 is the organic group having the
polymerizable reactive group, R.sup.2 is a hydrocarbon group having
1 to 6 carbon atoms, X.sup.1 is a hydrolyzable group, and n is 0 or
1.
[0030] The component (A) may be a fine inorganic oxide particle
having an average size of 1 to 200 nm and containing a composite
oxide having a rutile-type crystal structure formed of titanium
oxide and tin oxide, or titanium oxide, tin oxide and silicon
oxide. For the purpose of preventing interference fringes, the hard
coat layer is required to have a high refractive index. In order to
provide the hard coat layer with a high refractive index, a method
using fine inorganic oxide particle with a high refractive index is
typically employed. Specifically, an oxide of one or more of metals
selected from Al, Sn, Sb, Ta, CE, La, FE, Zn, W, Zr, In and Ti
(including mixture thereof) and/or transparent fine inorganic oxide
particle formed of a composite oxide containing two or more metals.
Among these, a fine inorganic oxide particle containing titanium
oxide is typically used in terms of refractive index, transparency,
dispersion stability and the like.
[0031] An organosilicon compound as the component (B) is a
so-called silane coupling agent, which serves as a binder resin of
the hard coat layer. The compound represented by the formula (1) is
preferably used because the compound serves as a strong binder
resin of the fine inorganic oxide particle in the hard coat
layer.
[0032] In the dyeing method for a plastic lens according to the
exemplary aspect of the invention, the dye may be a solvent
dye.
[0033] According to the exemplary aspect of the invention, dyeing
agent is prepared by adding the solvent dye in the oil-based dyeing
pot.
[0034] Since the solvent dye is easily dissolved in the oil, the
solvent dye can be uniformly dissolved in the oil and sufficiently
serve as the dye.
[0035] The lens base material or the hard coat layer, which is
conventionally not easily dyed in a water-based pot, typically has
low water absorption and high lipophilicity. The solvent dye is
easily absorbed into the lens base material or the hard coat layer
having high lipophilicity, which improves dye-affinity. Thus,
dyeing time can be shortened.
[0036] In the dyeing method for a plastic lens according to the
exemplary aspect of the invention, a temperature of the oil bath is
100 degrees C. or more when the plastic lens is immersed.
[0037] According to the exemplary aspect of the invention, the
temperature of the oil-based dyeing pot is set to 100 degrees C. or
more for dyeing. In other words, since the oil-based dyeing pot is
used, the temperature can be set to 100 degrees C. or more. As the
temperature is higher, the dye-affinity of the lens base material
can be further enhanced.
[0038] Since the lens base material can be dyed at a higher
temperature, dyeing time for the lens base material can be
considerably reduced.
[0039] In the dyeing method for plastic lens according to the
exemplary aspect of the invention, oil used for the oil bath may be
silicone oil.
[0040] The oil used in the dyeing pot may be vegetable oil, mineral
oil, and synthetic oil. Among the above, the silicone oil exhibits
excellent heat resistance and viscosity stability.
[0041] Thus, by using the silicone oil, the temperature of the
dyeing pot can be set higher and the dyeing time can be further
reduced. Additionally, deterioration of the oil due to high
temperature can be efficiently suppressed, and the dye-affinity of
the dyeing pot can be stabilized for a long time.
DESCRIPTION OF EXEMPLARY EMBODIMENT(S)
[0042] An exemplary embodiment of the invention will be described
below. A plastic lens for spectacles will be exemplarily described
as a lens to be dyed by a method of dyeing a plastic lens according
to this exemplary embodiment.
Arrangement of Lens
[0043] A lens has a hard coat layer formed on a surface of a lens
base material. The lens may also have a primer layer formed between
the hard coat layer and the lens base material.
Arrangement of Lens Base Material
[0044] The lens base material is not particularly limited, but is
preferably a transparent plastic material having a refractive index
of 1.6 or higher in terms of weight reduction of the lens. Examples
of such lens base material may include: a thiourethane plastic made
by reacting a compound having an isocyanate group or an
isothiocyanate group with a compound having a mercapto group; and
an episulfide plastic made by polymerization-curing a material
monomer containing a compound having an episulfide group.
[0045] As the compound having an isocyanate group or an
isothiocyanate group, which is a main component of the thiourethane
plastic, known compounds can be used without any limination.
[0046] Examples of the compound having an isocyanate group may
include ethylene diisocyanate, trimethylene diisocyanate,
2,4,4-trimethylhexane diisocyanate, hexamethylene diisocyanate, and
m-xylylene diisocyanate.
[0047] Also, as for the compound having a mercapto group, known
compounds can be used. Examples of the compound having a mercapto
group may include: an aliphatic polythiol such as
1,2-ethanedithiol, 1,6-hexanediol and 1,1-cyclohexanedithiol; and
an aromatic polythiol such as 1,2-dimercapto benzene and
1,2,3-tris(mercaptomethyl)benzene. In order to provide the plastic
lens with a high refractive index, a polythiol containing a sulfur
atom in addition to a mercapto group may be preferably used,
examples of which may include 1,2-bis(mercaptomethylthio)benzene,
1,2,3-tris(mercaptoethylthio)benzene and
1,2-bis((2-mercaptoethyl)thio)-3-mercaptopropane.
[0048] As the compound having an episulfide group and used as the
material monomer for the episulfide plastic, known compounds having
an episulfide group can be used without any limitation. An example
of such a compound is an episulfide compound that is obtained by
substituting a part or all of oxygen of an epoxy group contained in
an existing epoxy compound with sulfur. In order to provide the
plastic lens with a high refractive index, a compound containing a
sulfur atom in addition to an episulfide group may be preferably
used. Examples of such a compound may include
1,2-bis(beta-epithiopropylthio)ethane,
bis(beta-epithiopropyl)sulfide,
1,4-bis(beta-epithiopropylthiomethyl)benzene, and
2,5-bisebeta-epithiopropylthiomethyl)-1,4-dithiane, and
bis(beta-epithiopropyl)disulfide.
[0049] When a thiourethane plastic lens or an episulfide plastic
lens is polymerized, one or more of the above-described material
monomers are weighed and mixed. As needed, a compound having
another functional group reactable with the material monomers may
be added. Further, an ultraviolet absorber, an antioxidant, an
internal mold release agent, a bluing agent or the like may be
added as necessary. Furthermore, a polymerization catalyst or the
like may be added and mixed to be uniform, so that a polymerizable
composition for a plastic lens is prepared.
[0050] The polymerizable composition prepared as described above is
injected into a void surrounded by a glass mold or the like, and
then the void is hermetically-closed. Subsequently, the
polymerizable composition is heated in a hot-air oven, which is
initially set to 10 to 30 degrees C. and then gradually raised to
100 to 150 degrees C. for 10 to 100 hours, so as to complete
polymerization. Then, the polymerizable composition is cooled to
ambient temperature and a plastic lens is released from the glass
mold or the like. In this manner, various plastic lens can be
manufactured. After such polymerization, the plastic lens may be
subjected to an annealing treatment at 80 to 130 degrees C. for
approximately 10 minutes to 5 hours as necessary in order to
relieve internal stress.
[0051] Such materials having high refractive index are typically
difficult to be dyed. Especially, an episulfide lens base material
is hardly dyed. However, according to the exemplary aspect of the
invention, such materials can be favorably used as a lens base
material for a color lens because the materials are dyed in an
oil-based dyeing pot as described later.
Arrangement of Hard Coat Layer
[0052] A composition used for a hard coat layer is not particularly
limited, and known compositions can be used therefor. For example,
the composition may contain a fine inorganic oxide particle
containing titanium oxide having a rutile-type crystal structure
with an organosilicon compound represented by the following formula
(1) being used as a binder.
R.sup.1R.sup.2.sub.nSiX.sup.1.sub.3-n (1)
[0053] In the formula, R.sup.1 is an organic group having a
polymerizable reactive group, R.sup.2 is a hydrocarbon group having
1 to 6 carbon atoms, X.sup.1 is a hydrolyzable group, and n is 0 or
1.
[0054] Specifically, R.sup.1 has a polymerizable reactive group
such as a vinyl group, an allyl group, an acryl group, a methacryl
group, a 1-methylvinyl group, an epoxy group, a mercapto group, a
cyano group, an isocyano group and an amino group. X.sup.1 is a
hydrolyzable functional group, examples of which may be an alkoxy
group such as a methoxy group, an ethoxy group and a methoxyethoxy
group, a halogen group such as a chloro group and a bromo group,
and an acyloxy group.
[0055] Examples of the organosilicon compound represented by the
formula (1) may include vinyltrialkoxysilane, vinyltrichlorosilane,
vinyltri(beta-methoxy-ethoxy)silane, allyltrialkoxysilane,
acryloxypropyltrialkoxysilane, methacryloxypropyltrialkoxysilane,
gamma-glycidoxypropyltrialkoxysilane,
beta-(3,4-epoxycyclohexyl)-ethyltrialkoxysilane,
mercaptopropyltrialkoxysilane, and
gamma-aminopropyltrialkoxysilane.
[0056] Two or more of the organosilicon compounds may be mixed in
use.
[0057] The fine inorganic oxide particle may contain only titanium
oxide or may contain titanium oxide and other inorganic oxides. For
example, oxides of metals such as Si, Al, Sn, Sb, Ta, Ce, La, Fe,
Zn, W, Zr and In may be mixed with titanium oxide. Further, the
fine inorganic oxide particle may be a composite particle of
titanium oxide and other inorganic oxides. When the composite
particle is used, for example, oxides of metal such as Si, Al, Sn,
Sb, Ta, Ce, La, Fe, Zn, W, Zr and In may be combined with titanium
oxide.
[0058] Furthermore, a curing catalyst such as perchlorates or metal
acetylacetonates may be added to the hard coat layer as
necessary.
[0059] Examples of the curing catalyst may include: perchloric
acids such as a perchloric acid, an ammonium perchlorate and a
magnesium perchlorate; an acetylacetonato having, as a central
metal atom, Cu(II), Zn(II), Co(II), Ni(II), Be(II), Ce(III),
Ta(III), Ti(Ill), Mn(III), La(III), Cr(III), V(III), Co(III),
Fe(III), Al(III), Ce(IV), Zr(IV), V(IV) or the like; an amine; an
amino acid such as a glycine; a Lewis acid; and a metal salt of an
organic acid.
[0060] A coating composition containing the above components may be
diluted with a solvent as needed for use. The solvent may be
alcohols, esters, ketones, ethers, aromatics or the like. The
coating composition may be added with a small amount of an additive
as needed in order to improve coating property of the coating
composition, curing speed and film performance after curing.
Examples of the additive include a metal chelate compound, a
surfactant, an antistatic agent, an ultraviolet absorber, an
antioxidant, a disperse dye, a solvent dye, a pigment, a
photochromic compound, a light/thermal stabilizer such as a
hindered amine and a hindered phenol.
[0061] As for a coating/curing method of the coating composition,
the coating composition is coated by dipping, spin coating, spray
coating, roll coating or flow coating, and then heated and dried at
40 to 200 degrees C. for several hours so as to form a film. The
thickness of the hard coat layer is preferably 0.05 to 30 .mu.m.
When the thickness is below 0.05 .mu.m, basic performance of the
hard coat layer cannot be obtained. On the other hand, when the
thickness exceeds 30 .mu.m, smoothness of the surface may be
degraded or optical distortion may be caused. Incidentally, a
refractive index of the hard coat layer preferably corresponds to
that of the base material and that of the primer layer in order to
prevent interference fringes.
Preparation of Dyeing Agent
[0062] Next, preparation of dyeing agent will be described
below.
[0063] A dye and oil as medium are used in preparing the dyeing
agent.
[0064] The dye is not particularly limited, but may be a solvent
dye and a disperse dye. The solvent dye is preferably used in terms
of a dyeing process in an oil bath.
[0065] Examples of the solvent dye may include various dyes such as
anthraquinone-type dyes, monoazo-type dyes, or heterocyclic-type
dyes. More specifically, examples of the solvent dye may include
"Diaresin Blue J (C.I.Solvent Blue 33)" (trade name), "Diaresin
Blue G (C.I.Solvent Blue 90)" (trade name), "Diaresin Blue N
(C.I.Solvent Blue 94)" (trade name), "Diaresin Green C (C.I.Solvent
Green 26)" (trade name), "Diaresin Red A (C.I.Solvent Red 179)"
(trade name), "Diaresin Red S (C.I.Solvent Red 152)" (trade name),
"Diaresin Violet A (C.I.Solvent Violet 32)" (trade name), "Diaresin
Yellow F (C.I.Solvent Yellow 104)" (trade name), "Diaresin Orange G
(C.I.Solvent Orange 68)" (trade name) (all produced by Mitsubishi
Chemical Industries, Ltd.), "OIL BLUE613 (C.I.Solvent Blue 5)"
(trade name), "OIL BLUE630 (C.I.Solvent Blue 36)" (trade name) (all
produced by Orient Chemical Industries, Ltd.). The above dyes may
be used alone or in combination depending on a desired color.
[0066] According to the exemplary aspect of the invention, the
total amount of the dye added to the oil is preferably in a range
of 0.01 to 50 g per 1 liter of oil for use. When the dye is below
0.01 g, the lens may not be dyed with a desired color because the
total amount thereof is too small. On the other hand, when the dye
exceeds 50 g, the lens may not be uniformly dyed.
[0067] The oil is not particularly limited, but may be vegetable
oil, mineral oil, and synthetic oil. Especially, silicone oil is
preferably used in terms of heat resistance, viscosity stability or
the like.
[0068] Examples of the silicone oil are dimethyl silicone oil and
modified silicone oil. The silicone oil may be suitably selected in
terms of heat resistance and viscosity. Example of such silicone
oil may include "TSF451-20" (trade name), "TSF451-30" (trade name)
(both produced by Toshiba Silicone Co., Ltd.), "KF965-1-100" (trade
name), "KF968-1-100" (trade name) (both produced by Shin-Etsu
Chemical Co., Ltd.).
[0069] A dye carrier agent may be added to the dyeing agent.
[0070] Examples of the dye carrier agent may include alcohols
having aromatic ring such as benzyl alcohol or phenethyl alcohol,
and phenylphenols such as p-phenylphenol, o-phenylphenol and
m-phenylphenol.
[0071] An additive amount of the dye carrier agent is in a range of
0.1 mass % or more and 5 mass % or less relative to the oil in the
dyebath. When the additive amount of the dye carrier agent is less
than 0.1 mass %, concentration of the dye carrier agent is too low.
Thus, the dye carrier does not function well, which lowers
dye-affinity. On the other hand, when the additive amount of the
dye carrier agent exceeds 5 mass %, the lens may not be uniformly
dyed.
[0072] Further, various additive agents such as an antioxidant, an
antifoamer or a surfactant may be added as necessary.
Dyeing Method
[0073] 1 liter of silicone oil and 5 g of "Diaresin Blue J" (trade
name, produced by Mitsubishi Chemical Industries, Ltd.) as a
solvent dye are put in an oil bath, and the temperature of the oil
bath is set to 100 degrees C. While being kept heated, the oil and
the dye are sufficiently agitated until the temperature of the oil
bath is stabilized so as to prepare dyeing agent.
[0074] Subsequently, the temperature of the oil bath is set to 120
degrees C. just before dyeing is started. After the temperature is
stabilized, an episulfide lens base material is completely immersed
in the dying agent in the oil bath. In 10 minutes, the lens base
material is taken out of the oil bath so as to prepare a dyed
lens.
[0075] The following advantages can be attained according to the
exemplary embodiment. [0076] (1) The oil-based dyeing agent is
prepared according to the exemplary embodiment.
[0077] Thus, the dyeing agent can be heated to a high temperature,
for example, over 100 degrees C. Since a lens base material is
typically dyed easily at a high temperature, dyeing time for the
lens base material can be considerably reduced. [0078] (2) The
solvent dye is used in the oil-based dying agent.
[0079] Since the hard coat layer has high lipophilicity, the lens
can be easily dyed with the solvent dye. Additionally, the use of
the oil-based dye agent allows the dye agent to be heated to a high
temperature. Thus, the dyeing time can be further reduced. [0080]
(3) Since the episulfide lens base material, which is difficult to
be dyed in the water-based dying agent, has lipophilicity, the
material can be easily dyed with the solvent dye. Thus, dyeing time
for the episulfide lens base material can be considerably reduced,
which is highly advantageous. [0081] (4) The hard coat layer is
formed of the composition containing a fine inorganic oxide
particle (A) and an organosilicon compound (B).
[0082] Thus, the lens base material on which the hard coat layer
containing the components (A) and (B) is formed has high hardness
and abrasion resistance. [0083] (5) Silicone oil is used as oil in
the dyeing pot. Since the silicone oil has excellent heat
resistance and stable viscosity, stable dyeing property can be
maintained even at a high temperature.
Modifications of Exemplary Embodiment
[0084] The scope of the invention is not limited to the above
exemplary embodiment, but includes modifications and improvements
as long as an object of the invention can be achieved.
[0085] For example, though the lens base material having the hard
coat layer formed on a surface thereof is used according to the
exemplary embodiment, the lens base material that does not have the
hard coat layer can be directly dyed.
[0086] Especially, since a lens base material made of episulfide
resin has high lipophilicity, the dyeing time can be considerably
reduced.
[0087] Incidentally, since the temperature of the dyeing pot can be
set high (over 100 degrees C.) even when the lens base material
made of episulfide resin is used, the dyeing time can be
reduced.
[0088] Though the hard coat layer is directly formed on the lens
base material according to the exemplary embodiment, the primer
layer may be formed on the lens base material to improve adhesion
between the lens base material and the hard coat layer and improve
impact resistance.
[0089] The primer layer preferably contains, for instance, an
organic resin polymer having a polar group and a fine metal oxide
particle such as titanium oxide, zirconium oxide, tin oxide, and
silicon oxide.
[0090] As the organic resin polymer having the polar group, various
resins such as a polyester resin, a polyurethane resin, an epoxy
resin, a melamine resin, a polyolefin resin, a urethane acrylate
resin, and an epoxy acrylate resin are usable. Among these, a
polyester resin is particularly preferable for use in terms of
adherence to the lens base material containing a sulfur atom and
dispersibility of fine metal oxide particles as a filler.
[0091] Further, though the solvent dye is used in the exemplary
embodiment, a water soluble dye may be used. However, additives
such as a surfactant need to be added at this time.
EXAMPLES
[0092] The invention will be described in further detail by
exemplifying Examples and Comparatives. However, the invention is
not limited to Examples.
[0093] Lens base materials (L1, L2) were initially prepared as
described below. Additionally, lens base materials (L3, L4) with
hard coat layers were prepared by forming hard coat layers on a
surface of the obtained lens base materials.
[0094] Subsequently, a dyebath as shown in Examples 1 to 10 and
Comparatives 1 to 7 was prepared, and the lens base material with
the hard coat layer was immersed in the dyebath for dyeing. Then,
dye-affinity was evaluated.
1. Preparation of Lens Base Material L1
(1-1) Preparation of Material Monomer
[0095] As a material monomer, 90 parts by mass of
bis(2,3-epithiopropyl)disulfide, 10 parts by mass of a compound
prepared by mixing one, two, or three of
4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane,
4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 1.0
parts by mass of an ultraviolet absorber ("SEESORB701 " produced by
SHIPRO KASEI KAISHA, LTD.) were put in a glass container provided
with a stirring bar, and stirred sufficiently to be completely
dissolved. Subsequently, 0.02 parts by mass of
N,N-dimethylcyclohexylamine and 0.10 parts by mass of
N,N-dicyclohexylmethylamine were added in this mixture as a
catalyst, and stirred at 20 degrees C. to be uniform.
(1-2) Cast Polymerization
[0096] The mixture (monomer) prepared as described in (1-1) was
injected into a lens mold formed by holding two glass molds facing
each other with a sealing tape. The lens mold was heated by a
hot-air furnace of which the temperature was raised from 30 to 130
degrees C. for 20 hours. After being kept heated at 130 degrees C.
for 2 hours, the lens mold was left to be cooled to 70 degrees C.
for 2 hours. Then, the polymer was released from the lens mold so
as to obtain an episulfide resin lens base material L1. A
refractive index of the lens base material L1 measured by an Abbe
refractometer was 1.74.
2. Preparation of Lens Base Material L2
(2-1) Preparation of Material Monomer
[0097] 50.6 parts by mass of M-xylylene diisocyanate, 49.4 parts by
mass of a compound prepared by mixing one, two, or three of
4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane,
4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1.2
parts by mass of an ultraviolet absorber ("SEESORB701" produced by
SHIPRO KASEI KAISHA, LTD.), and 0.1 parts by mass of an internal
mold release agent ("Zelec UN" produced by Stepan Company) were put
in a glass container provided with a stirring bar, sufficiently
stirred and mixed to be uniformly dispersed and dissolved.
Subsequently, 0.005 parts by mass of dibutyltin dichloride and
0.005 parts by mass of N,N-dimethylcyclohexylamine were added in
this mixture. After being sufficiently stirred to be dissolved at
30 degrees C., the mixture was depressurized to 5 mmHg and
deaerated for 30 minutes while being stirred.
(2-2) Cast Polymerization
[0098] The mixture (monomer) prepared as described in (2-1) was
injected into a lens mold formed by holding two glass molds facing
each other with a sealing tape. The lens mold was heated by a
hot-air furnace of which the temperature was raised from 30 to 120
degrees C. for 20 hours. After being heated at 120 degrees C. for
0.5 hours, the lens mold was left to be cooled to 70 degrees C. for
2 hours. Then, the polymer was released from the lens mold so as to
obtain a thiourethane resin lens base material L2. A refractive
index of the lens base material L2 measured by an Abbe
refractometer was 1.67.
3. Preparation of Lens Base Material L3 with Hard Coat Layer
(3-1 ) Preparation of Composition for Primer Layer and Formation of
Primer Layer
[0099] 100 parts by mass of a commercially available polyester
resin "Pesresin A-160P" (trade name, produced by TAKAMATSU OIL
& FAT CO., LTD, water-dispersible emulsion, solid concentration
of 25%) was mixed with 84 parts by mass of a titanium oxide
composite particle "Optolake 1130F-2(A-8)" (trade name, produced by
Catalyst & Chemicals Co., Ltd, Fe.sub.2O.sub.3/TiO.sub.2=0.02,
SiO.sub.2/TiO.sub.2=0.11, solid concentration of 30%, methyl
alcohol as a dispersible solvent, tetraethoxysilane for surface
finishing), 640 parts by mass of methyl alcohol as a diluting
solvent, 1 part by mass of a silicone-based surfactant "SILWET
L-77" (trade name, produced by Nippon Unicar Company Limited) as a
leveling agent, and then stirred for 3 hours so as to prepare a
composition for a primer layer.
[0100] Then, the lens base material L1 was coated with the
composition for the primer layer by dipping (pull speed 20 cm/min),
and the coated lens was subjected to thermal curing treatment at
100 degrees C. for 15 minutes to form the primer layer of 0.8 to
0.9 .mu.m on the surface of the lens.
(3-2) Preparation of Composition for Hard Coat Layer and Formation
of Hard Coat Layer
[0101] 100 parts by mass of Butyl cellosolve and 155 parts by mass
of gamma-glycidoxypropyltrimethoxysilane were mixed and stirred
sufficiently to be uniform. 43 parts by mass of 0.1N aqueous
hydrochloric acid was dropped in the mixture while being stirred.
After further being stirred at an ambient temperature for 4 hours,
the mixture was put and left in a refrigerator for a whole day.
[0102] Subsequently, 0.3 parts by mass of a silicone-based
surfactant "L-7001" (trade name, produced by Nippon Unicar Company
Limited) was added and stirred. Then, 700 parts by mass of a fine
composite particle sol "Optolake 1120Z S25-A8" (trade name,
produced by CATALYSTS & CHEMICALS INC. CO., LTD, solid
concentration of 200% by weight), which mainly contains methanol
dispersible titanium dioxide, zirconium dioxide, and silicon
dioxide, was added and sufficiently stirred.
[0103] Further, Fe(III) acetylacetonato of 0.2 parts by mass was
added and stirred for 3 hours at an ambient temperature, which was
left in a refrigerator for a whole day so as to prepare a
composition for a hard coat layer.
[0104] Then, the lens base material L1 having the primer layer
obtained as described in (3-1) was coated with the composition for
the hard coat layer by dipping (pull speed 18 cm/min). The coated
lens base material was dried at 80 degrees C. for 20 minutes and
burned at 125 degrees C. for 120 minutes to form the hard coat
layer having a thickness of 2.0 to 2.2 .mu.m and a refractive rate
of 1.67 on the surface of the primary layer.
[0105] As described above, the lens base material L1 was subjected
to a surface finishing to have a double-layered structure of the
primer layer and the hard coat layer to prepare the lens base
material L3 with the hard coat layer.
4. Preparation of Lens Base Material L4 with Hard Coat Layer
[0106] Using the lens base material L2, the composition for the
hard coat layer was prepared in the same manner as in (3-2), then
coated and cured under the same condition as (3-2).
[0107] The hard coat layer formed on the lens base material L2 had
a thickness of 1.8 to 2.1 .mu.m and a refractive rate of 1.67. As
described above, the hard coat layer was provided on the lens base
material L2 as a single layer to prepare the lens base material L4
with the hard coat layer.
5. Preparation of Dyebath
(5-1) Dyebath A
[0108] A commercially available oil bath with a magnetic stirrer,
which was filled up with a silicone oil "KF968-1-100" (trade name,
produced by Shin-Etsu Chemical Co., Ltd.), was prepared. Then, a
beaker of 1 liter was put in the oil bath. 1 liter of the silicone
oil "KF968-1-100" (trade name, produced by Shin-Etsu Chemical Co.,
Ltd.) and 4 g of "Daiaresin Blue J" (trade name, produced by
Mitsubishi Chemical Industries, Ltd.) as a solvent dye were put in
the beaker. The temperature of the oil bath was set to 100 degrees
C., the oil was sufficiently stirred with a stirring bar in the oil
bath while being heated. After a temperature of the oil bath was
stabilized, a dyebath A was prepared. For dyeing the lens, a preset
temperature of the oil bath was changed to another predetermined
temperature. After the temperature was stabilized, the lens was
dyed.
(5-2) Dyebath B
[0109] A dyebath B was prepared in the same manner as the dyebath
A. As a solvent dye, 2 g of "Daiaresin Blue J" (trade name,
produced by Mitsubishi Chemical Industries, Ltd.), 1 g of "Diarejin
Red S" (trade name, produced by Mitsubishi Chemical Industries,
Ltd.), and 1 g of "Diaresin Yellow F" (trade name, produced by
Mitsubishi Chemical Industries, Ltd.) were added. Subsequently, the
same process was conducted as the described-above process for
preparing the dyebath A so as to prepare a dyebath B.
(5-3) Dyebath C
[0110] The same oil bath and beaker were used as those used for the
dyebath A. Except that 1 liter of a soybean oil produced by KANTO
CHEMICAL CO., INC.) was put in the beaker, the same process was
conducted as the above-described process for preparing the dyebath
A so as to prepare a dyebath C.
(5-4) Dyebath D
[0111] A commercially available water bath with a magnetic stirrer,
which was filled up with water, was prepared. Further, the beaker
of 1 liter was put in the water bath. 1 liter of purified water was
put in the beaker. As a surfactant, 5 cc of "Neonole 20" (trade
name; produced by Yamakawa Chemical Industry Co., Ltd.) was added,
and then the same solvent dye as that of the dyebath A was added.
The temperature of the water bath was set to 95 degrees C. After
the temperature of the water bath was stabilized, the aqueous
solution in the beaker was stirred with a stirring bar so as to
prepare a dyebath D.
EXAMPLES 1 TO 10, COMPARATIVES 1 TO 7
[0112] Using a lens base material and a dyebath under a temperature
and time as shown in Table 1, the lens base material was immersed
in the dyebath for dyeing a lens.
Evaluation Method
[0113] In Examples 1 to 10 and Comparatives 1 to 7, transmission of
a dyed lens was measured with a BPI photometer. From values of
transmission of the dyed lens, dye-affinity was evaluated as
follows.
Evaluation by Transmission After Dyeing
[0114] AA: strongly dyed (50 or less with the BPI photometer)
[0115] BB: moderately dyed (51 to 70 with the BPI photometer)
[0116] CC: weakly dyed (71 to 80 with the BPI photometer)
[0117] DD: Not dyed or slightly dyed (81 or more with the BPI
photometer)
[0118] Incidentally, the criteria of the above evaluation were as
follows.
[0119] Unless the transmission measured by the photometer was 50 or
less after the lens was dyed for approximately 60 minutes, it took
too much time for actually dyeing the lens strongly, which caused
problems. When the transmission measured by the photometer was 51
to 70, the lens may be dyed strongly by being dyed for a long time
(over 4 or 5 hours). When the transmission was 71 or more, it was
hard to dye the lens strongly even if being dyed for a long
time.
[0120] The evaluation results are shown in Table 1.
TABLE-US-00001 TABLE 1 Condition Evaluation Dyeing Dyeing
Transmission Lens Dyebath Temperature Time Dye-Affinity After
Dyeing Example 1 L1 A 120.degree. C. 60 minutes AA 37 Example 2 L1
A 110.degree. C. 60 minutes AA 49 Example 3 L1 A 105.degree. C. 60
minutes BB 57 Example 4 L1 B 120.degree. C. 60 minutes AA 38
Example 5 L2 A 120.degree. C. 60 minutes AA 35 Example 6 L2 A
110.degree. C. 60 minutes AA 46 Example 7 L2 B 120.degree. C. 60
minutes AA 36 Example 8 L1 C 120.degree. C. 60 minutes AA 38
Example 9 L3 A 120.degree. C. 60 minutes AA 37 Example 10 L4 A
120.degree. C. 60 minutes BB 56 Comparative 1 L1 A 95.degree. C. 60
minutes CC 73 Comparative 2 L1 B 95.degree. C. 60 minutes CC 75
Comparative 3 L1 D 95.degree. C. 60 minutes DD 85 Comparative 4 L1
D 95.degree. C. 600 minutes DD 81 Comparative 5 L3 D 95.degree. C.
60 minutes DD 84 Comparative 6 L3 D 95.degree. C. 600 minutes DD 81
Comparative 7 L4 D 95.degree. C. 60 minutes DD 85
[0121] As seen from the results in Table 1, since the oil bath and
the solvent dye were used for the episulfide resin lens base
material in Examples 1 to 4 and 8, favorable dyeing results were
obtained. Also, as seen from the results in Examples 1 to 3, as the
dyeing temperature was higher, more favorable results were
obtained.
[0122] Further, since the oil bath and the solvent dye were used
for the thiourethane resin lens base material in Examples 5 to 7,
favorable dyeing results were obtained.
[0123] In Examples 9 and 10, the lens base material with the hard
coat layer was dyed, and favorable dyeing results were also
obtained.
[0124] On the other hand, since the dyeing temperature was lower
than 100 degrees C. in Comparatives 1 and 2, the dye-affinity was
inferior compared to Examples 1 and 4.
[0125] Since the dyeing agent based on hot water was used in
Comparatives 3 to 7, the dyeing speed was extremely low and the
lens was slightly dyed. Additionally, the solvent dye was not
evenly dispersed in the hot water and therefore the lens was not
uniformly dyed. Even when the dyeing time was 10 times longer as in
Comparatives 4 and 6, considerable improvements were not
observed.
[0126] The invention is applicable to an optical lens or a
spectacle lens.
* * * * *