Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Hydrophilic copolymer particular suitable for
contact lenses and other medical purposes and method for
preparing the same.
The present invention relates to a hydrophilic
copolymer particularly suitable for contact lenses and
medical applications, and to a method for preparing this
hydrophilic copolymer.
Strongly swelling elastomers are known, which are
particularly suitable for various medical purposes, for the
manufacture of contact lenses and for other applications.
These known elastomers, however, are insuitable for certain
applications because of their insufficient mechanical
properties. Therefore, weakly crosslinked copolymers of
strongly hydrophilic N-vinylpyrrolidone with hydrophobic
alkyl methacrylate were developed (see British Patent no.
1,514,810), which exhibit, in addition to high swelling,
more convenient mechanical properties. Howeever, these
particular copolymers contain an undesirable extractable
portion. Moreover, their hydrophobic comonomer, in
particular methyl methacrylate, is highly volatile. For
this reason, these copolymers cannot be used for monomer
casting in open molds, such as, for example, for the
production of foils and contact lenses by the method of
centrifugal casting. Even the crosslinked triethylene
glycol methacrylate, which is known from US Patent no.
3,220,960 and also highly swells, has not sufficient
mechanical properties and therefore cannot be used for some
applications such as, for example, the manufacture of
contact lenses for long-termed wearing. The endeavour is to
develop for use in manufacturing lenses, a hydrophilic
copolymer which would be highly swelling and would keep
suitable mechanical properties, such as tensile strength,
elongation and elasticity modulus.
The present invention proposes a hydrophylic copo-
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lymer particularly suitable for the manufacture of contact
lenses and for other medical purposes, which overcomes all
of the above mentioned problems.
The hydrophylic copolymer according to the
invention is prepared by copolymerization of 10 - 90 wt.%,
preferably 40 - 80 wt.~, of a monomer of the general formula
I
CH = C - COO - (CH2CH2O)n CH2 2 (I)
H3
where n is 1 or 2, with 90 - 10 wt.~ of 2-hydroxyethyl
methacrylate and with 0.01 to 2 wt.% of at least one
crosslinking agent having at least two olefinic double
bonds, such as, for example, multifunctional esters or
amides of acrylic or methacrylic acid, in the presence of at
least one radical initiator.
The copolymerization is preferably carried out in
the presence of a polar solvent, advantageously in the
presence of glycerol, glycols and their derivatives, water,
dimethyl-formamide, dimethylsulfoxide, dimethylacetamide,
diacetine, isopropanol, or their mixture, with the weight
ratio of the solvent to the monomer mixture ranging from
1 : 99 to 50 : 50.
The radical initiator can be selected from the
group consisting of azo compounds, peroxides,
peroxocarbonates, peroxosulfates, photoinitiators based on
benzoin ethers and their derivatives, and initiation redox
systems. Advantageously, use will be ~ade of peroxosulate
- disulfite, peroxosulfate - alkylamines, and benzoyl
peroxide - alkylamines, in a concentration 0.01 - 3 wt.%.
If the copolymerization is carried out in the
absence of polar solvent or a mixture of polar solvents a
bulk copolymer is obtained. Such a bulk copolymer is
particularly useful for applications which require
:~26~;~4~?2
mechanical working. But this copolymerization in bulk may
be used also for the direct production of some articles.
In the presence of one or more polar solvents, the
resulting copolymer contains a suitably chosen amount of
solvent and is suitable for casting, e.g. for the
centrifugal casting of contact lenses. The sol~ent, which
would interfere in the mechanical working mentioned
hereinabove, here positively affects the swelling pressures
occuring during swelling of the final product.
Copolymers of 2-hydroxyethyl methacrylate with
diethylene glycol monomethacrylate and of 2-hydroxyethyl
methacrylate with triethylene glycol monomethacrylate are
particularly preferred. These copolymers can be prepared in
the presence of diethylene glycol dimethacrylate or
trimethylene glycol dimethacrylate and ethylene glycol
dimethacrylate, or in the presence of only one crosslinking
component, which may be an arbitrary diester of methacrylic
or acrylic acid with the corresponding alkyl glycol if the
starting monomers are completely free of their corresponding
diesters originating from their synthesis. Alternatively,
the copolymerization can be carried out in the presence of
methylene-bis-acrylamide, ethylene-bis-methacrylamide,
hexamethylene-bis-methacrylamide, and the like, as
crosslinking agents, or in the presence of their
combinations, always in such a way that at least three
components are entering the polymerization, two of which are
monomers and the third one is a crosslinking agent, whereas
one of two monoesters is always 2-hydroxyethyl methacrylate
and the other monoester is either diethylene glycol
monomethacrylate or triethylene glycol monomethacrylate. If
2-hydroxyethyl methacrylate is prepared from oxirane and
methacrylic acid, it may contain up to 0.190 wt.~ of
methacrylic acid, which amount is sufficient for the further
processing to contact lenses.
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The resulting hydrophilic terpolymer or tetra-
polymer have such high mechanical properties that it can be
used for the preparation of contact lenses or for medical
purposes only at the above given ratio of said monoesters,
provided that the admissible concentration of diesters or
triesters of acrylic or methacrylic acid or of diamides of
acrylic or methacrylic acid is maintained. At an increas-
ing ratio of diethylene glycol monomethacrylate (DEGMA) or
triethylene glycol monomethacrylate (TEGMA) to 2-hydroxy-
ethyl methacrylate (H~MA) and a constant content ofdiesters or their mixture, the content of water in the final
threedimensional hydrogel continuously increases and, for
this ratio of components according to the invention, hydro-
gels with suitable mechanical properties and an equilibrium
water content 55 - 76% are obtained.
It is also possible and suitable for the produc-
tion of high-swelling contact lenses, to extract with water
the solvent or any water-soluble low-molecular-weight por-
tion present in the crosslinked copolymer prepared in the
presence of the above mentioned polar solvent, and then to
dry it to a constant weight. The formed xerogel is excel-
lent for mechanical working. The drying is advantageously
carried out in saturated steam at a temperature above the
glass-transition temperature Tg of the prepared copolymer.
The advantage of this procedure, in comparison
with the method of preparation o~ contact lenses from
various types o~ xerogels used until now, is not only that
it makes it possible the perfect washing-ofE of low-
molecular-weight comoponents as was mentioned above, but
also that more ordered structure is obtained, with respect
to the inner stress of cross links during polymerization.
This ordered structure is maintained during drying and the
network resulting after the repeated swelling of a contact
lens made from the xerogel prepared in this way is without
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internal stress as a consequence of the ordered structure of
cross links, which is visualized in a polarized light. This
method of preparation also provides a high conversion of
polymerizing components, as compared to the preparation of
5 xerogel materials by polymerization without solvent.
Another advantage of this method is that it in-
creases the glass-transition temperature Tg six degrees
centrigrade per each percent part of washed-out monomeric
and low-molecular-weight portion, which favourably affects
10 the turning and polishing to the final shape of the contact
lens.
The advantage oE drying water-swollen precast
elements for turned contact lenses in saturated steam is
that such a drying removes the polymerization solvent, i.e.
15 water, from the three-dimensional structure under the con- Z
dition of perfect mobility of polymer chains and their side
segments (i.e. above the Tg of copolymer~, thus achieving
rapid withdrawal of solvent without damage to the tree-
dimensional structure while retaining the ratio of outer
20 dimensions and angles of the dried precast element with
respect to the swollen one at the given initial composition
of polymerization mixture.
The copolymers according to the invention have
surprisingly higher values of strength than the homopoly-
25 mers prepared from the above mentioned monomers DEGMA and
TEGMA, at a low elasticity modulus. In contrast to all
known higher-hydrophilic polymers used for the manufacturing
of contact lenses, especially from vinylpyrrolidone, the co-
polymers according to the invention are practically without
30 water soluble extracts. The copolymers according to the
invention do not contain in their structure hydrophilic
zones nor ionogenic groups and therefore substantially lower
deposits of eye proteins may be expected in comparison to
the known copolymers. The copolymers according to the
. .
~2~ 4~2
invention also achieve a sufficiently high equilibrium
content of water in the final product, so that they may be
used for the production of contact lenses for permanent
(long-term) wearing.
The invention is further illustrated in the
following, non-limitative examples.
Example 1
A mixture of 70 wt.% of 2-hydroxyethyl metha-
crylate (further HEMA) with 30 wt.~ of diethylene glycol
monomethacrylate (further DEGMA) containing 0.45 wt.% of
ethylene glycol dimethacrylate and 0.2 wt.% dicthylene
glycol dimethacrylate as a crosslinking agent, was mixed in
the amount of 60 wt.% with 40 wt.% of glycerol. This
mixture was polymerized with 0.5 wt.% of benzoin ethyl ether
related to the total mass of monomers for 15 minutes by
action of UV radiation. The resulting material contained
after swelling 49.6 wt.% of water, had a modulus of elas-
ticity in shear G = 1.03 kg.cm 2 and c~efficients of linear
expansion Kv = 1.09 for swelling i H2O and Kf = 1.08 for
swelling in physiologic saline. The coefficient of linear
expansion is defined as a ratio of the diametter of a test
piece in the swollen state to its dlameter after polymeri-
zation.
Example 2
A mixture of 60 wt.% HEMA and 40 wt.% DEGMA con-
30 taining 0.45 wt.% of ethylene glycol dimethacrylate and 0.2
wt.~ of diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.~ of benzoin ethyl ether related
to the total mass of monomers for 15 minutes by action of UV
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radiation. The resulting material contained, after
swelling, 53.6 wt.% of water and had a modulus of elasticity
in shear G = 0.85 kg.cm 2 and coefficients of linear expan-
sion Kv = 1.12 and Kf = 1.12.
Example 3
A mixture of 50 wt. HEMA and 50 wt.~ DEGMA con-
taining 0.45 wt.~ of ethylene glycol dimethacrylate and 0.2
wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total mass of monomers for 15 minutes under UV radia-
tion. The resulting material contained, after swelling,
59.5 wt.% of water, had an elongation of 120%, a strength
1.50 kg.cm , G = 0.73 kg.cm 2, Kv = 1.15, and Kf = 1.15.
Example 4
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.2 wt.% of diethylene glycol dimethacrylate and 0.7
wt.% of triethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total mass of monomers for 15 minutes under UV
radiation. The resulting material contained, after swel-
ling, 63.1 wt.% of water and had G = 0.63 kg.cm , Kv = 1.21
and Kf = 1.20.
_xample 5
A mixture of 30 wt.% HEMA and 70 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
0.15 wt.% of ethylene glycol dimethacrylate, was mixed in
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the amount of 60 wt.% with 40 wt.% of glycerol. This
mixture was polymerized with 0.5 wt.% of benzoin ethyl ether
related to the total mass of monomers for 25 minutes under
UV radiation. The resulting material contained after swel-
ling 68 wt.% of water at G = 0.57 kg.cm 2, Kv = 1.2~ and
Kf = 1.23.
Example 6
A mixture of 70 wt.% HEMA and 30 wt.% DEGMA con-
taining 0.3 wt.% of ethylene glycol dimethacrylate, 0.20
wt.% of diethylene glycol dimethacrylate and 0.3 wt.~ of
triethylene glycol dimethacrylate was mixed in the amount of
70 wt.% with 30 wt.% of glycerol. This mixture was
polymerized with 0.5 wt.~ of benzoin ethyl ether related to
the total mass of monomers for 15 minutes under UV radia-
tion. The resulting material contained, after swelling, 50.1
wt.% of water at G = 1.19 kg.cm ~ Kv = 1.14 and Kf = 1.14.
Example 7
A mixture of 60 wt.% HEMA and 40 wt.~ DEGMA con-
taining 0.5 wt.% of ethylene glycol dimethacrylate was mixed
in the amount of 70 wt.~ with 30 wt.~ of glycexol. This
mixture was polymerized with 0.5 wt~ of benzoin ethyl ether
related to the total amount of monomers for 15 minutes under
UV radiation. The resulting material contained, after swel-
ling, 54.2 wt.% of water at G = 0.97 kg.cm 2, Kv = 1.17 and
Kf = 1.17.
Example 8
,~ .
A mixture o~ 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.6 wt.~ of diethylene glycol dimethacrylate and
:~;Z6~ 2
0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 70 wt.% with 30 wt.% of glycerol. This mixture
was polymerized with O.S wt.% of benzoin ethyl ether for 15
minutes under UV xadiation. The resulting material
contained, after swelling, 63.1 wt.% of water at G = 0.75
kg.cm , Kv = 1.25 and Kf = 1.25.
Example 9
A mixture of 30 wt.% HEMA and 70 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 70 wt.% with 30 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether for 15
minutes under UV radiation. The resulting material
contained, after swelling, 67.4 wt.% of water at G = 0.67
kg.cm2, Kv = 1.29, Kf = 1.28.
Example 10
A mixture of 70 wt.% HEMA and 30 wt.% DEGMA con-
taining 0.45 wt.% of ethylene glycol dimethacrylate and 0.2
wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 80 wt.96 with 20 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether for 15
minutes under UV radiation. The resulting material contain-
ed, after swelling, 49.6 wt.% of water at G = 1.39 kg.cm 2;
elongation 110%, strength 2.2 kg.cm ~ Kv ~ 1.18 and Kf =
1.17.
Example 11
A mixture of 60 wt.% HEMA and 40 wt.% DEGMA con-
taining 0.45 wt.% of ethylene glycol dimethacrylate and 0.2
_ g _
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wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 80 wt.% with 20 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after swel-
ling, 53.6 wt.% of water at G = 1.22 kg.cm ; Kv = 1.22,
Kf = 1.21.
Example 12
A mixture of 50 wt.~ HEMA and 50 wt.% DEGMA con-
taining 0.45 wt.% of ethylene glycol dimethacrylate and 0.2
wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 80 wt.~ with 20 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.~ of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after
swelling, 58.9 wt,% of water at G = 1.08 kg.cm ; Kv =
1.23, Kf = 1.21.
Example 13
A mixture of 40 wt.~ ~EMA and 60 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
0.15 wt.~ of ethylene glycol dimethacrylate was mixed in the
amount of 80 wt.~ with 20 wt.~ of glycerol. This mixture
was polymerized with 0.5 wt.~ of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after swel-
30 ling, 60.1 wt.~ of water at G = 0.94 kg.cm ; Kv = 1-27,
Kf = 1.26.
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Example _
A mixture of 30 wt.% HEMA and 70 wt.% DEGMA con-
taining 0.5 wt.% of ethylene glycol dimethacrylate was mixed
in the amount of 80 wt.% with 20 wt.% of glycerol. This
mixture was polymerized with 0.5 wt.~ of benzoin ethyl ether
related to the total arnount of monomers for 15 minutes under
UV radiation. The resulting material contained, after swel-
ling, 63.7 wt.% of water at G = 0.82 kg.cm ; Kv = 1.31,
Kf = 1.30.
Example 15
A mixture of 60 wt.% HEMA and 40 wt.% DEGMA con-
taining 0.45 wt.% of ethylene glycol dimethacrylate and 0.2
wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 90 wt.% with 10 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after swelling,50.7 wt.% of water at G = 1.43 kg.cm ; Kv = 1.23, Kf =
1.21.
Example 16
A mixture of 50 wt.% HEMA and 50 wt.% DEGMA con-
taining 0.5 wt.% of ethylene glycol dimethacrylate was mixed
in the amount of 90 wt.% with 10 wt.% of glycerol. This
mixture was polymerized with 0.5 wt.~ of benzoin ethyl ether
related to the total amount of monomers for 15 minutes under
UV radiation. The resulting material contained, after swel-
ling, 53.6 wt.% of water at G = 1.21 kg.cm ; strength 1.80
kg.cm , elongation 80%; Kv = 1.26 and Kf = 1.24.
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Example 17
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
5 0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 90 wr.% with 10 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after swel-
10ling, 58.3 wt.% of water at G = 1.08 kg.cm ; KV = 1.31 and
Kf = 1.28.
Example 18
15A mixture of 30 wt.~ HEMA and 70 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 90 wt.% with 10 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after swel-
ling, 63.1 wt.% of water at G = 0.94 kg.cm 2; Kv = 1.37 and
Kf = 1.33.
Example 19
A mixture oE 60 wt.~ ~EMA and 40 wt.% DEGMA con-
taining 0.~ wt.% of diethylene glycol dimethacrylate and
0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.~ of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after swel-
ling, 50 wt.% of water at G = 0.85 kg.cm 2, strength 2.15
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kg.cm 2, strength 2.15 kg.cm 2, elongation 220%, Kv = Kf =
1.10.
Example 20
A mixture of 60 wt.% HEMA and 40 wt.% DE&MA con-
taining 0.20 wt.% of ethylene glycol dimethacrylate and 0.15
wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of ~enzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contains, after swelling,
54 wt.% of water at G = 0.75 kg.cm 2, strength 2.10 kg.cm 2
and elongation 230%; Kv = Kf = 1.14.
Example 21
A mixture of 60 wt.% HEMA and 40 wt.% DEGMA con-
taining 0.6 wt.% of ethylene glycol dimethacrylate and 0.6
wt.% diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after
swelling, 49 wt.% of water at G = 1.1 kg.cm , elongation
150% and stren~th 2.40 kg.cm 2.
Example 22
A mixture of 50 wt.% HEMA and 50 wt.% DEGMA con-
taining 0.15 wt.% of ethylene glycol dimethacrylate was
mixed in the amount of 85 wt.% with 15 wt.% of glycerol.
This mixture was polymerized with 0.5 wt.% of benzoin ethyl
ether related to the total amount of monomers for 15 minutes
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:~;26, g~92
under W radiation. The resulting material contained, after
swelling, 55 wt.% of water at G - 1.10 kg.cm 2, strength
2.60 kg.cm 2 and elongation 160%.
Example 23
A mixture of 40 wt.% HEMA and 60 wt.~ DEGMA
containing 0.20 wt.% of ethylene glycol dimethacrylate and
0.15 wt.~ of cliethylene glycol dimethacrylate was mixed in
the amount of 85 wt.% with 15 wt.% of glycerol. The mixture
was polymerized with 0.5 wt.~ of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contains, after swelling,
62 wt.~ of water at G = 0.70 kg.cm 2, strength 1.6 kg.cm 2
and elongation 135%.
Exanple 24
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and0.15 wt.% ethylene glycol dimethacrylate was mixed in the
amount of 85 wt.% with 15 wt.% of glycerol. This mixture
was pol~merized with 0.5 wt.~ of benzoin ethyl ether related
to the total amount of monomerr for 15 minutes by UV
radiation. The resulting material contained, after
swelling, 62 wt.% of water at G = 0.74 kg.cm ~, strength
1.85 kg.cm and elongation 150%.
Example 25
A mixture of 30 wt.% HEMA and 70 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 85 wt.% with 15 wt.% of glycerol. This mixture
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~26~74~2
was polymerized with 0.5 wt.% of benzoin ethyl ether
related to the total amount of monomers for 15 minutes by UV
radiation. The resulting material contained, after swel-
ling, 64 wt.~ of water at G = 0.82 kg.cm 2, strength 2.60
kg.cm and elongation 205%.
Example 26
A mixture of 60 wt.% HEMA and 40 wt.% DEGMA con-
taining 0.20 wt.% of ethylene glycol dimethacrylate and 0.15
wt.% of diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.1 wt.% of diisopropyl peroxocarbonate
related to the total amount of monomers for 16 hours at
60C. The resulting material contained, after swelling, 55
wt.% of water at G = 0.70 kg.cm 2,
Example 27
A mixture of 60 wt.~ HEMA and 40 wt.% DEGMA con-
taining 0.20 wt.% of ethylene glycol dimethacrylate and 0.15
wt.% diethylene glycol dimethacrylate was mixed in the
amount of 80 wt.% with 20 wt.% of glycerol. This mixture
was polymerized with 0.1 wt.~ of diisopropyl peroxocarbonate
related to the total amount of monomers for 16 hours at
60C. The resulting material contained, after swelling, 54
wt.% of water at G = 1.01 kg.cm 2,
Example 28
A mixture of 50 wt.% HEMA and 50 wt.% DEGMA con-
taining 0.15 wt.% of ethylene glycol dimethacrylate was
mixed in the amount of 60 wt.% with 40 wt.% of glycerol.
This mixture was polymerized with 0.1 wt.% of diisopropyl
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peroxocarbonate related to the total amount of monomers at
60C for 16 hours. The resulting material contained, after
swelling, 58.9 wt.% of water at G = 0.62 kg.cm 2.
Example 29
A mixture of 50 wt.% HEMA and 50 wt.% DEGMA con-
taining 0.15 wt.% of ethylene glycol dimethacrylate was
mixed in the amount of 80 wt.% with 20 wt.% of glycerol.
This mixture was polymerized with 0.1 wt.% diisopropyl
peroxocarbonate related to the total amount of monomers for
16 hours at 60C. The resulting material contained, after
swelling, 58.9 wt.% of water at G = 1.05 kg.cm
Example 30
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.20 wt.% of ethylene glycol dimethacrylate and 0.15
wt.~ of diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.% of glycerol. This mixture
was polymerized with 0.1 wt.% of diisopropyl peroxocarbonate
related to the total amount of monomers at 60C for 16
hours. The resulting material contained, after swelling,
65.7 wt.% of water at G = 0.50 kg.cm 2.
Example 31
A mixture of 40 wt.% HEMA and 60 wt.~ DEGMA con-
taining 0.20 wt.% of ethylene glycol dimethacrylate and
0.15 wt.% of diethylene glycol dimethacrylate was mixed in
the amount of 80 wt.% with 20 wt.% of glyceral. This
mixture was polymerized with 0.1 wt.% of diisopropyl
peroxocarbonate related to the total amount of monomers for
16 hours at 60C. The resulting material contained, after
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swelling, 64.3 wt.% of water at G = 0.75 kg.cm 2.
Example 32
A mixture of 60 wt.~ HEMA and 40 wt.~ DEGMA con-
taining 0.15 wt.~ of ethylene glycol dimethacrylate was
mixed in the amount of 60 wt.% with 40 wt.% of glycerol.
This mixture was polymerized with 0.20 wt.% of a~obisiso-
butyronitrile related to the total amount of monomers for 16
hours at 60C. The resulting material contained, after
swelling, 54.7 wt.% of water at G = 0.75 kg.cm
Example 33
A mixture of 60 wt.% HEMA and 40 wt.% DEGMA con-
taining 0.20 wt.% of ethylene glycol dimethacrylate and O.lS
wt.% diethylene glycol dimethacrylate was mixed in the
amount of 60 wt.% with 40 wt.~ of glycerol. This mixture
was polymerized with 0.2 wt.% ammonium peroxosulfate for
hour at 78C. The resulting material contained, after swel-
ling, 54.9 wt.~ of water at G = 0.75 kg.cm 2.
Example 34
A mixture of 60 wt.~ HEMA and 40 wt.% DEGMA
containing 0.20 wt.% of ethylene glycol dimethacrylate and
0.15 wt.% of diethylene glycol dimethacrylate was mixed in
the amount of 60 wt.% with 40 wt.~ of glycerol. This
mixture was polymerized with 0.5 wt.% of benzoin ethyl ether
for lS minutes by W irradiation. The resulting material
contained, after swelling, 55 wt.% of water at G = 0.70
kg.cm 2.
,: , , ' . :
~6~;J4~Z
Example 35
A mixture of 20 wt.% HEMA and 80 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
S 0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 85 wt.~ glycerol. This mixture was polymerized
with 0.5 wt.% of benzoin ethyl ether for 15 minutes by Uv
radiation. The resulting material contained, after
swelling, 70 wt~% of water at G = 0.38 kg.cm , elongation
160% and strength 1.03 kg.cm 2.
Example 36
A mixture of 10 wt.% HEMA and 90 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and
0.15 wt.% of ethylene glycol dimethacrylate was mixed in the
amount of 85 wt.~ with 15 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% benzoin ethyl ether for 15
minutes by W radiation. The resulting material contained,
after swelling, 74 wt.% of water at G = 0.4 kg.cm 2, elonga-
tion 160% and strength 1.00 k~.cm 2.
Example 37
A mixture of 60 wt.~ of 2-hydroxyethyl
methacrylate (further HEMA) and 40 wt.~ of diethylene glycol
monomethacrylate (further DEGMA) containing 0.20 wt.% of
ethylene glycol dimethacrylate and 0.15 wt.~ of diethylene
glycol dimethacrylate was polymerized with 0.1 wt.% of
diisopropyl peroxocarbonate related to the total amount of
monomers for 16 hours at 60C. The resulting material
contained, after swelling, 52.2 wt.~ of water at an
elasticity modulus in shear G = 3.25 kg.cm 2 and was
suitable for turned contact lenses.
- 18 -
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Example 38
A mixture oE 50 wt.~ HEMA and 50 wt.% DEGMA con-
taining 0.15 wt.% ethylene glycol dimethacrylate was poly-
merized with 0.1 wt.% of diisopropyl peroxocarbonate related
to the total a~ount of monomers for 16 hours at 60C. The
resulting material contained, after swelling, 52.2% of water
at G = 2.90 kg.cm 2 and was suitable for turned contact
lenses.
Example 39
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.20 wt.~ of ethylene glycol dimethacrylate and 0.15
wt.% diethylene glycol dimethacrylate was polymerized with
0.1 wt.~ of diisopropyl peroxocarbonate related to the total
amount of monomers for 16 hours at 60C. The resulting
material contained, after swelling, 56.2 wt.% of water at
G = 2.70 kg.cm 2.
Example 40
A mixture of 30 wt.~ HEMA and 70 wt.% DEGMA con-
taining 0.6 wt.% of diethylene glycol dimethacrylate and0.15 wt.% ethylene glycol dimethacrylate was polymerized
with 0.1 wt.% of diisopropyl peroxocarbonate related to the
total amount of monomers for 16 hours at 60 C. The
resulting material contained, after swelling, 60 wt.% of
water at G = 2.32 kg.cm 2.
Example 41
A mixture o 20 wt.% HEMA and 80 wt.% DEGMA con-
- 19 -
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taining 0.20 wt.% of ethylene glycol dimethacrylate and 0.15
wt.% of diethylene glycol dimethacrylate was polymerized
with 0.1 wt.% of diisopropyl peroxocarbonate related to the
total amount of monomers for 16 hours at 60C. The
resulting material contained, after swelling, 63.7 wt.% of
water at G = 1.~3 kg.cm
Example 42
A mixture of 10 wt.% HEMA and 90 wt.% DEGMA con-
taining 0.15 wt.% of ethylene glycol dimethacrylate was
polymerized with 0.1 wt.% of diisopropyl peroxocarbonate
related to the total amount of monomers for 16 hours at
60 C. The resulting material contained, after swelling,
15 66.6 wt.% of water at G = 1.13 kg.cm 2.
Example 43
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.5 wt.% of ethylene glycol dimethacrylate waspolymerized with 0.2 wt.% of azobisisobutyronitrile related
to the total amount of monomers for 16 hours at 60C. The
resulting material contained, after swelling, 54.7 wt.~ of
water at G = 2.90 kg.cm 2.
Example 44
A mixture of 40 wt.% HEMA and 60 wt.~ DEGMA con-
taining 0.6 wt.% of ethylene glycol dimethacrylate was
polymerized with 0.2 wt.% of azobisisobutyronitrile related
to the total amount of monomers for 16 hours at 60C. The
resulting material contained, after swelling, 53 wt.% of
water at G = 3.05 kg.cm
- 20 -
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Example 45
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con~
taining 0.20 wt.% of ethylene glycol dimethacrylate and
0.15 wt.% of diethylene glycol dimethacrylate was
polymerized with 0.1 wt.% of diisopropyl peroxocarbonate
related to the total amount of monomers for 16 hours at
60 C. The resulting material contained, after swelling,
56.2 wt.% of water at G = 2.70 cm 2,
Example 46
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
taining 0.3 wt.% of ethylene glycol dimethacrylate, 0.20
wt.% of diethylene glycol dimethacrylate and 0.3 wt.% of
triethylene glycol dimethacrylate was polymerized with 0.2
wt.% ofammonium peroxosulfate related to the total amount of
monomers for 1 hour at 78C. The resulting material
contained, after swelling, 56 wt.% of water at G = 2.72
kg.cm
Example 47
A mixture of 40 wt.% HEMA and 60 wt.% DEGMA con-
25 taining 0.20 wt.% of ethylene glycol dimethacrylate and 0.15
wt.% of diethylene glycol dimethacrylate was polymerized
with 0.5 wt.% of benzoin ethyl ether for 15 minutes by UV
radiation. The resulting material conttained, after
swelling, 56.3 wt.% of water at G = 2.i2 kg.cm 2.
Example 48
A mixture of 40 wt.% ~EMA and 60 wt.% DEGMA
containing 0.20 wt.% of ethylene glycol dimethacrylate and
- 21 -
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O.lS wt.% of diethylene glycol dimethacrylate was
polymerized with 0.5 wt.% of benzoin ethyl ether for 15
minutes by UV radiation. The resulting material contained,
after swelling, 56.2 wt.% of water at G = 2.70 kg.cm 2.
Example 49
A mixture of 90 wt.% of 2-hydroxyethyl
methacrylate (HEMA) and 10 wt.% of triethylene glycol
10 methacrylate (further TEGMA) containiny 0.4 wt.% of ethylene
glycol dimethacrylate and 0.20 wt.~ of triethylene glycol
dimethacrylate as a crosslinking agent was polymerized with
0.5 wt.% of benzoin ethyl ether related to the total amount
of monomers for 15 minutes by W radiation. The resulting
15 material contains, after swelling, 48 wt.% of water.
Example 50
A mixture of 80 wt.% HEMA and 20 wt.% TEGMA con-
20 taining 0.4 wt.% of ethylene glycol dimethacrylate and 0.20
wt.% triethylene glycol dimethacrylate was mixed in the
amount of 80 wt.% with 20 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomer5 for 15 minutes by W radiation.
25 The resulting material contained, after swelling, 53 wt.% of
water at an elasticity modulus in shear G = 1.33 kg.cm 2,
Example 51
A mixture of 50 wt.% HEMA and 50 wt.~ TEGMA con-
taining 0.3 wt.% of ethylene glycol dimethacrylate and 0.6
wt.% triethylene glycol dimethacrylate was mixed in the
amount of 80 wt.% with 20 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
- 22 -
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to the total amount of monomers for lS minutes by UV
radiation. The resulting material contained, after
swelling, 67 wt.% of water at an elasticity modulus in shear
G = 0.50 kg.cm
Example 52
A mixture of 15 wt.% HEMA and 85 wt.~ TEGMA con-
taining 0.3 wt.% of ethylene ~lycol dimethacrylate and 0.6
wt.% of triethylene glycol methacrylate was mixed in the
amount of 80 wt.% with 20 wt.% of glycerol. This mixture
was polymerized with 0.5 wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes under UV
radiation. The resulting material contained, after
swelling, 77 wt.~ of water.
Example 53
A mixture of 40 wt.% HEMA and 60 wt.% TEGMA con-
taining 0.3 wt.~ of ethylene glycol dimethacrylate and 0.6wt.% of triethylene glycol dimethacrylate was mixed in the
amount of 70 wt.% with 30 wt.% of glycerol. This mixture
was polymerized with O.S wt.% of benzoin ethyl ether related
to the total amount of monomers for 15 minutes by UV
radiation. The resulting material contained 76 wt.% of
water after swelling at G = 0.45 kg.cm 2.
Example 54
A mixture of 50 wt.% HEMA and 50 wt.% TEGMA con-
taining 0.5 wt.% of ethylene glycol dimethacrylate was mixed
in the amount of 60 wt.~ with 40 wt.% of glycerol.
This mixture was polymerized with 0.5 wt.~ of benzoin ethyl
ether related to the total amount of monomers for 15 minutes
- 23 -
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under UV radiation. The resulting material contained, after
swelling, 69 wt.~ of water.
Example 55
A mixture of 30 wt.% HEMA and 70 wt.% DEGMA containing
0.3 wt.% of ethylene-bis-acrylamide and 0.2 wt.% diethylene
glycol dimethacrylate was mixed in the amount 60 wt.% with
40 wt.% of glycerol. This mixture was polymerized with 0.5
wt.% benzoin ethyl ether related to the total amount of
monomers for 15 minutes by UV radiation. The resulting
material contained, after swelling, 67.5 wt.% of water at G
= 0.56 kg.cm ~ Kv = 1.24 and Kf = 1.225.
Example 56
A mixture of 60 wt.% DEGMA and 40 wt.% HEMA con-
taining 0.4 wt.% of hexamethylene-bis-acrylamide and 0.35
wt.% of methylene-bis-acrylamide was mixed in the amount of
wt.% with 25 wt.% of glycerol. This mixture was
polymerized with 0.1 wt.% of diisopropyl peroxocarbonate
related to the whole mixture at 60C ~or 15 minutes. The
resulting material contained, after swelling, 63 wt.% of
water at G = 0.75 kg.cm 2, Kv = 1.25 and Kf = 1.25.
- 24 -
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