U.S. patent application number 10/676173 was filed with the patent office on 2005-04-21 for polymerizable materials.
Invention is credited to Chapoy, Lawrence L., Phelan, John Christopher, Quinn, Michael Hugh.
Application Number | 20050085585 10/676173 |
Document ID | / |
Family ID | 34526073 |
Filed Date | 2005-04-21 |
United States Patent
Application |
20050085585 |
Kind Code |
A1 |
Quinn, Michael Hugh ; et
al. |
April 21, 2005 |
Polymerizable materials
Abstract
The present invention provides a polymerizable material for
making a polymeric article, the polymerizable material comprising:
a water-soluble polyvinyl alcohol having crosslinkable groups; and
a modifier in an amount sufficient to improve one or more physical
properties of a polymeric article made from the polymerizable
material, wherein the one or more physical properties are selected
from the group consisting of stress at break (N/mm.sup.2),
percentage of elongation at break, toughness or energy to break
(N.multidot.mm), and susceptibility to fracture. The modifier is
selected from the group consisting of nanoparticles having a
hydrophilic surface, a copolymer having hydrophobic groups or units
for imparting at least one desired physical property to said
ophthalmic device and hydrophilic groups or units in an amount
sufficient to render the copolymer miscible with the polyvinyl
alcohol, and mixtures thereof. In addition, the present invention
provides a polymeric article obtained by polymerization of a
polymerizable material of the invention and also a method for
modifying one or more physical properties of a hydrogel article
obtained from the polymerization of a crosslinkable polymer.
Inventors: |
Quinn, Michael Hugh;
(Valparaiso, IN) ; Chapoy, Lawrence L.;
(Barrington Hills, IL) ; Phelan, John Christopher;
(Gurnee, IL) |
Correspondence
Address: |
NOVARTIS
CORPORATE INTELLECTUAL PROPERTY
ONE HEALTH PLAZA 104/3
EAST HANOVER
NJ
07936-1080
US
|
Family ID: |
34526073 |
Appl. No.: |
10/676173 |
Filed: |
October 1, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60420626 |
Oct 23, 2002 |
|
|
|
Current U.S.
Class: |
524/557 |
Current CPC
Class: |
G02B 1/043 20130101;
C08L 33/26 20130101; C08L 29/04 20130101; C08L 75/04 20130101; C08L
29/04 20130101; C08L 39/06 20130101; C08L 29/04 20130101; C08L
2666/04 20130101; C08L 2666/20 20130101; C08L 29/04 20130101; G02B
1/043 20130101 |
Class at
Publication: |
524/557 |
International
Class: |
C08J 003/00 |
Claims
What is claimed is:
1. A polymerizable material for making an ophthalmic device,
comprising: a water-soluble polyvinyl alcohol having crosslinkable
groups; and a modifier in an amount sufficient to improve one or
more physical properties of the ophthalmic device made from the
polymerizable material, wherein the one or more physical properties
are selected from the group consisting of stress at break
(N/mm.sup.2), percentage of elongation at break, toughness or
energy to break (N.multidot.mm), and susceptibility to
fracture.
2. A polymerizable material of claim 1, wherein said modifier is
selected from the group consisting of nanoparticles having a
hydrophilic surface, a copolymer having hydrophobic groups or units
for imparting at least one desired physical property to said
ophthalmic device and hydrophilic groups or units in an amount
sufficient to render the copolymer miscible with the polyvinyl
alcohol, and mixtures thereof.
3. A polymerizable material of claim 2, wherein said water-soluble
polyvinyl alcohol is a polyhydroxyl compound which has a weight
average molecular weight of at least about 2000 and which comprises
from about 0.5 to about 80%, based on the number of hydroxyl groups
in the poly(vinyl alcohol), of units of the formula I, I and II, I
and III, or I and II and III 6in which R is alkylene having up to
12 carbon atoms, R.sub.1 is hydrogen or lower alkyl, R.sub.2 is an
olefinically unsaturated, electron-withdrawing, crosslinkable
radical having up to 25 carbon atoms, and R.sub.3 is hydrogen, a
C.sub.1-C.sub.6 alkyl group or a cycloalkyl group, 7wherein R and
R.sub.3 are as defined above, and R.sub.7 is a primary, secondary
or tertiary amino group or a quaternary amino group of the formula
N.sup.+(R').sub.3X.sup.-, in which each R', independently of the
others, is hydrogen or a C.sub.1-C.sub.4 alkyl radical and X is
HSO.sub.4.sup.-, F.sup.-, Cl.sup.-, Br.sup.-, I.sup.-,
CH.sub.3COO.sup.-, OH.sup.-, BF.sup.-, or H.sub.2PO.sub.4.sup.-,
8in which R and R.sub.3 are as defined above, and R.sub.8 is the
radical of a monobasic, dibasic or tribasic, saturated or
unsaturated, aliphatic or aromatic organic acid or sulfonic
acid.
4. A polymerizable material of claim 3, wherein said water-soluble
polyvinyl alcohol is a polyhydroxyl compound which has a molecular
weight of at least about 2000 and which comprises from about 0.5 to
about 80%, based on the number of hydroxyl groups in the poly(vinyl
alcohol), of units of the formula I, wherein R.sub.2 is a radical
of formula IV or formula V
--CO--NH--(R--NH--CO--O).sub.q--R.sub.6--O--CO--R.sub.4 (IV)
--[CO--N H--(R--NH--CO--O).sub.q--R.sub.6--O].sub.p--CO--R.sub.4
(V) in which p and q, independently of one another, are zero or
one, and R.sub.5 and R.sub.6, independently of one another, are
lower alkylene having 2 to 8 carbon atoms, arylene having 6 to 12
carbon atoms, a saturated bivalent cycloaliphatic group having 6 to
10 carbon atoms, arylenealkylene or alkylenearylene having 7 to 14
carbon atoms or arylenealkylenearylene having 13 to 16 carbon
atoms, and in which R.sub.4 is an olefinically unsaturated
copolymerizable radical having 2 to 24 carbone atoms, preferably
having 2 to 8 carbonatoms, more preferably having 2 to 4 carbon
atoms.
5. A polymerizable material of claim 3, wherein said modifier is
composed of the nanopaticles having a hydrophilic surface.
6. A polymerizable material of claim 5, wherein the nanoparticles
are nano-sized silica fillers.
7. A polymerizable material of claim 3, wherein said modifier is
composed of one or more copolymers each having hydrophobic groups
or units for imparting at least one desired physical property to
said ophthalmic device and hydrophilic groups or units in an amount
sufficient to render the copolymer miscible with the crosslinkable
polyvinyl alcohol.
8. A polymerizable material of claim 7, wherein said modifier is a
N-vinyl lactam copolymer which is a copolymerization product of at
least one N-vinyl lactam with one or more hydrophobic monomer,
wherein said at least one N-vinyl lactam has a structure of formula
(VI) 9in which R.sub.1 g is an alkylene di-radical having from 2 to
8 carbon atoms, R.sub.20 is hydrogen, C.sub.1-C.sub.7 alkyl, aryl
having up to 10 carbon atoms, aralkyl or alkaryl having up to 14
carbon atoms, and R.sub.21 is hydrogen or lower alkyl having up to
7 carbon atoms.
9. A polymerizable material of claim 8, wherein said N-vinyl lactam
is N-vinyl pyrrolidone.
10. A polymerizable material of claim 7, wherein said modifier is a
N,N-dialkylmethacrylamide copolymer which is a copolymerization
product of a N,N-di-C.sub.2-C.sub.4 alkyl methacrylamide with at
least one hydrophobic monomer.
11. A polymerizable material of claim 10, wherein the
N,N-di-C.sub.2-C.sub.4 alkyl methacrylamide is
N,N-dimethylmethacrylamide- .
12. A polymerizable material of claim 7, wherein said modifier is a
non-crosslinkable polyurethane having a molecular weight of at
least about 2000, or a crosslinkable polyurethane.
13. A polymerizable material of claim 12, wherein said
non-crosslinkable polyurethane is the reaction product of an
isocyanate-capped polyurethane with water and amine, wherein said
crosslinkable polyurethane is the reaction product of the
isocyanate-capped polyurethane with an ethylenically unsaturated
amine (primary or secondary amine) or an ethylenically unsaturated
monohydroxy compound, wherein said isocyanate-capped polyurethane
is a copolymerization product of (a) at least one polyalkylene
glycol of formula HO--(R.sub.9--O).sub.n--(R.sub.1-
0--O).sub.m--(R.sub.11--O).sub.l--H (1) wherein R.sub.9, R.sub.10,
and R.sub.11, independently of one other, are each linear or
branched C.sub.2-C.sub.4-alkylene, and n, m and l, independently of
one another, are each a number from 0 to 100, wherein the sum of
(n+m+l) is 5 to 100, (b) at least one branching agent selected from
the group consisting of (i) a linear or branched aliphatic
polyhydroxy compound of formula R.sub.12--(OH).sub.x (2), wherein
R.sub.12 is a linear or branched C.sub.3-C.sub.18 aliphatic
multi-valent radical and x is a number .gtoreq.3, (ii) a polyether
polyol, which is the polymerization product of a compound of
formula (2) and a glycol, (iii) a polyester polyol, which is the
polymerization product of a compound of formula (2), a dicarboxylic
acid or a derivative thereof and a diol, and (iv) a cycloaliphatic
polyol selected from the group consisting of a
C.sub.5-C.sub.8-cycloalkane which is substituted by .gtoreq.3
hydroxy groups and which is unsubstituted by alkyl radical, a
C.sub.5-C.sub.8-cycloalkane which is substituted by .gtoreq.3
hydroxy groups and which is substituted by one ore more
C.sub.1-C.sub.4 alkyl radicals, and an unsubstituted mono- and
disaccharide, (v) an aralkyl polyol having at least three hydroxy
C.sub.1-C.sub.4 alkyl radicals, and (c) at least one di- or
polyisocyanate of formula R.sub.13--(NCO).sub.y (3) wherein
R.sub.13 the multivalent radical of a linear or branched
C.sub.3-C.sub.24 aliphatic polyisocyanate, the multivalent radical
of a C.sub.3-C.sub.24 cycloaliphatic or aliphatic-cycloaliphatic
polyisocyanate, or the multivalent radical of a C.sub.3-C.sub.24
aromatic or araliphatic polyisocyanate, and y is a number from 2 to
6, wherein said ethylenically unsaturated monohydroxy compound is a
hydroxy-substituted lower alkylacrylate, a hydroxy-substituted
lower alkylmethacrylate, a hydroxy-substituted lower
alkyl-acrylamides, a hydroxy-substituted lower
alkyl-methacrylamide, or a hydroxy-substituted lower
alkylvinylether, wherein said ethylenically unsaturated amine has
formula (4), (4') or (4") 10In which, .cndot.l, j and k,
independent of one another, are o or 1; R.sub.14 is hydrogen, a
linear or branched C.sub.1-C.sub.24 alkyl, a C.sub.2-C.sub.24
alkoxyalkyl, a C.sub.2-C.sub.24 alkylcarbonyl, a C.sub.2-C.sub.24
alkoxycarbonyl, an unsubstituted or C.sub.1-C.sub.4 alkyl- or
C.sub.1-C.sub.4 alkoxy-substituted C.sub.6-C.sub.10 aryl, a
C.sub.7-C.sub.18 aralkyl, a C.sub.13-C.sub.22 arylalkylaryl, a
C.sub.3-C.sub.8 cycloalkyl, a C.sub.4-C.sub.14 cycloalkylalkyl, a
C.sub.7-C.sub.18 cycloalkylalkylcycloalkyl, a C.sub.5-C.sub.20
alkylcycloalkylalkyl, or an aliphatic-heterocyclic radical; Z is a
C.sub.1-C.sub.12 alkylene radical, phenylene radical or
C.sub.7-C.sub.12 aralkylene radical; R.sub.15 and R.sub.15',
independently of each other, are hydrogen, C.sub.1-C.sub.4 alkyl or
halogen; and Q is a radical of formula (5) 11wherein r is the
number 0 or 1, each of R.sub.16 and R.sub.17 independently of the
other is hydrogen, C.sub.1-C.sub.4 alkyl, phenyl, carboxy or
halogen, R.sub.18 is hydrogen, C.sub.1-C.sub.4 alkyl or halogen,
and Z' is a linear or branched C.sub.1-C.sub.12 alkylene, an
unsubstituted phenylene, an C.sub.1-C.sub.4 alkyl- or
C.sub.1-C.sub.4 alkoxy-substituted phenylene, or a C.sub.7-C.sub.12
aralkylene.
14. A polymerizable material of claim 13, wherein component (a)
consists of one or more pblyalkylene glycols of formula (1a)
HO--(CH.sub.2--CH.sub.2--O).sub.n--(CHY.sub.1--CHY.sub.2--O).sub.m--H
(1a) wherein one of radicals Y.sub.1 and Y.sub.2 signifies methyl
and the other radical signifies hydrogen, and n and m,
independently of one another, each denote a number from 0 to 50,
wherein the sum of (n+m) is 8 to 50, wherein component (b) consists
of one or more linear or branched aliphatic polyhydroxy compounds
of formula (2), in which x is a number from 3 to 8, wherein
component (c) consists of one or more diisocyanates of formula (3a)
OCN--R.sub.5--NCO (3a) wherein R.sub.5 is a linear or branched
C.sub.3-C.sub.18-alkylene, an unsubstituted or
C.sub.1-C.sub.4-alkyl-substituted or
C.sub.1-C.sub.4-alkoxy-substituted C.sub.6-C.sub.10-arylene, a
C.sub.7-C.sub.18-aralkylene, a
C.sub.6-C.sub.10-arylene-C.sub.1-C.sub.2-alkylene-C.sub.6-C.sub.10-arylen-
e, a C.sub.3-C.sub.8-cyclo-alkylene, a
C.sub.3-C.sub.8-cycloalkylene-C.sub- .1-C.sub.6-alkylene, a
C.sub.3-C.sub.8-cycloalkylene-C.sub.1-C.sub.2-alkyl-
ene-C.sub.3-C.sub.8-cycloalkylene, or a
C.sub.1-C.sub.6-alkylene-C.sub.3-C-
.sub.8-cycloalkylene-C.sub.1-C.sub.6-alkylene, wherein said
ethylenically unsaturated amine is selected from the group
consisting of mono-C.sub.1-C.sub.4 alkylamino-C.sub.1-C.sub.4
alkyl-acrylates, mono-C.sub.1-C.sub.4 alkylamino-C.sub.1-C.sub.4
alkyl-methacrylates, di-C.sub.1-C.sub.4 alkylamino-C.sub.1-C.sub.4
alkyl-acrylates and di-C.sub.1-C.sub.4 alkylamino-C.sub.1-C.sub.4
alkyl-methacrylates, and wherein said ethylenically unsaturated
hydroxy compound is selected from the group consisting of
hydroxy-substituted C.sub.1-C.sub.6 alkylacrylates and
hydroxy-substituted C.sub.1-C.sub.6 alkylmethacrylates.
15. A polymerizable material of claim 14, wherein said
ethylenically unsaturated amine is 2-terbutylaminoethylmethacrylate
or 2-terbutylaminoethylacrylate, wherein said ethylenically
unsaturated hydroxy compound is 2-hydroxyethylmethacrylate or
2-hydroxyehtylcrylate, wherein component (c) consists of a
diisocyanate selected from the group consisting isophorone
diisocyanate (IPDI), toluylene-2,4-diisocyanate (TDI),
methylenebis(cyclohexyl-isocyanate), 1,6-diisocyanato-2,2,4-trimet-
hyl-n-hexane (TMDI), methylenebis(phenyl-isocyanate) and
hexamethylene-diisocyanate (HMDI).
16. A polymeric article obtained by curing a polymerizable material
of claim 2 in a mold.
17. A polymeric article of claim 16, wherein said polymeric article
is an ophthalmic device.
18. An ophthalmic device of claim 17, wherein said ophthalmic
device is a contact lens.
19. A contact lens of claim 18, wherein said water-soluble
polyvinyl alcohol is a polyhydroxyl compound which has a weight
average molecular weight of at least about 2000 and which comprises
from about 0.5 to about 80%, based on the number of hydroxyl groups
in the poly(vinyl alcohol), of units of the formula I, I and II, I
and III, or I and II and III 12in which R is alkylene having up to
12 carbon atoms, R.sub.1 is hydrogen or lower alkyl, R.sub.2 is an
olefinically unsaturated, electron-withdrawing, crosslinkable
radical having up to 25 carbon atoms, and R.sub.3 is hydrogen, a
C.sub.1-C.sub.6 alkyl group or a cycloalkyl group, 13wherein R and
R.sub.3 are as defined above, and R.sub.7 is a primary, secondary
or tertiary amino group or a quaternary amino group of the formula
N.sup.+(R').sub.3X.sup.-, in which each R', independently of the
others, is hydrogen or a C.sub.1-C.sub.4 alkyl radical and X is
HSO.sub.4.sup.-, F--, Cl.sup.-, Br.sup.-, I.sup.-,
CH.sub.3COO.sup.-, OH.sup.-, BF.sup.-, or H.sub.2PO.sub.4.sup.-,
14in which R and R.sub.3 are as defined above, and R.sub.8 is the
radical of a monobasic, dibasic or tribasic, saturated or
unsaturated, aliphatic or aromatic organic acid or sulfonic
acid.
20. A contact lens of claim 19, wherein said water-soluble
polyvinyl alcohol is a polyhydroxyl compound which has a molecular
weight of at least about 2000 and which comprises from about 0.5 to
about 80%, based on the number of hydroxyl groups in the poly(vinyl
alcohol), of units of the formula I, wherein R.sub.2 is a radical
of formula IV or formula V
--CO--NH--(R.sub.5--NH--CO--O).sub.q--R.sub.6--O--CO--R.sub.4 (IV)
--[CO--NH--(R.sub.5--NH--CO--O).sub.q--R.sub.6--O].sub.p--CO--R.sub.4
(V) in which p and q, independently of one another, are zero or
one, and R.sub.5 and R.sub.6, independently of one another, are
lower alkylene having 2 to 8 carbon atoms, arylene having 6 to 12
carbon atoms, a saturated bivalent cycloaliphatic group having 6 to
10 carbon atoms, arylenealkylene or alkylenearylene having 7 to 14
carbon atoms or arylenealkylenearylene having 13 to 16 carbon
atoms, and in which R.sub.4 is an olefinically unsaturated
copolymerizable radical having 2 to 24 carbone atoms, preferably
having 2 to 8 carbonatoms, more preferably having 2 to 4 carbon
atoms.
21. A contact lens of claim 19, wherein said modifier is composed
of the nanopaticles having a hydrophilic surface.
22. A contact lens of claim 21, wherein the nanoparticles are
nano-sized silica fillers.
23. A contact lens of claim 19, wherein said modifier is composed
of one or more copolymers each having hydrophobic groups or units
for imparting at least one desired physical property to said
ophthalmic device and hydrophilic groups or units in an amount
sufficient to render the copolymer miscible with the crosslinkable
polyvinyl alcohol.
24. A contact lens of claim 23, wherein said modifier is a N-vinyl
lactam copolymer which is a copolymerization product of at least
one N-vinyl lactam with one or more hydrophobic monomer, wherein
said at least one N-vinyl lactam has a structure of formula (VI)
15in which R.sub.1 g is an alkylene di-radical having from 2 to 8
carbon atoms, R.sub.20 is hydrogen, C.sub.1-C.sub.7 alkyl, aryl
having up to 10 carbon atoms, aralkyl or alkaryl having up to 14
carbon atoms, and R.sub.21 is hydrogen or lower alkyl having up to
7 carbon atoms.
25. A contact lens of claim 24, wherein said N-vinyl lactam is
N-vinyl pyrrolidone.
26. A contact lens of claim 23, wherein said modifier is a
N,N-dialkylmethacrylamide copolymer which is a copolymerization
product of a N,N-di-C.sub.2-C.sub.4 alkyl methacrylamide with at
least one hydrophobic monomer.
27. A contact lens of claim 26, wherein the N,N-di-C.sub.2-C.sub.4
alkyl methacrylamide is N,N-dimethylmethacrylamide.
28. A contact lens of claim 23, wherein said modifier is a
non-crosslinkable polyurethane having a molecular weight of at
least about 2000, or a crosslinkable polyurethane.
29. A contact lens of claim 28, wherein said non-crosslinkable
polyurethane is the reaction product of an isocyanate-capped
polyurethane with water and amine, wherein said crosslinkable
polyurethane is the reaction product of the isocyanate-capped
polyurethane with an ethylenically unsaturated amine (primary or
secondary amine) or an ethylenically unsaturated monohydroxy
compound, wherein said isocyanate-capped polyurethane is a
copolymerization product of (a) at least one polyalkylene glycol of
formula HO--(R.sub.9--O).sub.n--(R.sub.1-
0--O).sub.m--(R.sub.11--O).sub.l--H (1) wherein R.sub.9, R.sub.10,
and R.sub.11, independently of one other, are each linear or
branched C.sub.2-C.sub.4-alkylene, and n, m and 1, independently of
one another, are each a number from 0 to 100, wherein the sum of
(n+m+l) is 5 to 100, (b) at least one branching agent selected from
the group consisting of (i) a linear or branched aliphatic
polyhydroxy compound of formula R.sub.12--(OH).sub.x (2), wherein
R.sub.12 is a linear or branched C.sub.3-C.sub.18 aliphatic
multi-valent radical and x is a number .gtoreq.3, (ii) a polyether
polyol, which is the polymerization product of a compound of
formula (2) and a glycol, (iii) a polyester polyol, which is the
polymerization product of a compound of formula (2), a dicarboxylic
acid or a derivative thereof and a diol, and (iv) a cycloaliphatic
polyol selected from the group consisting of a
C.sub.5-C.sub.8-cycloalkane which is substituted by .gtoreq.3
hydroxy groups and which is unsubstituted by alkyl radical, a
C.sub.5-C.sub.9-cycloalkane which is substituted by .gtoreq.3
hydroxy groups and which is substituted by one ore more
C.sub.1-C.sub.4 alkyl radicals, and an unsubstituted mono- and
disaccharide, (v) an aralkyl polyol having at least three hydroxy
C.sub.1-C.sub.4 alkyl radicals, and (c) at least one di- or
polyisocyanate of formula R.sub.13--(NCO).sub.y (3) wherein
R.sub.13 the multivalent radical of a linear or branched
C.sub.3-C.sub.24 aliphatic polyisocyanate, the multivalent radical
of a C.sub.3-C.sub.24 cycloaliphatic or aliphatic-cycloaliphatic
polyisocyanate, or the multivalent radical of a C.sub.3-C.sub.24
aromatic or araliphatic polyisocyanate, and y is a number from 2 to
6, wherein said ethylenically unsaturated monohydroxy compound is a
hydroxy-substituted lower alkylacrylate, a hydroxy-substituted
lower alkylmethacrylate, a hydroxy-substituted lower
alkyl-acrylamides, a hydroxy-substituted lower
alkyl-methacrylamide, or a hydroxy-substituted lower
alkylvinylether, wherein said ethylenically unsaturated amine has
formula (4), (4') or (4") 16In which, l, j and k, independent of
one another, are o or 1; R.sub.14 is hydrogen, a linear or branched
C.sub.1-C.sub.24 alkyl, a C.sub.2-C.sub.24 alkoxyalkyl, a
C.sub.2-C.sub.24 alkylcarbonyl, a C.sub.2-C.sub.24 alkoxycarbonyl,
an unsubstituted or C.sub.1-C.sub.4 alkyl- or C.sub.1-C.sub.4
alkoxy-substituted C.sub.6-C.sub.10 aryl, a C.sub.7-C.sub.18
aralkyl, a C.sub.13-C.sub.22 arylalkylaryl, a C.sub.3-C.sub.8
cycloalkyl, a C.sub.4-C.sub.14 cycloalkylalkyl, a C.sub.7-C.sub.18
cycloalkylalkylcycloalkyl, a C.sub.5-C.sub.20 alkylcycloalkylalkyl,
or an aliphatic-heterocyclic radical; Z is a C.sub.1-C.sub.1-2
alkylene radical, phenylene radical or C.sub.7-C.sub.12 aralkylene
radical; R.sub.15 and R.sub.15', independently of each other, are
hydrogen, C.sub.1-C.sub.4 alkyl or halogen; and Q is a radical of
formula (5) 17wherein r is the number 0 or 1, each of R.sub.16 and
R.sub.17 independently of the other is hydrogen, C.sub.1-C.sub.4
alkyl, phenyl, carboxy or halogen, R.sub.18 is hydrogen,
C.sub.1-C.sub.4 alkyl or halogen, and Z' is a linear or branched
C.sub.1-C.sub.1-2 alkylene, an unsubstituted phenylene, an
C.sub.1-C.sub.4 alkyl- or C.sub.1-C.sub.4 alkoxy-substituted
phenylene, or a C.sub.7-C.sub.12 aralkylene.
30. A contact lens of claim 29, wherein component (a) consists of
one or more polyalkylene glycols of formula (Ia)
HO--(CH.sub.2--CH.sub.2--O).sub-
.n--(CHY.sub.1--CHY.sub.2--O).sub.m--H (1a) wherein one of radicals
Y.sub.1 and Y.sub.2 signifies methyl and the other radical
signifies hydrogen, and n and m, independently of one another, each
denote a number from 0 to 50, wherein the sum of (n+m) is 8 to 50,
wherein component (b) consists of one or more linear or branched
aliphatic polyhydroxy compounds of formula (2), in which x is a
number from 3 to 8, wherein component (c) consists of one or more
diisocyanates of formula (3a) OCN--R.sub.5--NCO (3a) wherein
R.sub.5 is a linear or branched C.sub.3-C.sub.18-alkylene, an
unsubstituted or C.sub.1-C.sub.4-alkyl-subs- tituted or
C.sub.1-C.sub.4-alkoxy-substituted C.sub.6-C.sub.10-arylene, a
C.sub.7-C.sub.18-aralkylene, a
C.sub.6-C.sub.10-arylene-C.sub.1-C.sub.2-a-
lkylene-C.sub.6-C.sub.10-arylene, a C.sub.3-C.sub.8-cyclo-alkylene,
a C.sub.3-C.sub.8-cycloalkylene-C.sub.1-C.sub.6-alkylene, a
C.sub.3-C.sub.8-cycloalkylene-C.sub.1-C.sub.2-alkylene-C.sub.3-C.sub.8-cy-
cloalkylene, or a
C.sub.1-C.sub.6-alkylene-C.sub.3-C.sub.8-cycloalkylene-C-
.sub.1-C.sub.6-alkylene, wherein said ethylenically unsaturated
amine is selected from the group consisting of mono-C.sub.1-C.sub.4
alkylamino-C.sub.1-C.sub.4 alkyl-acrylates, mono-C.sub.1-C.sub.4
alkylamino-C.sub.1-C.sub.4 alkyl-methacrylates, di-C.sub.1-C.sub.4
alkylamino-C.sub.1-C.sub.4 alkyl-acrylates and di-C.sub.1-C.sub.4
alkylamino-C.sub.1-C.sub.4 alkyl-methacrylates, and wherein said
ethylenically unsaturated hydroxy compound is selected from the
group consisting of hydroxy-substituted C.sub.1-C.sub.6
alkylacrylates and hydroxy-substituted C.sub.1-C.sub.6
alkylmethacrylates.
31. A contact lens of claim 30, wherein said ethylenically
unsaturated amine is 2-terbutylaminoethylmethacrylate or
2-terbutylaminoethylacrylate- , wherein said ethylenically
unsaturated hydroxy compound is 2-hydroxyethylmethacrylate or
2-hydroxyehtylcrylate, wherein component (c) consists of a
diisocyanate selected from the group consisting isophorone
diisocyanate (IPDI), toluylene-2,4-diisocyanate (TD I),
methylenebis(cyclohexyl-isocyanate),
1,6-diisocyanato-2,2,4-trimethyl-n-h- exane (TMDI),
methylenebis(phenyl-isocyanate) and hexamethylene-diisocyana- te
(HMDI).
32. A method for making an ophthalmic device, comprising the steps
of: (I) introducing a polymerizable material comprising a
water-soluble polyvinyl alcohol having crosslinkable groups, a
modifier in an amount sufficient to improve one or more physical
properties of the ophthalmic device made from the polymerizable
material, and optionally a photo-initiator, into a mold, wherein
said modifier is selected from the group consisting of
nanoparticles having a hydrophilic surface, a copolymer having
hydrophobic groups or units for imparting at least one desired
physical property to said ophthalmic device and hydrophilic groups
or units in an amount sufficient to render the copolymer miscible
with the polyvinyl alcohol, and mixtures thereof, wherein the one
or more physical properties are selected from the group consisting
of stress at break (N/mm.sup.2), percentage of elongation at break,
toughness or energy to break (N.multidot.mm), and susceptibility to
fracture; (II) crosslinking by actinic radiation the polymerizable
material; and (III) opening the mold so that the ophthalmic device
can be removed from the mold.
33. A method of claim 32, wherein said water-soluble polyvinyl
alcohol is a polyhydroxyl compound which has a weight average
molecular weight of at least about 2000 and which comprises from
about 0.5 to about 80%, based on the number of hydroxyl groups in
the poly(vinyl alcohol), of units of the formula I, I and II, I and
III, or I and II and III 18in which R is alkylene having up to 12
carbon atoms, R.sub.1 is hydrogen or lower alkyl, R.sub.2 is an
olefinically unsaturated, electron-withdrawing, crosslinkable
radical having up to 25 carbon atoms, and R.sub.3 is hydrogen, a
C.sub.1-C.sub.6 alkyl group or a cycloalkyl group, 19wherein R and
R.sub.3 are as defined above, and R.sub.7 is a primary, secondary
or tertiary amino group or a quaternary amino group of the formula
N.sup.+(R').sub.3X.sup.-, in which each R', independently of the
others, is hydrogen or a C.sub.1-C.sub.4 alkyl radical and X is
HSO.sub.4.sup.-, F.sup.-, Cl.sup.-, Br.sup.-, I.sup.-,
CH.sub.3COO.sup.-, OH.sup.-, BF.sup.-, or H.sub.2PO.sub.4-, 20in
which R and R.sub.3 are as defined above, and R.sub.8 is the
radical of a monobasic, dibasic or tribasic, saturated or
unsaturated, aliphatic or aromatic organic acid or sulfonic
acid.
34. A method of claim 33, wherein said modifier is composed of the
nanopaticles having a hydrophilic surface.
35. A method of claim 33, wherein said modifier is composed of one
or more copolymers each having hydrophobic groups or units for
imparting at least one desired physical property to said ophthalmic
device and hydrophilic groups or units in an amount sufficient to
render the copolymer miscible with the crosslinkable polyvinyl
alcohol.
36. A method of claim 35, wherein said modifier is a N-vinyl lactam
copolymer which is a copolymerization product of at least one
N-vinyl lactam with one or more hydrophobic monomer, wherein said
at least one N-vinyl lactam has a structure of formula (VI) 21in
which R.sub.19 is an alkylene di-radical having from 2 to 8 carbon
atoms, R.sub.20 is hydrogen, C.sub.1-C.sub.7 alkyl, aryl having up
to 10 carbon atoms, aralkyl or alkaryl having up to 14 carbon
atoms, and R.sub.21 is hydrogen or lower alkyl having up to 7
carbon atoms.
37. A method of claim 35, wherein said modifier is a
N,N-dialkylmethacrylamide copolymer which is a copolymerization
product of a N,N-di-C.sub.2-C.sub.4 alkyl methacrylamide with at
least one hydrophobic monomer.
38. A method of claim 35, wherein said modifier is a
non-crosslinkable polyurethane having a molecular weight of at
least about 2000, or a crosslinkable polyurethane.
39. A method of claim 38, wherein said non-crosslinkable
polyurethane is the reaction product of an isocyanate-capped
polyurethane with water and amine, wherein said crosslinkable
polyurethane is the reaction product of the isocyanate-capped
polyurethane with an ethylenically unsaturated amine (primary or
secondary amine) or an ethylenically unsaturated monohydroxy
compound, wherein said isocyanate-capped polyurethane is a
copolymerization product of (a) at least one polyalkylene glycol of
formula
HO--(R.sub.9--O).sub.n--(R.sub.10--O).sub.m--(R.sub.11--O).sub.l--
-H (1) wherein R.sub.9, R.sub.10, and R.sub.11, independently of
one other, are each linear or branched C.sub.2-C.sub.4-alkylene,
and n, m and l, independently of one another, are each a number
from 0 to 100, wherein the sum of (n+m+l) is 5 to 100, (b) at least
one branching agent selected from the group consisting of (i) a
linear or branched aliphatic polyhydroxy compound of formula
R.sub.12--(OH).sub.x (2), wherein R.sub.12 is a linear or branched
C.sub.3-C.sub.18 aliphatic multi-valent radical and x is a number
.gtoreq.3, (ii) a polyether polyol, which is the polymerization
product of a compound of formula (2) and a glycol, (iii) a
polyester polyol, which is the polymerization product of a compound
of formula (2), a dicarboxylic acid or a derivative thereof and a
diol, and (iv) a cycloaliphatic polyol selected from the group
consisting of a C.sub.5-C.sub.8-cycloalkane which is substituted by
.gtoreq.3 hydroxy groups and which is unsubstituted by alkyl
radical, a C.sub.5-C.sub.8-cycloalkane which is substituted by
.gtoreq.3 hydroxy groups and which is substituted by one ore more
C.sub.1-C.sub.4 alkyl radicals, and an unsubstituted mono- and
disaccharide, (v) an aralkyl polyol having at least three hydroxy
C.sub.1-C.sub.4 alkyl radicals, and (c) at least one di- or
polyisocyanate of formula R.sub.13--(NCO).sub.y (3) wherein
R.sub.13 the multivalent radical of a linear or branched
C.sub.3-C.sub.24 aliphatic polyisocyanate, the multivalent radical
of a C.sub.3-C.sub.24 cycloaliphatic or aliphatic-cycloaliphatic
polyisocyanate, or the multivalent radical of a C.sub.3-C.sub.24
aromatic or araliphatic polyisocyanate, and y is a number from 2 to
6, wherein said ethylenically unsaturated monohydroxy compound is a
hydroxy-substituted lower alkylacrylate, a hydroxy-substituted
lower alkylmethacrylate, a hydroxy-substituted lower
alkyl-acrylamides, a hydroxy-substituted lower
alkyl-methacrylamide, or a hydroxy-substituted lower
alkylvinylether, wherein said ethylenically unsaturated amine has
formula (4), (4') or (4") 22In which, l, j and k, independent of
one another, are o or 1; R.sub.14 is hydrogen, a linear or branched
C.sub.1-C.sub.24 alkyl, a C.sub.2-C.sub.24 alkoxyalkyl, a
C.sub.2-C.sub.24 alkylcarbonyl, a C.sub.2-C.sub.24 alkoxycarbonyl,
an unsubstituted or C.sub.1-C.sub.4 alkyl- or C.sub.1-C.sub.4
alkoxy-substituted C.sub.6-C.sub.10 aryl, a C.sub.7-C.sub.18
aralkyl, a C.sub.13-C.sub.22 arylalkylaryl, a C.sub.3-C.sub.8
cycloalkyl, a C.sub.4-C.sub.14cycloalkylalkyl, a C.sub.7-C.sub.18
cycloalkylalkylcycloalkyl, a C.sub.5-C.sub.20 alkylcycloalkylalkyl,
or an aliphatic-heterocyclic radical; Z is a C.sub.1-C.sub.1-2
alkylene radical, phenylene radical or C.sub.7-C.sub.12 aralkylene
radical; R.sub.15 and R.sub.15', independently of each other, are
hydrogen, C.sub.1-C.sub.4 alkyl or halogen; and Q is a radical of
formula (5) 23wherein r is the number 0 or 1, each of R.sub.16 and
R.sub.17 independently of the other is hydrogen, C.sub.1-C.sub.4
alkyl, phenyl, carboxy or halogen, R.sub.18 is hydrogen,
C.sub.1-C.sub.4 alkyl or halogen, and Z' is a linear or branched
C.sub.1-C.sub.1-2 alkylene, an unsubstituted phenylene, an
C.sub.1-C.sub.4 alkyl- or C.sub.1-C.sub.4 alkoxy-substituted
phenylene, or a C.sub.7-C.sub.12 aralkylene.
40. A method of claim 39, wherein component (a) consists of one or
more polyalkylene glycols of formula (Ia)
HO--(CH.sub.2--CH.sub.2--O).sub.n--(-
CHY.sub.1--CHY.sub.2--O).sub.m--H (1a) wherein one of radicals
Y.sub.1 and Y.sub.2 signifies methyl and the other radical
signifies hydrogen, and n and m, independently of one another, each
denote a number from 0 to 50, wherein the sum of (n+m) is 8 to 50,
wherein component (b) consists of one or more linear or branched
aliphatic polyhydroxy compounds of formula (2), in which x is a
number from 3 to 8, wherein component (c) consists of one or more
diisocyanates of formula (3a) OCN--R.sub.5--NCO (3a) wherein
R.sub.5 is a linear or branched C.sub.3-C.sub.1-8-alkylene, an
unsubstituted or C.sub.1-C.sub.4-alkyl-substituted or
C.sub.1-C.sub.4-alkoxy-substituted C.sub.6-C.sub.10-arylene, a
C.sub.7-C.sub.18-aralkylene, a
C.sub.6-C.sub.10-arylene-C.sub.1-C.sub.2-a-
lkylene-C.sub.6-C.sub.10-arylene, a C.sub.3-C.sub.8-cyclo-alkylene,
a C.sub.3-C.sub.8-cycloalkylene-C.sub.1-C.sub.6-alkylene, a
C.sub.3-C.sub.8-cycloalkylene-C.sub.1-C.sub.2-alkylene-C.sub.3-C.sub.8-cy-
cloalkylene, or a
C.sub.1-C.sub.6-alkylene-C.sub.3-C.sub.8-cycloalkylene-C-
.sub.1-C.sub.6-alkylene, wherein said ethylenically unsaturated
amine is selected from the group consisting of mono-C.sub.1-C.sub.4
alkylamino-C.sub.1-C.sub.4 alkyl-acrylates, mono-C.sub.1-C.sub.4
alkylamino-C.sub.1-C.sub.4 alkyl-methacrylates,
di-C.sub.1-C.sub.4alkylam- ino-C.sub.1-C.sub.4alkyl-acrylates and
di-C.sub.1-C.sub.4alkylamino-C.sub.- 1-C.sub.4 alkyl-methacrylates,
and wherein said ethylenically unsaturated hydroxy compound is
selected from the group consisting of hydroxy-substituted
C.sub.1-C.sub.6 alkylacrylates and hydroxy-substituted
C.sub.1-C.sub.6 alkylmethacrylates.
41. A method of claim 40, wherein said ethylenically unsaturated
amine is 2-terbutylaminbethylmethacrylate or
2-terbutylaminoethylacrylate, wherein said ethylenically
unsaturated hydroxy compound is 2-hydroxyethylmethacrylate or
2-hydroxyehtylcrylate, wherein component (c) consists of a
diisocyanate selected from the group consisting isophorone
diisocyanate (IPDI), toluylene-2,4-diisocyanate (TDI),
methylenebis(cyclohexyl-isocyanate),
1,6-diisocyanato-2,2,4-trimethyl-n-h- exane (TMDI),
methylenebis(phenyl-isocyanate) and hexamethylene-diisocyana- te
(HMDI).
42. A method for modifying one or more physical properties of a
hydrogel article obtained from the polymerization of a
crosslinkable polymer, comprising the steps of: (I) adding, into a
solution of said crosslinkable polymer, a modifier in an amount
sufficient to modify said one or more physical properties of said
polymeric article, wherein said modifier is selected from the group
consisting of nanoparticles having a hydrophilic surface, a
copolymer having hydrophobic groups or units for imparting at least
one desired physical property to said hydrogel article and
hydrophilic groups or units in an amount sufficient to render it
miscible with the crosslinkable polymer, and mixtures thereof; (II)
mixing thoroughly said modifier and the crosslinkable polymer; and
(III) crosslinking said crosslinkable polymer in the presence of
the modifier to obtain said hydrogel article, wherein the one or
more physical properties are selected from the group consisting of
stress at break (N/mm.sup.2), percentage of elongation at break,
toughness or energy to break (N.multidot.mm), and susceptibility to
fracture.
43. A method of claim 42, wherein said modifier is composed of the
nanopaticles having a hydrophilic surface.
44. A method of claim 43, wherein said modifier is composed of the
nanopaticles having a hydrophilic surface.
45. A method of claim 42, wherein said modifier is composed of one
or more copolymers each having hydrophobic groups or units for
imparting at least one desired physical property to said ophthalmic
device and hydrophilic groups or units in an amount sufficient to
render the copolymer miscible with the crosslinkable polymer.
46. A method of claim 35, wherein each of said one or more
copolymers is a polymerization product of at least one hydrophilic
monomer and at least one hydrophobic monomer, wherein said
hydrophilic is present in an amount sufficient to impart a desired
miscibility with the crosslinkable polymer.
Description
[0001] This application claims the benefit under USC .sctn.119)e)
of U.S. provisional application No. 60/420,626 filed Oct. 23, 2002,
and is incorporated by reference in it's entirety.
[0002] The present invention is related to polymerizable materials
useful for making polymeric articles, preferably ophthalmic
devices, more preferably soft contact lenses. In particular, the
present invention is related to a composition comprising a
water-soluble, crosslinkable polyvinyl alchohol with crosslinkable
groups and a modifier capable of imparting at least one desired
physical property of an ophthalmic device made from the
composition. The present invention is also related to a method for
making a polymeric article, preferably ophthalmic devices, more
preferably soft contact lenses from polymerizable materials of the
invention. In addition, the present invention is related to a
method for preparing a polymeric article having at least one
desired physical property.
BACKGROUND
[0003] It is well known that contact lenses can be used for
cosmetics and the correction of visual acuity. The ideal contact
lens is one which is not only comfortable to wear for extended
periods of time, but also easily and reproducibly manufactured at
minimum cost in time and labor.
[0004] Contact lenses can be manufactured economically in large
numbers by the so-called mold or full-mold process. Known contact
lens-molding processes are described in, for example, PCT patent
application no. WO/87/04390 or in EP-A 0 367 513. In a typical
molding process, a predetermined amount of a polymerizable or
crosslinkable material is placed in the female mold half and the
mold is closed by placing the male mold half proximately to the
female mold half to create a cavity having a desired geometry for a
contact lens. Normally, a surplus of polymerizable or crosslinkable
material is used so that when the male and female halves of the
mold are closed, the excess amount of the material is expelled out
into an overflow area adjacent to the mold cavity. The
polymerizable or crosslinkable material remaining within the mold
is polymerized or cross-linked with the delivery of radiation
thereto through UV light, heat action, or another non-thermal
methods. Since the geometry of the ophthalmic lens is specifically
defined by the cavity between the male and female mold halves and
since the geometry of the edge of the ophthalmic lens is defined by
the contour of the two mold halves in the area where they make
contact, a contact lens is manufactured into a final form between
typically male and female mold halves, with no additional finishing
work on the surface of the lens or the edges of the lens. Such
full-mold process can reduce cost in the production of contact
lenses. However, in a typical molding process, a contact lens,
which is removed from the mold after curing, needs to undergo the
other manufacturing processes such as hydration/extraction and
sterilization. Therefore, there is still room for further reducing
manufacturing cost of contact lenses.
[0005] U.S. Pat. Nos. 5,508,317, 5,583,463, 5,789,464, and
5,849,810 describe an improved manufacturing process for
economically producing contact lenses in large numbers. By using a
prepolymer which is a water-soluble photo-crosslinkable polyvinyl
alcohol, a finished lens of optical quality can be produced in a
mold within a few seconds without the necessity for subsequent
extraction or finishing steps to the contact lens. With such
manufacturing process, contact lenses can be manufactured at
considerably low cost and thus it is possible to produce disposable
contact lenses that are discarded by the user after a single
use.
[0006] Although contact lenses manufactured by one of the processes
disclosed by U.S. Pat. Nos. 5,508,317, 5,583,463, 5,789,464, and
5,849,810 have advantageous properties such as a good compatibility
with the human cornea resulting in a relatively high wearing
comfort and the absence of irritation and allergenic effects, a
need for further improvement still remains. For example, problems
may sometimes show up in production of contact lenses from a
water-soluble photo-crosslinkable polyvinyl alcohol. In particular,
during mold opening and removing the contact lenses from the mold,
cracks, flaws or tears may occur in the lenses or in the worst case
the contact lenses even break totally. Contact lenses having such
defects have to be discarded and lower the overall production
yield. In addition, contact lenses made from a water-soluble
photo-crosslinkable polyvinyl alcohol do not always posses all of
most desirable physical properties, for example, such as elasticity
and durability, for the intended uses.
[0007] One object of the invention is to provide a polymerizable
composition useful for economically producing soft contact lenses
having improved durability, elasticity and/or other desired
physical properties.
[0008] Another object of the invention is to provide an improved
method for economically producing soft contact lenses having
improved durability, elasticity and/or other desired physical
properties.
SUMMARY OF THE INVENTION
[0009] In accomplishing the foregoing, there is provided, in
accordance with one aspect of the present invention, a
polymerizable material for making a polymeric article, the
polymerizable material comprising: a water-soluble polyvinyl
alcohol having crosslinkable groups; and a modifier in an amount
sufficient to improve one or more physical properties of a
polymeric article made from the polymerizable material, wherein the
one or more physical properties are selected from the group
consisting of stress at break (N/mm.sup.2), percentage of
elongation at break, toughness or energy to break (N.multidot.mm),
and susceptibility to fracture.
[0010] In another aspect, the present invention provides a
polymeric article which is a product of radiation-crosslinking of
an above-described polymerizable material of the invention in the
presence or preferably in the absence of one or more additional
vinylic monomers.
[0011] In a further aspect, the present invention provides an
ophthalmic device, preferably a soft contact lens, which is
obtained by crosslinking an above-described polymerizable material
of the invention in the presence or preferably in the absence of
one or more additional vinylic monomers.
[0012] In another further aspect, the present invention provides a
method for producing an ophthalmic device, the method comprising
the steps of: a) introducing an above-described polymerizable
material of the invention, in the presence or preferably in the
absence of one or more additional vinylic comonomers, and
optionally in the presence of a photo-initiator, into a mold; b)
crosslinking by actinic radiation the polymerizable material, and
c) opening the mold so that the ophthalmic device can be removed
from the mold.
[0013] In still a further aspect, the present invention provides a
method for modifying one or more physical properties of a hydrogel
article obtained from the polymerization of a crosslinkable
polymer, the method comprising the steps of: adding, into a
solution of said crosslinkable polymer, a modifier in an amount
sufficient to modify said one or more physical properties of said
polymeric article, wherein said modifier is selected from the group
consisting of nanoparticles having a hydrophilic surface, a
copolymer having hydrophobic groups or units for imparting at least
one desired physical property to said hydrogel article and
hydrophilic groups or units in an amount sufficient to render it
miscible with the crosslinkable polymer, and mixtures thereof;
mixing thoroughly said modifier and the crosslinkable polymer; and
crosslinking said crosslinkable polymer in the presence of the
modifier to obtain said hydrogel article, wherein the one or more
physical properties are selected from the group consisting of
stress at break (N/mm.sup.2), percentage of elongation at break,
toughness or energy to break (N.multidot.mm), and susceptibility to
fracture.
[0014] These and other aspects of the invention will become
apparent from the following description of the preferred
embodiments. As would be obvious to one skilled in the art, many
variations and modifications of the invention may be effected
without departing from the spirit and scope of the novel concepts
of the disclosure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Reference now will be made in detail to the embodiments of
the invention. It will be apparent to those skilled in the art that
various modifications and variations can be made in the present
invention without departing from the scope or spirit of the
invention. For instance, features illustrated or described as part
of one embodiment, can be used on another embodiment to yield a
still further embodiment. Thus, it is intended that the present
invention cover such modifications and variations as come within
the scope of the appended claims and their equivalents. Other
objects, features and aspects of the present invention are
disclosed in or are obvious from the following detailed
description. It is to be understood by one of ordinary skill in the
art that the present discussion is a description of exemplary
embodiments only, and is not intended as limiting the broader
aspects of the present invention.
[0016] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs.
Generally, the nomenclature used herein and the laboratory
procedures are well known and commonly employed in the art.
Conventional methods are used for these procedures, such as those
provided in the art and various general references. Where a term is
provided in the singular, the inventors also contemplate the plural
of that term. The nomenclature used herein and the laboratory
procedures described below are those well known and commonly
employed in the art.
[0017] In one aspect, the present invention relates to a
polymerizable material for making an ophthalmic device, preferably
a contact lens. A polymerizable material of the invention
comprises: a water-soluble polyvinyl alcohol having crosslinkable
groups; and a modifier in an amount sufficient to improve one or
more physical properties of a polymeric article made from the
polymerizable material, wherein the one or more physical properties
are selected from the group consisting of stress at break
(N/mm.sup.2), percentage of elongation at break, toughness or
energy to break (N.multidot.mm), and susceptibility to
fracture.
[0018] "Improvement in the stress at break (N/mm.sup.2) of an
ophthalmic device" means that the ophthalmic device, prepared from
a composition composed of a water-soluble polyvinyl alcohol having
crosslinkable groups and a modifier, has an increased value of the
stress at break relative to an ophthalmic device prepared from a
composition composed of a water-soluble polyvinyl alcohol without
the modifier.
[0019] "Improvement in the percentage of elongation at break, of an
ophthalmic device" means that the ophthalmic device, prepared from
a composition composed of a water-soluble polyvinyl alcohol having
crosslinkable groups and a modifier, has an increased value of
percentage of elongation at break relative to an ophthalmic device
prepared from a composition composed of a water-soluble polyvinyl
alcohol without the modifier.
[0020] "Improvement in the toughness or energy to break
(N.multidot.mm) of an ophthalmic device" means that the ophthalmic
device, prepared from a composition composed of a water-soluble
polyvinyl alcohol having crosslinkable groups and a modifier, has
an increased value of the toughness or energy to break
(N.multidot.mm) relative to an ophthalmic device prepared from a
composition composed of a water-soluble polyvinyl alcohol without
the modifier.
[0021] "Improvement in susceptibility to fracture of an ophthalmic
device" means that the ophthalmic device, prepared from a
composition composed of a water-soluble polyvinyl alcohol having
crosslinkable groups and a modifier, is less susceptible to
fracture relative to an ophthalmic device prepared from a
composition composed of a water-soluble polyvinyl alcohol without
the modifier.
[0022] An "ophthalmic device", as used herein, refers to a contact
lens (hard or soft), an intraocular lens, a corneal onlay, and
other ophthalmic devices (e.g., stents, implants, or the like) used
on or about the eye or ocular vicinity. An ophthalmic device
according to the invention is preferably a soft contact lens, more
preferably a hydrogel contact lens.
[0023] A "crosslinkable group", as used herein, refer to a
photocrosslinkable or thermally crosslinkable group well known to
the person skilled in the art. Crosslinkable groups such as those
already proposed for the preparation of contact lens materials are
especially suitable. Those include especially, but not exclusively,
groups comprising carbon-carbon double bonds.
[0024] A "radiation-curable prepolymer" refers to a starting
polymer which can be crosslinked upon actinic radiation to obtain a
crosslinked polymer having a molecular weight much higher than the
starting polymer. Examples of actinic radiation are UV irradiation,
ionized radiation (e.g. gamma ray or X-ray irradiation), microwave
irradiation, and the like.
[0025] A "hydrophilic vinylic monomer" refers to a monomer which as
a homopolymer typically yields a polymer that is water-soluble or
can absorb at least 10 percent by weight water.
[0026] A "hydrophobic vinylic monomer" refers to a monomer which as
a homopolymer typically yields a polymer that is insoluble in water
and can absorb less than 10 percent by weight water.
[0027] A water-soluble crosslinkable poly(vinyl alcohol) according
to the invention is preferably a polyhydroxyl compound which has a
molecular weight of at least about 2000 and which comprises from
about 0.5 to about 80%, based on the number of hydroxyl groups in
the poly(vinyl alcohol), of units of the formula I, II and II, I
and III, or I and II and III 1
[0028] A "molecular weight", as used herein, refers to a weight
average molecular weight, Mw, determined by gel permeation
chromatography, unless otherwise specified.
[0029] In formula I, II and III, R.sub.3 is hydrogen, a
C.sub.1-C.sub.6 alkyl group or a cycloalkyl group.
[0030] In formula I, II and III, R is alkylene having up to 12
carbon atoms, preferably up to 8 carbon atoms, and can be linear or
branched. Suitable examples include octylene, hexylene, pentylene,
butylene, propylene, ethylene, methylene, 2-propylene, 2-butylene
and 3-pentylene. Lower alkylene R preferably has up to 6,
particularly preferably up to 4 carbon atoms. Methylene and
butylene are particularly preferred.
[0031] In the formula I, R.sub.1 is hydrogen or lower alkyl having
up to seven, in particular up to four, carbon atoms. Most
preferably, R.sub.1 is hydrogen.
[0032] In the formula I, R.sub.2 is an olefinically unsaturated,
electron-withdrawing, crosslinkable radical, preferably having up
to 25 carbon atoms. In one embodiment, R.sub.2 is an olefinically
unsaturated acyl radical of the formula R.sub.4--CO--, in which
R.sub.4 is an olefinically unsaturated, crosslinkable radical
having 2 to 24 carbon atoms, preferably having 2 to 8 carbon atoms,
particularly preferably having 2 to 4 carbon atoms.
[0033] The olefinically unsaturated, crosslinkable radical R.sub.4
having 2 to 24 carbon atoms is preferably alkenyl having 2 to 24
carbon atoms, in particular alkenyl having 2 to 8 carbon atoms,
particularly preferably alkenyl having 2 to 4 carbon atoms, for
example ethenyl, 2-propenyl, 3-propenyl, 2-butenyl, hexenyl,
octenyl or dodecenyl. Ethenyl and 2-propenyl are preferred, so that
the --CO--R.sub.4 group is the acyl radical of acrylic acid or
methacrylic acid.
[0034] In another embodiment, the radical R.sub.2 is a radical of
the formula IV, preferably of the formula V
--CO--NH--(R.sub.5--NH--CO--O).sub.qR.sub.6--O--CO--R.sub.4
(IV)
--[CO--NH--(R.sub.5--NH--CO--O).sub.qR.sub.6--O].sub.p--CO--R.sub.4
(V)
[0035] in which p and q, independently of one another, are zero or
one, and R.sub.5 and R.sub.6, independently of one another, are
lower alkylene having 2 to 8 carbon atoms, arylene having 6 to 12
carbon atoms, a saturated bivalent cycloaliphatic group having 6 to
10 carbon atoms, arylenealkylene or alkylenearylene having 7 to 14
carbon atoms or arylenealkylenearylene having 13 to 16 carbon
atoms, and in which R.sub.4 is as defined above.
[0036] Lower alkylene R.sub.5 or R.sub.6 preferably has 2 to 6
carbon atoms and is, in particular, linear. Suitable examples
include propylene, butylene, hexylene, dimethylethylene and,
particularly preferably, ethylene.
[0037] Arylene R.sub.5 or R.sub.6 is preferably phenylene, which is
unsubstituted or substituted by lower alkyl or lower alkoxy, in
particular 1,3-phenylene or 1,4-phenylene or
methyl-1,4-phenylene.
[0038] A saturated bivalent cycloaliphatic group R.sub.5 or R.sub.6
is preferably cyclohexylene or cyclohexylene(lower alkylene), for
example cyclohexylenemethylene, which is unsubstituted or
substituted by one or more methyl groups, for example
trimethylcyclohexylenemethylene, for example the bivalent
isophorone radical.
[0039] The arylene unit of alkylenearylene or arylenealkylene
R.sub.5 or R.sub.6 is preferably phenylene, unsubstituted or
substituted by lower alkyl or lower alkoxy, and the alkylene unit
thereof is preferably lower alkylene, such as methylene or
ethylene, in particular methylene. Radicals R.sub.5 or R.sub.6 of
this type are therefore preferably phenylenemethylene or
methylenephenylene.
[0040] Arylenealkylenearylene R.sub.5 or R.sub.6 is preferably
phenylene(lower alkylene)phenylene having up to 4 carbon atoms in
the alkylene unit, for example phenyleneethylenephenylene.
[0041] The radicals R.sub.5 and R.sub.6 are preferably,
independently of one another, lower alkylene having 2 to 6 carbon
atoms, phenylene, unsubstituted or substituted by lower alkyl,
cyclohexylene or cyclohexylene(lower alkylene), unsubstituted or
substituted by lower alkyl, phenylene(lower alkylene), (lower
alkylene)phenylene or phenylene(lower alkylene)phenylene.
[0042] In the formula II, R.sub.7 is a primary, secondary or
tertiary amino group or a quaternary amino group of the formula
N.sup.+(R').sub.3X.sup.-, in which each R', independently of the
others, is hydrogen or a C.sub.1-C.sub.4 alkyl radical and X is a
counterion, for example HSO.sub.4.sup.-, F.sup.-, Cl.sup.-,
Br.sup.-, I.sup.-, CH.sub.3 COO.sup.-, OH.sup.-, BF.sup.-, or
H.sub.2PO.sub.4.sup.-.
[0043] The radicals R.sub.7 are, in particular, amino, mono- or
di(lower alkyl)amino, mono- or diphenylamino, (lower
alkyl)phenylamino or tertiary amino incorporated into a
heterocyclic ring, for example --NH.sub.2, --NH--CH.sub.3,
--N(CH.sub.3).sub.2, --NH(C.sub.2H.sub.5),
--N(C.sub.2H.sub.5).sub.2, --NH(phenyl), --N(C.sub.2H.sub.5)phenyl
or 2
[0044] In the formula III, R.sub.8 is the radical of a monobasic,
dibasic or tribasic, saturated or unsaturated, aliphatic or
aromatic organic acid or sulfonic acid. Preferred radicals R.sub.8
are derived, for example, from chloroacetic acid, succinic acid,
glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric
acid, itaconic acid, citraconic acid, acrylic acid, methacrylic
acid, phthalic acid and trimellitic acid.
[0045] For the purposes of this invention, the term "lower" in
connection with radicals and compounds denotes, unless defined
otherwise, radicals or compounds having up to 7 carbon atoms,
preferably having up to 4 carbon atoms.
[0046] Lower alkyl has, in particular, up to 7 carbon atoms,
preferably up to 4 carbon atoms, and is, for example, methyl,
ethyl, propyl, butyl or tert-butyl.
[0047] Lower alkoxy has, in particular, up to 7 carbon atoms,
preferably up to 4 carbon atoms, and is, for example, methoxy,
ethoxy, propoxy, butoxy or tert-butoxy.
[0048] The bivalent group --R.sub.5--NH--CO--O-- is present if q is
one and absent if q is zero. Poly(vinyl alcohol)s containing
crosslinkable groups in which q is zero are preferred.
[0049] The bivalent group
--CO--NH--(R.sub.5--NH--CO--O)q-R.sub.6--O-- is present if p is one
and absent if p is zero. Poly(vinyl alcohol)s containing
crosslinkable groups in which p is zero are preferred.
[0050] In the poly(vinyl alcohol)s comprising units containing
crosslinkable groups in which p is one, the index q is preferably
zero. Particular preference is given to poly(vinyl alcohol)s
comprising crosslinkable groups in which p is one, the index q is
zero and R.sub.5 is lower alkylene.
[0051] In the formula N.sup.+(R').sub.3X.sup.-, R' is preferably
hydrogen or C.sub.1-C.sub.3 alkyl, and X is halide, acetate or
phosphite, for example
--N.sup.+(C.sub.2H.sub.5).sub.3CH.sub.3COO--,
--N.sup.+(C.sub.2H.sub.5).sub.3Cl.sup.-, and
--N.sup.+(C.sub.2H.sub.5).su- b.3H.sub.2PO.sub.4.sup.-.
[0052] A water-soluble crosslinkable poly(vinyl alcohol) according
to the invention is more preferably a polyhydroxyl compound which
has a molecular weight of at least about 2000 and which comprises
from about 0.5 to about 80%, preferably from 1 to 50%, more
preferably from 1 to 25%, even more preferably from 2 to 15%, based
on the number of hydroxyl groups in the poly(vinyl alcohol), of
units of the formula 1, wherein R is lower alkylene having up to 6
carbon atoms, R.sub.1 is hydrogen or lower alkyl, R.sub.3 is
hydrogen, and R.sub.2 is a radical of formula (V). Where p is zero,
R.sub.4 is preferably C.sub.2-C.sub.8 alkenyl. Where p is one and q
is zero, R.sub.6 is preferably C.sub.2-C.sub.6 alkylene and R.sub.4
is preferably C.sub.2-C.sub.8 alkenyl. Where both p and q are one,
R.sub.5 is preferably C.sub.2-C.sub.6 alkylene, phenylene,
unsubstituted or lower alkyl-substituted cyclohexylene or cyclo
hexylene-lower alkylene, unsubstituted or lower alkyl-substituted
phenylene-lower alkylene, lower alkylene-phenylene, or
phenylene-lower alkylene-phenylene, R.sub.6 is preferably
C.sub.2-C.sub.6 alkylene, and R.sub.4 is preferably C.sub.2-C.sub.8
alkenyl.
[0053] A water-soluble crosslinkable poly(vinyl alcohol) according
to the invention has a molecular weight of at least about 2000.
[0054] Crosslinkable poly(vinyl alcohol)s comprising units of the
formula I, I and II, I and III, or I and II and III can be prepared
in a manner known per se. For example, U.S. Pat. Nos. 5,583,163 and
6,303,687 disclose and teach how to prepare crosslinkable polymers
comprising units of the formula I, I and II, I and II, or I and II
and III.
[0055] A water-soluble crosslinkable poly(vinyl alcohol) according
to the invention is preferably in extremely pure form, for example,
in the form of concentrated aqueous solutions that are free, or at
least substantially free, from reaction products and starting
materials (e.g., salts, non-polymeric constituents). Purification
can be carried out according to any techniques known to a person
skilled in the art, for example, by precipitation with acetone,
dialysis or ultrafiltration. A preferred purification process is
ultrafiltration, which can be carried out repeatedly, e.g., from
two to ten times, or continuously until a selected degree of purity
is achieved. A suitable measure for the degree of purity is, for
example, the sodium chloride concentration of the solution.
[0056] A modifier according to the invention is a material the
presence of which in a polymerizable material can improve at least
one physical property of an ophthalmic device made from the
polymerizable material. Examples of physical properties are stress
at break (N/mm.sup.2), percentage of elongation at break, toughness
or energy to break (N.multidot.mm), and susceptibility to
fracture.
[0057] In one embodiment, a modifier is composed of nanoparticles
having a hydrophilic surface. Exemplary nanoparticles having a
hydrophilic surface are nano-sized silica fillers.
[0058] In another embodiment, a modifier is composed of one or more
copolymers each having hydrophilic groups or units in an amount
sufficient to render it miscible with the water-soluble polyvinyl
alcohol and hydrophobic groups or units for imparting at least one
desired physical property to said ophthalmic device.
[0059] In another embodiment, a modifier is composed of a mixture
of nanbparticles having a hydrophilic surface and at least one
copolymer having hydrophilic groups or units in an amount
sufficient to render it miscible with the water-soluble polyvinyl
alcohol and hydrophobic groups or units for imparting at least one
desired physical property to the polymeric article made from the
polymerizable material.
[0060] It has been discovered here that although it is possible to
find a homopolymer of hydrophilic monomer (such as, for example,
poly(vinyl pyrrolidone) (PVP) or a dextrane) to be miscible with a
water-soluble polyvinyl alcohol, blending of such hydrophilic
homopolymer with the water-soluble polyvinyl alcohol does not allow
to make contact lenses having a significantly improved physical
property. However, it is found that by blending a copolymer, having
a balanced composition of hydrophilic and hydrophobic groups or
units, with a water-soluble polyvinyl alcohol, it is possible to
prepare a contact lens having at least one significantly improved
physical property. It is believed that hydrophilic groups or units
miscible with the water-soluble polyvinyl alcohol should be present
in an amount sufficient to ensure a desired miscibility of the
copolymer with the water-soluble polyvinyl alcohol. While the
claimed invention is not limited to the theory developed to support
this unexpected result, a proposed theory is presented herein in
order to enable the reader to better understand the invention. It
is believed that, in a polymeric article obtained by polymerizing a
water-soluble polyvinyl alcohol in the presence of a copolymer
having a balanced composition of hydrophilic and hydrophobic groups
or units, the hydrophilic groups or units the copolymer are
intertwined with the polymer meshwork of polyvinyl alcohol, whereas
the hydrophobic groups or units may form nano-composites or
microscopically co-continuous phases. Such nano-composites or
microscopically co-continuous phases may impart one or more
improved physical properties to the polymeric article.
[0061] It is understood that a copolymer, having a balanced
composition of hydrophilic and hydrophobic groups or units, as a
modifier in accordance with the present invention can optionally
contain crosslinkable groups. By having crosslinkable groups, a
copolymer can be covalently anchored to the polymeric meshwork in a
polymeric article. With such covalent attachment of a modifier,
there is no need for subsequent extraction or finishing steps to
the contact lenses produced from a composition composed of a water
soluble polyvinyl alcohol and a modifier neither concerns about the
possibility of leaching out of a modifier from contact lenses.
Therefore, contact lenses can be manufactured at considerably low
cost and it is possible to produce disposable contact lenses that
are discarded by the user after a single use.
[0062] Where a copolymer used as a modifier does not contain
crosslinkable groups, it preferably has a relatively high molecular
weight.
[0063] Any known suitable copolymer having a balanced composition
of hydrophilic and hydrophobic groups or units can be used in the
present invention. A person skilled in the art will know well how
to select a copolymer as a modifier and how to make a copolymer
according to any known suitable method.
[0064] One example of a copolymer as a modifier is a
non-crosslinkable polyurethane or a crosslinkable polyurethane. For
example, a modifier according to the present invention is a vinyl
group-terminated polyurethane, which is prepared by reacting an
isocyanate-capped polyurethane with an ethylenically unsaturated
amine (primary or secondary amine) or an ethylenically unsaturated
monohydroxy compound.
[0065] An isocyanate-capped polyurethane according to the invention
is a copolymerization product of
[0066] (a) at least one polyalkylene glycol of formula
HO--(R.sub.9--O).sub.n--(R.sub.10--O).sub.m--(R.sub.11--O).sub.l--H
(1)
[0067] wherein R.sub.9, R.sub.10, and R.sub.11, independently of
one other, are each linear or branched C.sub.2-C.sub.4-alkylene,
and n, m and l, independently of one another, are each a number
from 0 to 100, wherein the sum of (n+m+l) is 5 to 100,
[0068] (b) at least one branching agent selected from the group
consisting of
[0069] (i) a linear or branched aliphatic polyhydroxy compound of
formula
R.sub.12--(OH).sub.x (2),
[0070] wherein R.sub.12 is a linear or branched C.sub.3-C.sub.18
aliphatic multi-valent radical and x is a number .gtoreq.3,
[0071] (ii) a polyether polyol, which is the polymerization product
of a compound of formula (2) and a glycol,
[0072] (iii) a polyester polyol, which is the polymerization
product of a compound of formula (2), a dicarboxylic acid or a
derivative thereof and a diol, and
[0073] (iv) a cycloaliphatic polyol selected from the group
consisting of a C.sub.5-C.sub.8-cycloalkane which is substituted by
.gtoreq.3 hydroxy groups and which is unsubstituted by alkyl
radical, a C.sub.5-C.sub.8-cycloalkane which is substituted by
.gtoreq.3 hydroxy groups and which is substituted by one or more
C.sub.1-C.sub.4 alkyl radicals, and an unsubstituted mono- and
disaccharide,
[0074] (v) an aralkyl polyol having at least three hydroxy
C.sub.1-C.sub.4 alkyl radicals, and
[0075] (c) at least one di- or polyisocyanate of formula
R.sub.13--(NCO).sub.y (3)
[0076] wherein R.sub.13 a linear or branched C.sub.3-C.sub.24
aliphatic polyisocyanate, the radical of a C.sub.3-C.sub.24
cycloaliphatic or aliphatic-cycloaliphatic polyisocyanate, or the
radical of a C.sub.3-C.sub.24 aromatic or araliphatic
polyisocyanate, and y is a number from 2 to 6.
[0077] In formula (1), n, m and l, independently of one another,
preferably each denote a number from 0 to 50, whereby the sum of
(n+m+l) is 8 to 50. Most preferably, n, m and l, independently of
one another, each denote a number from 0 to 25, whereby the sum of
(n+m+l) is 9 to 25.
[0078] In formula (1), where l is zero, n and m, independently of
one another, are each a number from 0 to 100, preferably 0 to 50,
and most preferably 0 to 25, and the sum of (n+m) is 5 to 100,
preferably 8 to 50, most preferably 9 to 25.
[0079] In formula (1), where l and m are each 0, n is a number from
5 to 100, preferably 8 to 50, most preferably 9 to 25.
[0080] Exemplary poly(alkylene glycol)s include, but are not
limited to a poly(ethylene glycol), a poly(propylene glycol), a
poly(ethylene glycol)/poly(propylene glycol) block-polymer, a
poly(ethylene glycol)/poly(propylene glycol)/poly(butylene glycol)
block polymer, a polytetrahydrofuran, a poloxamer, and mixtures
thereof.
[0081] Poloxamers are hydroxy terminated tri-block copolymers with
the structure PEG-PPG-PEG (where "PEG" is poly(ethylene glycol) and
"PPG" is poly(propylene glycol)) and are available, for example,
under the tradename PLURONIC.RTM.. The order of PEG and PPG blocks
can be reversed creating block copolymers with the structure
PPG-PEG-PPG, which are available, for example, under the tradename
PLURONIC-R.RTM.). A considerable number of poloxamers is known,
differing merely in the molecular weight and in the PEG/PPG ratio.
Examples are poloxamer 101, 105, 108, 122, 123, 124, 181, 182, 183,
184, 185, 188, 212, 215, 217, 231, 234, 235, 237, 238, 282, 284,
288, 331, 333, 334, 335, 338, 401, 402, 403 and 407. Poloxamer 101
has a PEG/PPG weight ratio of about 10/90 and poloxamer 108 having
a PEG/PPG weight ratio of about 80/20.
[0082] Polyoxypropylene-polyoxyethylene block copolymers can also
be designed with hydrophilic blocks comprising a random mix of
ethylene oxide and propylene oxide repeating units. To maintain the
hydrophilic character of the block, ethylene oxide will
predominate. Similarly, the hydrophobic block can be a mixture of
ethylene oxide and propylene oxide repeating units. Such block
copolymers are available under the tradename PLURADOT.RTM..
[0083] The weight average molecular weight of poloxamers may vary
within wide limits. An average molecular weight of, may be, for
example, from about 1000 to 20000, preferably from 1000 to 15000,
more preferably from 1000 to 8000 and in particular from 1000 to
5000.
[0084] A branching agent of formula (2) is preferably a linear or
branched C.sub.3 to C.sub.12 aliphatic polyol, more preferably a
linear or branched C.sub.3 to C.sub.8 aliphatic polyol. The
variable x in formula (2) is preferably a number from 3 to 12, more
preferably a number from 3 to 8, even more preferably a number from
3 to 6, and most preferably the number 3.
[0085] Examples of a branching agent of formula (2) are glycerol,
diglycerol, triglycerol, 1,1,1-trishydroxymethylethane,
1,1,1-trishydroxymethylpropane, 1,2,4-butanetriol,
1,2,6-hexanetriol, erythritol, pentaerythritol, di- or
tripentaerythritol, arabitol, sorbitol, disorbitol or mannitol and
mixtures thereof. Preferred compounds of formula (2) are glycerol,
1,1,1-tris-hydroxymethylpropane, 1,2,4-butanetriol, erythritol,
pentaerythritol, arabitol or sorbitol. A group of preferred
branching agents of formula (2) comprises glycerol,
1,1,1-tris-hydroxymethylpropane, pentaerythritol, and
pentaerythritol ethoxylate.
[0086] Further suitable as a branching agent according to (b) are
reaction products of the above-mentioned polyhydroxy compounds of
formula (2) with a dicarboxylic acid, a dicarboxylic acid
anhydride, a dicarboxylic acid ester, a dicarboxylic acid halide,
or a diol.
[0087] Where at least one branching agent according to (b) is a
polyester polyol, the branching agent is preferably an oligomeric
reaction product of a compound of formula (2), wherein the
above-mentioned meanings and preferences apply, with an aliphatic
or cycloaliphatic dicarboxylic acid having 3 to 12 carbon atoms, or
an aromatic dicarboxylic acid having 5 to 15 carbon atoms, or an
appropriate derivative thereof, e.g. a corresponding dicarboxylic
acid anhydride, ester or halide, as well as a diol as chain
extender. Examples of suitable dicarboxylic acids are malonic acid,
succinic acid, 2,2-dimethylsuccinic acid, glutaric acid, adipic
acid, pimelic acid, sebacic acid, tetrahydrophthalic acid,
hexahydrophthalic acid, phthalic acid, isophthalic acid,
terephthalic acid, maleic acid or fumaric acid, as well as the
corresponding dicarboxylic acid esters, halides or anhydrides.
Appropriate diols are e.g. linear or branched
C.sub.2-C.sub.20-alkyl-diols.
[0088] Where at least one branching agent according to (b) is a
cycloaliphatic polyol, the branching agent may be e.g. cyclopentane
or preferably a cyclohexane, which is respectively substituted by 3
to 5 and preferably by 3 or 4 hydroxy groups and bears no further
substituents or hetero atoms. Further suitable cycloaliphatic
polyols according to (b) are represented by unsubstituted mono- or
disaccharides, e.g. glucose, fructose, mannose, galactose, maltose,
lactose or saccharose.
[0089] In formula (3), y is preferably a number from 2 to 4, more
preferably 2.
[0090] Where y is 2 in the formula (3), R.sub.13 is the radical of
a linear or branched C.sub.3-C.sub.18-alkylene, an unsubstituted or
C.sub.1-C.sub.4-alkyl-substituted or
C.sub.1-C.sub.4-alkoxy-substituted C.sub.6-C.sub.10-arylene, a
C.sub.7-C.sub.19-aralkylene, a
C.sub.6-C.sub.11-arylene-C.sub.1-C.sub.2-alkylene-C.sub.6-C.sub.10-arylen-
e, a C.sub.3-C.sub.8-cycloalkylene, a
C.sub.3-C.sub.8-cycloalkylene-C.sub.- 1-C.sub.6-alkylene, a
C.sub.3-C.sub.8-cycloalkylene-C.sub.1-C.sub.2-alkyle-
ne-C.sub.3-C.sub.8-cycloalkylene, or a
C.sub.1-C.sub.6-alkylene-C.sub.3-C.-
sub.8-cycloalkylene-C.sub.1-C.sub.6-alkylene.
[0091] Where R.sub.13 is the radical of an alkylene, R.sub.13 is
preferably a linear or branched C.sub.4-C.sub.12-alkylene radical,
more preferably a linear or branched C.sub.6-C.sub.10-alkylene
radical. Examples of preferred alkylene radicals are 1,4-butylene,
2,2-dimethyl-1,4-butylene, 1,5-pentylene,
2,2-dimethyl-1,5-pentylene, 1,6-hexylene, 2,2,3- or
2,2,4-trimethyl-1,5-pentylene, 2,2-dimethyl-1,6-hexylene, 2,2,3- or
2,2,4- or 2,2,5-trimethyl-1,6-hexyle- ne,
2,2-dimethyl-1,7-heptylene, 2,2,3- or 2,2,4- or 2,2,5- or
2,2,6-trimethyl-1,7-heptylene, 1,8-octylene,
2,2-dimethyl-1,8-octylene or 2,2,3- or 2,2,4- or 2,2,5- or 2,2,6-
or 2,2,7-trimethyl-1,8-octylene.
[0092] Where R.sub.13 is the radical of an arylene, the arylene is
preferably naphthylene, more preferably phenylene. If the arylene
is substituted, a substituent is preferably located in ortho
position to an isocyanate group. Examples of substituted arylene
are 1-methyl-2,4-phenylene, 1,5-dimethyl-2,4-diphenylene,
1-methoxy-2,4-phenylene or 1-methyl-2,7-naphthylene.
[0093] Where R.sub.13 is the radical of an aralkylene, the
aralkylene is preferably naphthylalkylene, more preferably
phenylalkylene. The alkylene group in aralkylene preferably
contains 1 to 12, more preferably 1 to 6, even more preferably 1 to
4, most preferably 1 to 2 C-atoms. A few examples are 1,3- or
1,4-benzylene, naphth-2-yl-7-methylene, 6-methyl-1,3- or
-1,4-benzylene, 6-methoxy-1,3- or -1,4-benzylene.
[0094] Where R.sub.13 is the radical of a cycloalkylene, the
cycloalkylene is preferably C.sub.5-C.sub.6-cycloalkylene, more
preferably cyclohexylene which is respectively unsubstituted or
methyl-substituted. A few examples are 1,3-cyclobutylene,
1,3-cyclopentylene, 1,3- or 1,4-cyclohexylene, 1,3- or
1,4-cycloheptylene, 1,3- or 1,4- or 1,5-cyclooctylene,
4-methyl-1,3-cyclopentylene, 4-methyl-1,3-cyclohexylen- e,
4,4-dimethyl-1,3-cyclohexylene, 3-methyl- or
3,3-dimethyl-1,4-cyclohexy- lene, 3,5-dimethyl-1,3-cyclohexylene,
2,4-dimethyl-1,4-cyclohexylene.
[0095] Where R.sub.13 is the radical of a cycloalkylene-alkylene,
the cycloalkylene-alkylene is preferably
cyclopentylene-C.sub.1-C.sub.4-alkyl- ene, more preferably
cyclohexylene-C.sub.1-C.sub.4-alkylene which is respectively
unsubstituted or substituted once or several times by
C.sub.1-C.sub.4-alkyl, especially methyl. The group
cycloalkylene-alkylene preferably denotes cyclohexylene-ethylene
and most preferably denotes cyclohexylene-methylene, which is
respectively unsubstituted in the cyclohexylene radical or
substituted by 1 to 3 methyl groups. A few examples are
cyclopent-1-yl-3-methylene, 3-methyl-cyclopent-1-yl-3-methylene,
3,4-dimethyl-cyclopent-1-yl-3-methyl- ene,
3,4,4-trimethyl-cyclopent-1-yl-3-methylene, cyclohex-1-yl-3- or
-4-methylene, 3- or 4- or 5-methyl-cyclohex-1-yl-3- or
-4-methylene, 3,4- or 3,5-dimethyl-cyclohex-1-yl-3- or
-4-methylene, 3,4,5- or 3,4,4- or 3,5,5-trimethyl-cyclohex-1-yl-3-
or -4-methylene.
[0096] Where R.sub.13 is the radical of an
alkylene-cycloalkylene-alkylene- , the
alkylene-cycloalkylene-alkylene is preferably
C.sub.1-C.sub.4-alkylene-cyclopentylene-C.sub.1-C.sub.4-alkylene
and especially
C.sub.1-C.sub.4-alkylene-cyclohexylene-C.sub.1-C.sub.4-alkylen- e,
which is respectively unsubstituted or substituted once or several
times by C.sub.1-C.sub.4-alkyl, most preferably methyl. The group
alkylene-cycloalkylene-alkylene preferably denotes
ethylene-cyclohexylene-ethylene and most preferably
methylene-cyclohexylene-methylene, which is respectively
unsubstituted in the cyclohexylene radical or substituted by 1 to 3
methyl groups. A few examples are cyclopentane-1,3-dimethylene,
3-methyl-cyclopentane-1,3-dime- thylene
3,4-dimethyl-cyclopentane-1,3-dimethylene, 3,4,4-trimethyl-cyclope-
ntane-1,3-dimethylene, cyclohexane-1,3- or -1,4-dimethylene, 3- or
4- or 5-methyl-cyclohexane-1,3- or -1,4-dimethylene, 3,4- or
3,5-dimethyl-cyclohexane-1,3- or -1,4-dimethylene, 3,4,5- or 3,4,4-
or 3,5,5-trimethyl-cyclohexane-1,3- or -1,4-dimethylene.
[0097] Where R.sub.13 is the radical of a
cycloalkylene-alkylene-cycloalky- lene, the
cycloalkylene-alkylene-cycloalkylene is preferably
C.sub.5-C.sub.6-cycloalkylene-methylene-C.sub.5-C.sub.6-cycloalkylene,
which may respectively be unsubstituted in the cycloalkyl ring by
one or more methyl groups.
[0098] Where R.sub.13 is the radical of an
arylene-alkylene-arylene, the arylene-alkylene-arylene is
preferably phenylene-methylene-phenylene, which may respectively be
unsubstituted in the phenyl ring by one or more methyl groups.
[0099] Examples of especially preferred diisocyanates of formula
(3) are isophorone diisocyanate (IPDI),
methylenebis(cyclohexyl-isocyanate),
1,6-diisocyanato-2,2,4-trimethyl-n-hexane (TMDI),
methylenebis(phenyl-iso- cyanate) or hexamethylene-diisocyanate
(HMDI).
[0100] Examples of ethylenically unsaturated monohydroxy compound
includes, without limitation, hydroxy-substituted lower
alkylacrylates and -methacrylates, hydroxy-substituted lower
alkyl-acrylamides and -methacrylamides, hydroxy-substituted lower
alkylvinyl-ethers. Examples of hydroxy-substituted lower
alkylacrylates and -methacrylates are 2-hydroxyethyl acrylate and
2-hydroxyethyl methacrylate.
[0101] An ethylenically unsaturated amine has formula (4), (4') or
(4") 3
[0102] In which, i, j and k, independent of one another, are o or
1;
[0103] R.sub.14 is hydrogen, a linear or branched C.sub.1-C.sub.24
alkyl, a C.sub.2-C.sub.24 alkoxyalkyl, a C.sub.2-C.sub.24
alkylcarbonyl, a C.sub.2-C.sub.24 alkoxycarbonyl, an unsubstituted
or C.sub.1-C.sub.4 alkyl- or C.sub.1-C.sub.4 alkoxy-substituted
C.sub.6-C.sub.10 aryl, a C.sub.7-C.sub.18 aralkyl, a
C.sub.13-C.sub.22 arylalkylaryl, a C.sub.3-C.sub.8 cycloalkyl, a
C.sub.4-C.sub.14 cycloalkylalkyl, a C.sub.7-C.sub.18
cycloalkylalkylcycloalkyl, a C.sub.5-C.sub.20 alkylcycloalkylalkyl,
or an aliphatic-heterocyclic radical;
[0104] Z is a C.sub.1-C.sub.1-2 alkylene radical, phenylene radical
or C.sub.7-C.sub.12 aralkylene radical;
[0105] R.sub.15 and R.sub.15', independently of each other, are
hydrogen, C.sub.1-C.sub.4 alkyl or halogen; and
[0106] Q is an ethylenically unsaturated copolymerizable radical
having from 2 to 24 carbon atoms which may be further
substituted.
[0107] Aryl R.sub.14 is a carbocyclic aromatic radical, which is
unsubstituted or substituted by preferably lower alkyl
(C.sub.1-C.sub.4) or lower alkoxy (C.sub.1-C.sub.4). Examples are
phenyl, toluyl, xylyl, methoxyphenyl, t-butoxyphenyl, naphthyl or
phenanthryl.
[0108] Cycloalkyl R.sub.14 is preferably C.sub.5-C.sub.6 cycloalkyl
and most preferably cyclohexyl that is unsubstituted or substituted
by methyl. Some examples are cyclobutyl, cyclopentyl, cyclohexyl,
cycloheptyl, cyclooctyl, 4-methyl-cyclopentyl, 4-methyl-cyclohexyl,
4,4-dimethyl-cyclohexyl, 3-methyl- or 3,3-dimethyl-cyclohexyl,
3,5-dimethyl-cyclohexyl and 2,4-dimethyl-cyclohexyl.
[0109] When R.sub.14 is cycloalkylalkyl, it is preferably
cyclopentyl-C.sub.1-C.sub.4 alkyl and especially
cyclohexyl-C.sub.1-C.sub- .4 alkyl, each unsubstituted or mono- or
poly-substituted by C.sub.1-C.sub.4 alkyl, especially methyl. More
preferably, the group cycloalkyl-alkyl is cyclohexylethyl and, most
preferably, cyclohexylmethyl, each unsubstituted or substituted in
the cyclohexyl radical by from 1 to 3 methyl groups.
[0110] When R.sub.14 is alkylcycloalkylalkyl, it is preferably
C.sub.1-C.sub.4 alkyl-cyclopentyl-C.sub.1-C.sub.4 alkyl and
especially C.sub.1-C.sub.4 alkyl-cyclohexyl-C.sub.1-C.sub.4 alkyl,
each unsubstituted or mono- or poly-substituted by C.sub.1-C.sub.4
alkyl, especially methyl. More preferably, the group
alkylcycloalkylalkyl is ethylcyclohexylethyl and, most preferably,
is methylcyclohexylmethyl, each unsubstituted or substituted in the
cyclohexyl radical by from 1 to 3 methyl groups.
[0111] When R.sub.14 is cycloalkylalkylcycloalkyl or arylalkylaryl,
it is preferably C.sub.5-C.sub.6 cycloalkyl-methyl-C.sub.5-C.sub.6
cycloalkyl or phenylmethylphenyl, each of which may be
unsubstituted or substituted in the cycloalkyl or phenyl ring by
one or more methyl groups.
[0112] Suitable substituents on the ethylenically unsaturated
C.sub.2-C.sub.24 radical Q are, for example, C.sub.1-C.sub.4
alkoxy, halogen, phenyl or carboxy.
[0113] Q is, for example, a radical of formula 4
[0114] wherein r is the number 0 or 1,
[0115] each of R.sub.16 and R.sub.17 independently of the other is
hydrogen, C.sub.1-C.sub.4 alkyl, phenyl, carboxy or halogen,
[0116] R.sub.18 is hydrogen, C.sub.1-C.sub.4 alkyl or halogen,
and
[0117] Z' is linear or branched C.sub.1-C.sub.1-2 alkylene or
unsubstituted or C.sub.1-C.sub.4 alkyl- or C.sub.1-C.sub.4
alkoxy-substituted phenylene or C.sub.7-C.sub.12 aralkylene.
[0118] When Z' is a phenylene radical, it is, for example,
unsubstituted or methyl- or methoxy-substituted 1,2-, 1,3- or
1,4-phenylene. Preferably, Z' as a phenylene radical is 1,3- or
1,4-phenylene.
[0119] When Z' is an aralkylene radical, it is, for example,
unsubstituted or methyl- or methoxy-substituted benzylene, wherein
the methylene group is bonded to the amine nitrogen in each case.
Preferably, Z' as an aralkylene radical is the 1,3- or
1,4-phenylenemethylene radical, wherein the methylene group is
bonded to the amine nitrogen --NH-- in each case.
[0120] Z' is preferably unsubstituted or methyl- or
methoxy-substituted phenylene or phenylenemethylene or
C.sub.1-C.sub.1-2alkylene, more preferably 1,3- or 1,4-phenylene or
C.sub.1-C.sub.6alkylene, especially C.sub.1-C.sub.2alkylene and
most preferably methylene.
[0121] r is the number 1 or, preferably, the number 0.
[0122] R.sub.18 is preferably hydrogen, methyl or chlorine and most
preferably hydrogen or methyl.
[0123] Each of R.sub.16 and R.sub.17, independently of the other,
is preferably hydrogen, carboxy, chlorine, methyl or phenyl. In a
preferred embodiment of the invention, R.sub.16 is hydrogen,
chlorine, methyl or phenyl and R.sub.17 is hydrogen or carboxy.
Most preferably, R.sub.16 and R.sub.17 are each hydrogen.
[0124] Especially preferred radicals Q correspond to formula (5)
wherein r is 0, R.sub.18 is hydrogen or methyl, R.sub.16 is
hydrogen, methyl, chlorine or phenyl and R.sub.17 is hydrogen or
carboxy.
[0125] Other especially preferred radicals Q correspond to the
above formula (5) wherein r is 1, Z' is 1,3- or 1,4-phenylene or
C.sub.1-C.sub.6 alkylene, especially C.sub.1-C.sub.2 alkylene,
R.sub.18 is hydrogen or methyl and R.sub.16 and R.sub.17 are each
hydrogen.
[0126] Examples of suitable radicals Q are vinyl, 2-propenyl,
allyl, 2-butenyl, o-, m- or p-vinylphenyl, vinylphenyl,
vinylnaphthyl, allylphenyl, styryl, 2-carboxyvinyl,
2-chloro-2-carboxyvinyl, 1,2-dichloro-2-carboxyvinyl,
1,2-dimethyl-2-carboxyvinyl and 2-methyl-2-carboxyvinyl.
[0127] Examples of suitable ethylenically unsaturated amine are
2-(ter-butylamino)ethylmethacrylate (TBAM), and vinyl aniline.
[0128] The isocyanate-capped polyurethane polymers according to the
invention may be produced by following a solventless process.
[0129] For example, in a solventless process, first one or more
polyalkylene glycols of formula (1) (component (a)) is mixed with
one or more branching agents (component (b)) and the mixture is
heated to and maintained at a melting temperature or above. Then,
at least one di- or polyisocyanate of formula (3) (component (c))
is added to the melted mixture to make a melted reaction mixture
comprising component (a), component (b) and component (c) in a
desired stoichiometry. The temperature of the melted reaction
mixture is continuously and thoroughly stirred at the melting
temperature or above and preferably under an inert atmosperic
environment (for example, in nitrogen or argon atmosphere).
Reaction is monitored by, for example, monitoring the isocyanate
peak in FT-IR spectroscopy.
[0130] Components (a)-(c) are all known compounds or compound
mixtures, or may be obtained in accordance with methods known per
se.
[0131] It should be understood that components (a), (b), and (c)
can be mixed together in a desired stoichiometry and the mixture
then can be melted and maintained at a melting temperature or above
to start reaction.
[0132] The stoichiometry of components (a), (b) and (c) in the
melted reaction mixture is advantageously chosen so that the number
of NCO equivalents of component (c) is greater than the sum of OH
equivalents of components (a) and (b). Preferably, the
stoichiometry of components (a), (b) and (c) in the melted reaction
mixture is chosen so that the molar ratio of component (a) to
component (b) to component (c) is about 4:1:7.
[0133] It should be further understood that the isocayanate-capped
polyurethane polymers according to the invention may be produced by
reacting components (a), (b), and (c) and optionally additional
copolymerizable monomers in an inert solvent at a temperature of
e.g. 30.degree. C. to 150.degree. C.
[0134] Suitable inert solvents are aprotic, preferably polar
solvents, for example hydrocarbon halides (chloroform, methylene
chloride, trichloroethane, tetrachloroethane, chlorobenzene),
ethers (tetrahydrofuran, dioxane), ketones (acetone, ethyl methyl
ketone, dibutyl ketone, methyl isobutyl ketone), carboxylic acid
esters and lactones (ethyl acetate, butyrolactone, valerolactone),
alkylated carboxylic acid amides (N,N-dimethylacetamide,
N-methylpyrrolidone), nitriles (acetonitrile), sulphones and
sulphoxides (dimethyl sulphoxide, tetramethylene sulphone). Polar
solvents are preferably employed.
[0135] Furthermore, it is preferable for the reaction of the
hydroxy-group-containing components (a) and (b) with the
isocyanate-group-containing components (c) to be carried out in the
presence of a catalyst, since the reaction time can be shortened.
Suitable catalysts are for example metal salts such as alkali metal
salts or tin salts of organic carboxylic acids, or tertiary amines,
for example, (C.sub.1-C.sub.6-alkyl).sub.3N (triethylamine,
tri-n-butylamine), N-methylpyrrolidine, N-methylmorpholine,
N,N-dimethylpiperidine, pyridine or 1,4-diaza-bicyclooctane. Tin
salts have proved to be particularly effective, especially
alkyl-tin salts of carboxylic acids, for example dibutyl tin
dilaurate (DBTDL) and tin dioctoate.
[0136] The catalyst is employed in the reaction e.g. in a molar
ratio of 1:10 to 1:1000, preferably 1:50 to 1:750, most preferably
ca. 1:100 to 1:500, respectively based on component (a).
[0137] The reaction times may vary within a broad range, whereby
progress of the reaction can be followed well by monitoring the
reduction of the isocyanate content in the reaction mixture.
[0138] It is particularly preferred that the isocyanate-capped
polyurethane polymers are produced in a solventless process. By
using a solventless process, the production cost associated with
solvent and its disposal can be eliminated.
[0139] Once the reaction of components (a) and (b) with component
(c) is completed, the obtained isocyanate-capping polyurethane can
be reacted directly with an ethylenically unsaturated amine
(primary or secondary amine) and an ethylenically unsaturated
monohydroxy compound, to prepare a vinyl group terminated
polyurethane. Optionally, the obtained isocyanate-capping
polyurethane can be purified prior to the reaction.
[0140] Isolation and purification of the vinyl group-terminated
polyurethane are effected by known processes, for example
extraction, crystallization, re-crystallization, ultrafiltration or
by chromatographic purification methods. The compounds are obtained
in high yields and with high purity.
[0141] The vinyl group-terminated polyurethanes according to the
invention are radiation-curable, but uncrosslinked or at least
substantially uncrosslinked; nevertheless, they are stable, i.e.
spontaneous crosslinking due to homopolymerization does not take
place substantially. The term "radiation-curable" in reference to a
prepolymer means that the prepolymer can be crosslinked or
polymerized by actinic radiation, including, for example, UV
radiation, ionizing radiation such gamma radiation or X-rays,
microwave, and the like.
[0142] The average molecular weight of the vinyl group-terminated
polyurethanes according to the invention may vary within a broad
range. An average molecular weight of e.g. 1000 to 50,000 has
proved to be advantageous for the vinyl group-terminated
polyurethanes according to the invention.
[0143] The above described isocyanate-capping polyurethane can also
be used to prepared other non-crosslinkable polyurethanes, for
example, by reacting with water, amine, or the like.
[0144] Another example of a copolymer as a modifier in accordance
with the present invention can be a copolymerization product of at
least one hydrophilic monomer and at least one hydrophobic
monomers, wherein the homopolymer of said at least one hydrophilic
monomer is miscible with the water-soluble polyvinyl alcohol having
crosslinkable groups. Exemplary preferred hydrophilic monomers
include, but are not limited to, hydroxy-substituted
alkyl(meth)acrylates, N-vinyl-lactams, N,N-dialkyl-methacrylamides
and vinylically unsaturated carboxylic acids with a total of 3 to 5
carbon atoms.
[0145] A N-vinyl lactam in accordance with the invention has a
structure of formula (VI) 5
[0146] wherein
[0147] R.sub.19 is an alkylene di-radical having from 2 to 8 carbon
atoms,
[0148] R.sub.20 is hydrogen, alkyl, aryl, aralkyl or alkaryl,
preferably hydrogen or lower alkyl having up to 7 and, more
preferably, up to 4 carbon atoms, such as, for example, methyl,
ethyl or propyl; aryl having up to 10 carbon atoms, and also
aralkyl or alkaryl having up to 14 carbon atoms; and
[0149] R.sub.21 is hydrogen or lower alkyl having up to 7 and, more
preferably, up to 4 carbon atoms, such as, for example, methyl,
ethyl or propyl.
[0150] Examples of N-vinyl lactams corresponding to the above
structural formula (VI) are N-vinyl-2-pyrrolidone,
N-vinyl-2-piperidone, N-vinyl-2-caprolactam,
N-vinyl-3-methyl-2-pyrrolidone, N-vinyl-3-methyl-2-piperidone,
N-vinyl-3-methyl-2-caprolactam, N-vinyl-4-methyl-2-pyrrolidone,
N-vinyl-4-methyl-2-caprolactam, N-vinyl-5-methyl-2-pyrrolidone,
N-vinyl-5-methyl-2-piperidone, N-vinyl-5,5-dimethyl-2-pyrrolidone,
N-vinyl-3,3,5-trimethyl-2-pyrrolidone- ,
N-vinyl-5-methyl-5-ethyl-2-pyrrolidone,
N-vinyl-3,4,5-trimethyl-3-ethyl-- 2-pyrrolidone,
N-vinyl-6-methyl-2-piperidone, N-vinyl-6-ethyl-2-piperidone- ,
N-vinyl-3,5-dimethyl-2-piperidone,
N-vinyl-4,4-dimethyl-2-piperidone, N-vinyl-7-methyl-2-caprolactam,
N-vinyl-7-ethyl-2-caprolactam, N-vinyl-3,5-dimethyl-2-caprolactam,
N-vinyl-4,6-dimethyl-2-caprolactam and
N-vinyl-3,5,7-trimethyl-2-caprolactam.
[0151] A N-vinyl lactam according to the invention is preferably a
heterocyclic monomer of formula (VI) containing preferably from 4
to 6 carbon atoms, more preferably 4 carbon atoms in the
heterocyclic ring, wherein R.sub.20 and R.sub.21 are each
independently of the other hydrogen or lower alkyl.
[0152] A N-vinyl lactam copolymer can be prepared by
copolymerization of at least one N-vinyl lactam of formula (VI)
with one or more hydrophobic monomer according to any method known
to a person skilled in the art.
[0153] Where the hydrophilic monomer is a
N,N-dialkyl-methacrylamide, alkyl is preferably methyl, ethyl,
propyl, or butyl. N,N-dimethylacryamide is a more preferred
embodiment of the hydrophilic monomer.
[0154] Where the hydrophilic monomer is a hydroxy-substituted
alkyl(meth)acrylate, alkyl is preferably methyl, ethyl, propyl, or
butyl.
[0155] Suitable hydrophobic monomers include, without limitation,
C.sub.1-C.sub.18-alkylacrylates and -methacrylates,
C.sub.3-C.sub.18 alkylacrylamides and -methacrylamides,
acrylonitrile, methacrylonitrile,
vinyl-C.sub.1-C.sub.18-alkanoates, C.sub.2-C.sub.18-alkenes,
C.sub.2-C.sub.18-halo-alkenes, di-C.sub.1-C.sub.7
alkylamino-C.sub.1-C.su- b.7 alkylacrylate, styrene,
C.sub.1-C.sub.6-alkylstyrene, vinylalkylethers in which the alkyl
moiety has 1 to 6 carbon atoms,
C.sub.2-C.sub.10-perfluoralkyl-acrylates and -methacrylates or
correspondingly partially fluorinated acrylates and methacrylates,
C.sub.3-C.sub.12-perfluoralkyl-ethyl-thiocarbonylaminoethyl-acrylates
and -methacrylates, acryloxy and methacryloxy-alkylsiloxanes,
N-vinylcarbazole, C.sub.1-C.sub.12-alkylesters of maleic acid,
fumaric acid, itaconic acid, mesaconic acid and the like.
Preference is given e.g. to C.sub.1-C.sub.4-alkylesters of
vinylically unsaturated carboxylic acids with 3 to 5 carbon atoms
or vinylesters of carboxylic acids with up to 5 carbon atoms.
[0156] In another aspect, the present invention relates to a
polymeric article which is a product of crosslinking of a
polymerizable material of the invention (described-above) in the
presence or preferably in the absence of one or more additional
vinylic comonomers. The polymerizable material of the invention may
be crosslinked in an extremely effective and well-directed manner
upon actinic irradiation, in particular by UV irradiation.
Crosslinking may take place in the presence or preferably in the
absence of an additional vinylic comonomer. The resulting
crosslinked polymers are insoluble in water, and preferably are
substantially free of extractable chemicals.
[0157] A polymeric article according to the invention is an
ophthalmic device, preferably a soft contact lens, more preferably
a hydrogel contact lens.
[0158] In the case of photo-crosslinking, a photo-initiator is
suitably added which can initiate radical crosslinking. Examples of
these are familiar to the person skilled in the art, and suitable
photo-initiators which may be mentioned in particular are
benzoin-methylether, 1-hydroxy-cyclo-hexyl-phenylketone,
Darocure.RTM. 1173 or Irgacure.RTM. types. Crosslinking may be
commenced by actinic radiation, e.g. UV light, or by ionized
radiation, e.g. gamma rays or X-rays.
[0159] Photo-crosslinking is preferably effected directly from an
aqueous solution of a polymerizable material of the invention,
which may be obtained as the result of the preferred purification
step, ultrafiltration. For example, photo-crosslinking may be
undertaken from a 15 to 90% aqueous solution.
[0160] The process for the production of polymeric articles
according to the invention comprises radiation-crosslinking an
aqueous solution of a polymerizable material of the invention, the
aqueous solution comprising preferably a photoinitiator and
optionally a vinylic monomer.
[0161] The vinylic monomer which may be additionally used for
photo-crosslinking in accordance with the invention may be
hydrophilic, hydrophobic or may be a mixture of a hydrophobic and a
hydrophilic vinylic monomers. Suitable vinylic monomers include
especially those normally used for the manufacture of contact
lenses. A "hydrophilic vinylic monomer" refers to a monomer which
as a homopolymer typically yields a polymer that is water-soluble
or can absorb at least 10 percent by weight water.
[0162] The process according to the invention for molding a
polymerizable material into ophthalmic devices, especially contact
lenses, may take place in a manner known to a person skilled in the
art, for example, photo-crosslinking of the polymerizable material
in an appropriate contact lens mold. Further examples of molded
articles according to the invention, apart from contact lenses, are
e.g. intra-ocular lenses or eye dressings, furthermore biomedical
articles which may be used in surgery, such as heart valves,
artificial arteries or the like, also films or membranes, e.g.
membranes for diffusion control, photo-structurable films for data
storage, or photo resist materials, e.g. membranes or molded
articles for etch resist printing or screen resist printing.
[0163] In another further aspect, the present invention provides a
method for producing an ophthalmic device, the method comprising
the steps of: a) introducing an aqueous solution of an
above-described polymerizable material of the invention, in the
presence or preferably in the absence of one or more additional
vinylic comonomers, and optionally in the presence of a
photo-initiator, into a mold; b) crosslinking by actinic radiation
the polymerizable material, and c) opening the mold so that the
ophthalmic device can be removed from the mold.
[0164] The polymerizable material solution may be introduced into a
mold according to any suitable method known to a person skilled in
the art, especially conventional dispensing, e.g. dropwise
addition. If vinylic monomers are present, the vinylic monomers are
advantageously mixed first with the polymerizable material and then
introduced into the mold.
[0165] Appropriate disposable molds are made, for example, from
polypropylene. Suitable materials for re-usable moulds are e.g.
quartz, sapphire glass or metals.
[0166] If the molded articles to be produced are contact lenses,
these may be produced in a manner known to a person skilled in the
art, e.g. in a conventional "spin-casting mold", as described for
example in U.S. Pat. No. 3,408,429, or by the so-called full mold
process in a static form, as described e.g. in U.S. Pat. Nos.
4,347,198, 5,508,317, 5,583,463, 5,789,464, and 5,849,810.
[0167] Crosslinking may be initiated in the mold e.g. by means of
actinic radiation, such as UV irradiation, ionizing radiation
(e.g., gamma or X-ray irradiation).
[0168] As already mentioned, photo-crosslinking is advantageously
carried out in the presence of a photo-initiator which can initiate
radical crosslinking. The photo-initiator is advantageously added
to the prepolymers according to the invention prior to introducing
them into the mold, preferably by mixing the polymers and the
photo-initiator together. The amount of photo-initiator may be
selected from a wide range, whereby an amount of up to 0.05 g/g
polymer and especially up to 0.003 g/g polymer has proved
favorable.
[0169] What is notable is that the crosslinking according to the
invention may be effected in a very short time, e.g. in .ltoreq.60
minutes, advantageously in .ltoreq.20 minutes, preferably in
.ltoreq.10 minutes, most preferably in .ltoreq.5 minutes,
particularly preferably in 1 to 60 seconds and most particularly in
1 to 30 seconds.
[0170] What is also notable is that the contact lenses according to
the invention can be produced from a polymerizable material in a
very simple and efficient way compared with the prior art. Since
the components of a polymerizable material can be purified prior to
aqueous solution preparation, no subsequent purification, such as
in particular complicated extraction of unpolymerized constituents
is needed after crosslinking. In addition, since crosslinking is
carried out in an essentially aqueous solution, a subsequent
solvent exchange or the hydration step is not necessary. Finally,
photo-polymerization is effected within a short period.
[0171] Opening of the mold and removing of the molded article
therefrom can be carried out according to any suitable methods
known to a person skilled in the art.
[0172] Contact lenses obtained from a polymerizable material of the
invention can have various advantageous properties which are
possesed by contact lenses made from crosslinakble PVA. Exemplary
properties include, without limitation, excellent compatibility
with the human cornea, a well-balanced relationship between water
content, oxygen permeability and good mechanical properties, high
resistance to shape changes (even after autoclaving e.g. at about
120.degree. C.). Furthermore, contact lenses obtained from a
polymerizable material of the invention can also have one or more
improved physical properties including stress at break
(N/mm.sup.2), percentage of elongation at break, toughness or
energy to break (N.multidot.mm), and susceptibility to
fracture.
[0173] In still a further aspect, the present invention provides a
method for modifying one or more physical properties of a hydrogel
article obtained from the polymerization of a crosslinkable
polymer, the method comprising the steps of: adding, into a
solution of said crosslinkable polymer, a modifier in an amount
sufficient to modify said one or more physical properties of said
polymeric article, wherein said modifier is selected from the group
consisting of nanoparticles having a hydrophilic surface, a
copolymer having hydrophobic groups or units for imparting at least
one desired physical property to said hydrogel article and
hydrophilic groups or units in an amount sufficient to render it
miscible with the crosslinkable polymer, and mixtures thereof;
mixing thoroughly said modifier and the crosslinkable polymer; and
crosslinking said crosslinkable polymer in the presence of the
modifier to obtain said hydrogel article, wherein the one or more
physical properties are selected from the group consisting of
stress at break (N/mm.sup.2), percentage of elongation at break,
toughness or energy to break (N.multidot.mm), and susceptibility to
fracture.
[0174] The previous disclosure will enable one having ordinary
skill in the art to practice the invention. In order to better
enable the reader to understand specific embodiments and the
advantages thereof, reference to the following non-limiting
examples is suggested. However, the following examples should not
be read to limit the scope of the invention.
EXAMPLE 1
[0175] General Procedures
[0176] Susceptibility to fracture or Pin Hole Test are carried out
as follows: Lenses are punctured with a -22 gauge needle, folded in
half and then rolled 2-3 times between fingers. If a lens does not
fracture, it is given a "Pass" rating.
[0177] The water contents (%) of contact lenses are measured using
an ATAGO CL-1 Refractometer or an ATAGO N2-E Refractometer.
[0178] Tensile properties (stress at break, elongation at break,
modulus, and toughness) are measured using MTS Tester or equivalent
and load Cell 5N, Class 0.5 or equivalent, with a strain rate of
100 mm/minute.
[0179] Nelfilcon (CIBA Vision) is used in the following examples as
a water-soluble crosslinkable polyvinyl alcohol to be blended with
one or more modifiers. Unless otherwise stated, an aqueous solution
of nelfilcon, containing 30% by weight of nelfilcon, 0.5% by weight
of Poloxamer 108, and 0.095% by weight of Irgacure 2959, is used to
prepared a polymerizable material of the invention for making
contact lenses.
[0180] Design of experiment and analysis of experimental results
are performed by using Design-Expert, version, 6.0.0.
EXAMPLE 2
[0181] Vinyl pyrrolidone/vinyl acetate copolymers are obtained from
International Specialty Products. Copolymers with two different
grades are obtained. One grade is W-635 and has a molecular weight
of about 15,000 and is an aqueous solution containing 50% by weight
of copolymer. The other grade is S-630 and has a molecular weight
of about 51,000 and is a dry powder.
[0182] The above two vinyl pyrrolidone/vinyl acetate copolymers are
blended with nelfilcon to prepare a series of samples for making
contact lenses according to a D-Optimal crossed mixture design with
22 points. The composition of each sample is listed in Table 1.
Sample preparation is described as follows. Nelfilcon aqueous
solution (Example 1) is weighed in a capped vial. A vinyl
pyrrolidone/vinyl acetate copolymer is weighed in another vial and
then deionized water is added to the vial to dissolve the
copolymer. The copolymer solution is added to the nelfilcon vial
and mixed thoroughly. Both vinyl pyrrolidone/vinyl acetate
copolymers are soluble in all mixtures. The aqueous solution of the
vinyl pyrrolidone/vinyl acetate copolymer is added to the nelfilcon
and mixed. All solutions are clear.
[0183] Contact lenses are made from the above-prepared aqueous
solution by using plastic contact lens molds capable of casting a
fully formed contact lens. Poly(propylene) molds are filled with
the appropriate amount of aqueous monomer solution. The molds
containing the aqueous solution are cured by UV irradiation (2.5
mW/cm.sup.2) for 10 seconds. Lenses are removed from the molds,
placed in glass vials containing isotonic borate buffered saline
(saline solution contained 0.005% Poloxamer) and then sterilized.
Lens properties are reported in Table 1.
[0184] Experimental results are analyzed using Design-Expert,
version, 6.0.0. It is found that stress at break (SatB) and
elongation at break (EatB) increase as the concentration of
copolymer increases and the modulus decreases as the concentration
of the copolymer increases. The following equations are obtained in
terms of actual components.
SatB=0.009451*(nelfilcon)-0.02778*(water)+0.015882*(copolymer)
Modulus=0.00525*(nelfilcon)-0.00579*(water)-0.00319*(copolymer)
EatB=2.242543*(nelfilcon)-4.11372*(water)+8.844298*(copolymer)
[0185] The SatB and EatB values at zero percent added copolymer are
essentially for the base control polymer and can be determined by
substituting zero for the appropriate terms in these equations. It
can be seen that adding copolymer with minimal water increases the
values of these key polymer performance indicators.
1TABLE 1 Stress Elong. At Sample Nelfilcon Polymer Water Copolymer
At Break Modulus Beak No. (Wt. Fr.) (Wt. Fr.) (Wt. Fr.) Type
(N/mm.sup.2) (N/mm.sup.2) (%) 1 0.8860 0.0102 0.1038 W-635 0.607
0.390 132 2 0.8881 0.0102 0.1017 S-630 0.512 0.366 139 3 0.7212
0.0992 0.1796 W-635 0.274 0.220 158 4 0.7278 0.0989 0.1733 S-630
0.218 0.187 169 5 0.7945 0.1017 0.1038 W-635 0.436 0.320 253 6
0.7998 0.0992 0.1010 S-630 0.532 0.348 297 7 0.8144 0.0101 0.1755
W-635 0.380 0.316 168 8 0.8136 0.0101 0.1763 S-630 0.366 0.319 168
9 0.8339 0.0585 0.1076 W-635 0.529 0.388 154 10 0.8431 0.0557
0.1012 S-630 0.890 0.364 258 11 0.7840 0.0767 0.1393 S-630 0.496
0.309 161 12 0.8517 0.0100 0.1383 W-635 0.455 0.372 263 13 0.7687
0.0551 0.1762 W-635 0.344 0.324 96 14 0.8047 0.0479 0.1474 W-635
0.586 0.342 165 15 0.7580 0.0870 0.1550 W-635 0.618 0.289 292 16
0.8480 0.0103 0.1417 S-630 0.225 0.346 60 17 0.7687 0.0551 0.1762
S-630 0.324 0.301 113 18 0.7946 0.1026 0.1028 S-630 0.611 0.323 170
19 0.7242 0.1003 0.1755 S-630 0.400 0.290 158 20 0.8886 0.0100
0.1014 W-635 0.803 0.477 208 21 0.7866 0.1059 0.1075 W-635 0.856
0.331 210 22 0.8900 0.0099 0.1001 S-630 0.280 0.372 104
EXAMPLE 3
[0186] Two grades, D1 and T5, of dextran are obtained from Amersham
Pharmacia Biotech. D1 grade of dextran has a molecular weight of
about 1000 and T5 grade of dextran has a Molecular weight of about
5000.
[0187] The above two grades of dextran are blended with nelfilcon
to prepare a series of samples for making contact lenses according
to a mixed D-Optimal mixture design with 17 points. The composition
of each of the samples is listed in Table 2. Sample preparation is
the same as described in Example 2. Some solutions (samples 6, 10,
11, and 17-19) are cloudy and the rest solutions are clear.
2 TABLE 2 Composition (Wt. Fraction) Sample No. Nelfilcon Water
Dextran Dextran type 1 0.8800 0.1091 0.0109 D1 2 0.8897 0.1003
0.0100 T5 3 0.7238 0.1772 0.0990 D1 4 0.7220 0.1771 0.1009 T5 5
0.7948 0.1034 0.1018 D1 6 0.7910 0.1045 0.1045 T5 7 0.8111 0.1787
0.0102 D1 8 0.8105 0.1793 0.0102 T5 9 0.8432 0.1014 0.0554 D1 10
0.8404 0.1033 0.0563 T5 11 0.7828 0.1389 0.0783 T5 12 0.8506 0.1392
0.0102 D1 13 0.7402 0.1979 0.0619 D1 14 0.8077 0.1374 0.0549 D1 15
0.7607 0.1386 0.1007 D1 16 0.8530 0.1385 0.0085 T5 17 0.7661 0.1789
0.0550 T5 18 0.7912 0.1054 0.1034 T5 19 0.7218 0.1809 0.0973 T5 20
0.8860 0.1037 0.0103 D1 21 0.7884 0.1062 0.1054 D1 22 0.8875 0.1023
0.0102 T5
[0188] Contact lenses are prepared from the above-prepared aqueous
solution in the same manner as descried in example 2. Lenses are
removed from the molds, placed in glass vials containing isotonic
borate buffered saline (saline solution contained 0.005% poloxomer)
and then sterilized. Lens properties are reported in Table 3.
[0189] Experimental results are analyzed using Design-Expert,
version, 6.0.0. Analysis of data indicates that physical properties
of contact lenses made from nelfilcon can be modified to some minor
extent by blending nelfilcon with dextran.
3TABLE 3 Stress at Elong. at Sample Lens Clarity Break Break
Modulus No. (Visual) (Measured) (N/mm.sup.2) (%) (N/mm.sup.2) 1
Clear 0.20 0.243 87 0.288 2 Clear 0.28 0.303 82 0.344 3 Clear 0.10
0.115 60 0.099 4 Cloudy 25.77 0.192 67 0.165 5 Clear 0.10 0.177 78
0.152 6 Cloudy 34.20 0.113 36 7 Clear 0.19 0.159 58 0.246 8 Clear
0.05 0.126 40 9 Clear 0.16 0.340 113 0.261 10 Cloudy 34.60 0.268 83
0.197 11 Cloudy 34.10 0.055 24 12 Clear 0.33 0.383 144 0.234 13
Clear 0.52 0.359 154 0.227 14 Clear 0.43 0.986 253 0.349 15 Clear
0.09 0.492 134 0.279 16 Clear 0.16 0.789 152 0.450 17 Cloudy 29.80
0.480 92 0.437 18 Cloudy 28.40 0.486 76 0.603 19 Cloudy 25.50 0.746
122 0.567 20 Clear 0.41 0.777 192 0.423 21 Clear 0.27 0.488 107
0.382 22 Clear 1.23 0.691 132 0.465
EXAMPLE 4
[0190] Preparation of Vinyl Pyrrolidone/Acrylate Copolymers
[0191] Synthesis of Poly(NVP/GMA/MMA/BA). A 3-neck flask fitted
with a balloon, paddle stirrer, gas inlet/outlet valves is charged
N-vinylpyrolidone (NVP) (23.845 g), glycidylemethacrylate (GMA)
(8.229 g), butylacrylate (BA) (4.041 g), methylmethacrylate (MMA)
(2.252 g), vazo-52 (0.2051 g) and 325 mL of toluene. The flask is
filled with nitrogen until the attached 9 inch capacity balloon on
the reaction flask is filled. Vacuum is then applied until the
balloon collapsed and the reaction mixture just began to bubble.
This operation is repeated about five times and then the reaction
mixture is blanketed with nitrogen. The reaction mixture is heated
at 55.degree. C. under nitrogen for about 20 hours. Approximately
0.5 mL of reaction mixture is poured into about 10 mL of hexanes
and about 20 mg of the resulting precipitate is dissolved in
chloroform and then cast onto a NaCl disk. The resulting film is
dried at about 60.degree. C. for 5 minutes and then analyzed by
FT-IR. Selected peaks: 2957, 2929, 2873, 1729, 1685, 1460, 1423,
1285, 1270, 1170, 994 cm.sup.-1.
[0192] Conversion of Poly(NVP/GMA/MMA/BA) to a Photo-Curable
Copolymer. Approximately 350 mL of toluene solution containing a
calculated 35 grams of the obtained poly(DMA/GMA/BEA/MMA) is
combined with DABCO (2.166 grams), 4-methoxyphenol (0.518 grams),
and 350 mL of toluene. The reaction mixture is then heated to about
65.degree. C. and then methacrylic acid (48/10 g) is added. The
reaction mixture is then heated to about 80.degree. C. for about 30
hours. The resulting photo-curable copolymer is isolated by pouring
the reaction mixture into about 1500 mL of hexanes. The
precipitated copolymer is dissolved in THF and reprecipitated in
hexanes and then dried for a few days in a vacuum oven.
Approximately 20 mg of sample is dissolved in about 0.5 mL of
chloroform and then a film is cast onto a NaCl disk. The film is
dried at about 50.degree. C. f or 10 minutes. FT-IR analysis showed
characteristic ester and amide CO peaks near 1726 and 1643
cm.sup.-1 respectively. In addition, FT-IR showed a broad OH peak
near 3342, and a peak characteristic of C.dbd.C near 1566
cm.sup.-1.
[0193] The vinyl-substituted vinyl pyrrolidone/acrylate copolymers
are blended with nelfilcon to prepare a series of samples for
making contact lenses according to a D-Optimal mixture design with
14 points. The composition of each of the samples is listed in
Table 4. Sample preparation is described as follows. Nelfilcon
aqueous solution is weighed in a capped vial. A vinyl-substituted
vinyl pyrrolidone/acrylate copolymer is weighed in another vial and
then deionized water is added in the vial to dissolve the
copolymer. The copolymer solution is added to the nelfilcon vial
and mixed thoroughly. All solutions are clear except for the brown
color imparted by the vinyl-substituted vinyl pyrrolidone/acrylate
copolymer.
4 TABLE 4 Composition (Wt. Fraction) Sample No. Nelfilcon Water NVP
copolymer 1 0.5039 0.2992 0.1969 2 0.3007 0.4998 0.1995 3 0.4852
0.3931 0.1217 4 0.5500 0.4001 0.0499 5 0.4552 0.4953 0.0495 6
0.6514 0.2991 0.0495 7 0.4090 0.4353 0.1557 8 0.5748 0.3002 0.1250
9 0.5317 0.3463 0.1220 10 0.4124 0.3923 0.1953 11 0.4500 0.4996
0.0504 12 0.3642 0.4552 0.1806 13 0.5018 0.2997 0.1985 14 0.6521
0.2987 0.0492
[0194] Contact lenses are prepared from the above-prepared aqueous
solution by methods described in Example 2. Lenses are removed from
the molds, placed in glass vials containing isotonic borate
buffered saline (saline solution contained 0.005% poloxomer) and
then sterilized. Lens properties are reported in Table 5.
5TABLE 5 Stress at Max. Break Break Modulus Elong. At Stress. Max.
Elong. Lens Sample No. (N/mm.sup.2) (N/mm.sup.2) Break (%)
(N/mm.sup.2) At Break (%) Clarity.sup.1 1 1.931 1.391 135 2.533 172
2 2 0.558 0.915 62 0.992 90 3 3 1.297 0.904 172 2.309 226 2 4 0.173
37 0.249 63 1 5 0.259 0.244 81 0.370 118 1 6 0.370 0.535 72 0.643
131 1 7 0.906 0.676 102 1.675 179 2 8 1.671 0.927 149 2.895 182 1 9
1.461 0.988 125 2.439 190 2 10 0.948 1.069 83 1.421 120 2 11 0.167
48 0.219 59 1 12 1.279 0.981 121 1.706 157 3 13 2.010 1.327 140
2.800 190 3 14 0.804 0.627 114 1.881 246 1 .sup.1subjective scale:
1 = clear; 2 = slight haze; 3 = hazy
[0195] Experimental results are analyzed using Design-Expert,
version, 6.0.0. It is found that stress at break (SatB), elongation
at break (EatB), and modulus increase as the concentration of
copolymer increases. Lens clarity improves as the amount of
vinyl-substituted vinyl pyrrolidone/acrylate copolymer decreases.
This is probably due to the fact that vinyl pyrrolidone is not
purified before making vinyl-substituted vinyl pyrrolidone/acrylate
copolymer and the vinyl-substituted vinyl pyrrolidone/acrylate
copolymer is brown in color. The following equations are obtained
in terms of actual components:
SatB=-0.001012*A-0.00381423*B+0.015882*C+0.00298 A*C
Modulus=0.009907*A-0.010313*B-0.057295*C
EatB=1.588316*A-66.03316*B-4.128813*C
[0196] wherein A, B, and C are nelfilcon, water, and copolymer
respectively. The lens properties with pure nelfilcon can be
calculated by substituting zero in the equations for water and
copolymer. It can be seen that SatB increases as the water and
copolymer are added to the monomer mixture.
EXAMPLE 5
[0197] Nano-size silica fillers (particles), Aerosil 0.times.50 and
Aerosil 200, are supplied by Degussa. Aerosil 0.times.50 has an
averaged particle size of about 40 nm and Aerosil 200 has an
averaged particle size of about 12 nm.
[0198] A series of samples is prepared as follows. Nelfilcon
aqueous solution is weighed in a capped vial. Nano-size silica
fillers are weighed in another vial and then weighed amount of
nelfilcon is added. The mixture is stirred and centrifuged at 4000
rpm for 15 minutes. The composition of each of the samples is
listed in Table 6.
6 TABLE 6 Composition (Wt. Fraction) Sample Nel- Aerosil Aerosil
Observations after No. filcon 200 0X50 centfifuging * 1 0.9502
0.0498 Large amount of precipitate 2 0.9001 0.0999 Too thick to
centrifuge 3 0.9317 0.0683 Large amount of precipitate 4 0.9010
0.0990 Large amount of precipitate 5 1.0000 6 0.9974 0.0026 No
precipitate 7 0.9946 0.0054 Very small precipitate 8 0.9984 0.0016
Very small precipitate 9 0.9953 0.0047 Very small precipitate * 15
minutes at 4000 rpm
[0199] Contact lenses are prepared from the above-prepared aqueous
solutions from sample Nos. 5-9 using methods described in Example 2
except that the UV irradiance used here is 1.9 mWcm.sup.-2. Lens
properties are reported in Table 7. Lens physical properties such
as stress at break, elongation at break increase with the addition
of fillers. Lens modulus appears to be independent of the presence
of fillers. Susceptibility to fracture (or Pin Hole Test) can be
improved by blending fillers with nelfilcon.
7TABLE 7 Stress Elong. Max. Max. at At Stress Elong. Pin Sample
Break Modulus Break at Break At Break Hole No. (N/mm.sup.2)
(N/mm.sup.2) (%) (N/mm.sup.2) (%) Test* 5 1.778 0.789 206 2.423 424
1 (1.146) (0.094) (130) 6 2.319 0.815 343 2.623 393 4 (2.623)
(0.052) (74) 7 2.958 0.809 345 3.974 404 4 (0.706) (0.085) (42) 8
2.047 0.783 337 2.255 460 4 (0.255) (0.075) (76) 9 1.714 0.847 212
2.670 372 4 (2.217) (0.034) (128) Numbers in the parenthesis are
standard deviations *Pin Hole Test is performed after autoclaving
by puncturing lens center with a needle and folding it over on
itself; 1 = fail, 5 = pass.
EXAMPLE 6
[0200] Two copolymers, GANEX P-904LC and GAFFIX VC-713, are
supplied by International Specialty Products. GANEX P-904LC is an
aqueous solution containing 30% (w/w) of a copolymer of N-vinyl
pyrrolidone (90%) and the C.sub.4 .alpha. olefin 1-butene (10%).
GAFFIX VC-713 is a solution (in ethanol) containing 70% (w/w) of a
copolymer of N-vinyl pyrrolidone, N-vinyl caprolactone, and
dimethylaminoethyl methacrylate.
[0201] The above two copolymers are blended with nelfilcon to
prepare a series of samples for making contact lenses. The
composition of each of the samples is listed in Table 8. Sample
preparation is described as follows. Nelfilcon aqueous solution is
weighed in a capped vial. A copolymer is weighed in another vial
and then added to the nelfilcon vial and mixed thoroughly.
8 TABLE 8 Sample No. Nelfilcon P904LC * VC-713 1156-95- (Wt. Fr.)
(Wt. Fr.) (Wt. Fr.) 1 0.9533 0.0467 2 0.9012 0.0988 3 0.8505 0.1495
4 0.9504 0.0496 5 0.8999 0.1001 6 0.8510 0.1490 Control* 1.0000
Focus Dailies lot 1158643
[0202] Contact lenses are prepared from the above-prepared aqueous
solution by methods described in Example 2 except the monomer
solution is irradiated with UV radiation at 2.5 mWcm.sup.-2. Lenses
are removed from the molds and placed in glass vials containing
isotonic borate buffered saline (saline solution contained 0.005%
poloxomer) and then sterilized by autoclave.
[0203] Lens properties are reported in Table 9. Lens modulus
decreases with increasing concentration of copolymer (VC-713 or
P904-LC). The energy to break (toughness) of all lenses made from
the blends is increased significantly over those of control lenses.
Other physical properties (such as peak stress and elongation at
break) of lenses made from the blends are statistically
significantly better than those of control lenses.
9TABLE 9 Elongation Energy to Center Peak Stress Modulus At Break
Break Diameter Thickness Sample No. (N/mm.sup.2) (N/mm.sup.2) %
(N*mm) (mm) (mm) 1 1.439 0.531 474 17.596 13.95 0.185 2 1.485 0.443
424 14.327 14.00 0.182 3 1.424 0.391 471 14.893 13.91 0.179 4 1.766
0.513 386 14.575 13.97 0.182 5 1.719 0.451 369 12.947 14.01 0.180 6
2.053 0.456 386 15.150 14.02 0.180 Control 0.563 0.313 304 4.819
13.80 0.200 Control is 100% nelfilcon lens
EXAMPLE 7
[0204] A copolymer, GANEX P-904LC, is supplied by International
Specialty Products. GANEX P-904LC is an aqueous solution containing
30% (w/w) of a copolymer of N-vinyl pyrrolidone (90%) and the
C.sub.4 .alpha. olefin 1-butene (10%).
[0205] The compositions of the samples are listed in Table 10 and
are prepared as described in Example 6.
10 TABLE 10 Composition (Wt. Fraction) Sample No. Nelfilcon P-904LC
1 0.8499 0.1501 2 0.9484 0.0516 3 0.8995 0.1005 4 0.8475 0.1525
Control* Focus Dailies, lot 2064670, target power = -3.00
[0206] Contact lenses are prepared from the polymerizable
compositions. Lenses are prepared by methods described in Example
2. Monomer in the molds containing the aqueous solution is cured by
UV irradiation (2.2 mW/cm.sup.2) (for a total of 9 seconds). Mold
halves containing lenses are placed in deionized water to soak for
several seconds and then lenses are removed from the molds and
placed in glass vials containing isotonic borate buffered saline
(saline solution contained 0.005% poloxomer) and then sterilized by
autoclave.
[0207] Extraction studies are carried out as follows. Each lens is
placed in 2.6 g of buffered saline and autoclaved. The saline in
which the lenses are autoclaved is tested for NVP/1-butene
copolymer. In a separate experiment, the lenses are extracted in
saline and then the saline is tested for the presence of the
NVP/1-butene copolymer. The limit of detection is 50 ppm. It is
found that NVP/1-butene copolymer is not extracted from the lenses
either in the autoclave or in a separate saline extraction
experiment.
[0208] Lens properties are reported in Table II. The data in Table
II indicate that the NVP/1-butene copolymer improves the physical
properties (peak stress, elongation at break and toughness of Focus
Dailies lenses. It appears that the presence of the hydrophobic
component (1-butene) may play an important role in improving
physical properties of lenses. It is also technologically
meaningful that the blended copolymer does not extract from the
nelfilcon even though there is no apparent chemical bonding of the
nelfilcon with the copolymer.
11TABLE 11 Peak Elong. At Center Stress Modulus Toughness Break
Diameter Thickness Water Sample No. (N/mm.sup.2) (N/mm.sup.2)
(N*mm) (%) (mm) (mm) (%) 1 1.096 0.406 12.025 391 13.79 0.210 2
70.3 3 74.1 4 76.9 Control* 0.835 0.486 5.847 251 13.80 0.200
70.0
EXAMPLE 8
[0209] Preparation of DMA Copolymer: Poly(DMA/GMA/BEA/MMA)
[0210] Vinyl-substituted Poly(DMA) is prepared by polymerizing
N,N-dimethylacrylamide (DMA) with glycidyl methacrylate (GMA),
methyl methacrylate (MMA), and 2-butoxyethylateacrylate (BEA). A
3-neck flask fitted with a balloon, paddle stirrer, gas
inlet/outlet valves is charged DMA (23.845 g), GMA (8.036 g), BEA
(6.031 g), MMA (2.029 g), vazo-52 (0.2041 g) and 325 mL of toluene.
The flask is filled with nitrogen until the attached 9 inch
capacity balloon on the reaction flask is filled. Vacuum is then
applied until the balloon collapsed and the reaction mixture just
began to bubble. This operation is repeated about five times and
then the reaction mixture is blanketed with nitrogen. The reaction
mixture is heated at 55.degree. C. under nitrogen for about 20
hours. The reaction mixture volume is then adjusted to 400 mL by
the addition of toluene and then approximately 50 mL of the
reaction mixture is poured into 150 mL of hexanes. The resulting
precipitate of Poly(DMA/GMA/BEA/MMA) is dried under vacuum at about
35-40.degree. C. for about one day. About 20 mg of the dried sample
is dissolved in about 0.5 mL of chloroform, cast onto a NaCl disk,
and dried at about 50.degree. C. for about 10 minutes and then
analyzed by FT-IR. Selected peaks: 2932, 2871, 1728, 1642, 1496,
1398, 1355, 1257, 1134, 993 cm.sup.-1.
[0211] Conversion of Poly(DMA/GMA/BEA/MMA) to a Photo-Curable
Copolymer
[0212] Approximately 350 mL of toluene solution containing a
calculated 35 grams of the obtained poly(DMA/GMA/BEA/MMA) is
combined with DABCO (2.11 grams), 4-methoxyphenol (0.509 grams),
and 850 mL of toluene. The reaction mixture is then heated to about
65.degree. C. and then methacrylic acid (48.1 g) is added. The
reaction mixture is then heated to about 80.degree. C. for about 30
hours. The resulting photo-curable copolymer is isolated by pouring
the reaction mixture into about 1500 mL of hexanes. The
precipitated copolymer is dissolved in THF and reprecipitated in
hexanes and then dried for a few days in a vacuum oven.
Approximately 20 mg of sample is dissolved in about 0.5 mL of
chloroform and then a film is cast onto a NaCl disk. The film is
dried at about 50.degree. C. f or 10 minutes. FT-IR analysis showed
characteristic ester and amide CO peaks near 1726 and 1643
cm.sup.-1 respectively. In addition, FT-IR showed a broad OH peak
near 3350, and a peak characteristic of C.dbd.C near 1510 cm.sup.-1
A 30 weight percent solution of the copolymer in water containing
0.033 weight percent Irgacure 2959 had viscosity of 588 cps at
25.degree. C. Contact lenses with water content of about 79 percent
are obtained by photo-curing this solution at about 2.5 mW/cm.sup.2
for 20 seconds.
[0213] Lens Preparation
[0214] The above obtained vinyl-substituted DMA copolymer is
blended with nelfilcon to prepare a series of samples for making
contact lenses according to a D-Optimal crossed mixture design with
14 points. The composition of each of samples is listed in Table
12. Sample preparation is described as follows. Nelfilcon aqueous
solution is weighed in a capped vial. The vinyl-subsituted DMA
copolymer is weighed in another vial and then deionized water is
added in the vial to dissolve the DMA copolymer. The DMA copolymer
solution is added to the nelficon vial and mixed thoroughly. A
clear aqueous solution is obtained.
[0215] Contact lenses are prepared from the above-prepared aqueous
solution according to procedures given in Example 2 except that the
monomer solutions are irradiated with UV radiation at 2.5
mWcm.sup.-2. Lenses are removed from the molds, placed in glass
vials containing isotonic borate buffered saline (saline solution
contained 0.005% poloxomer) and then sterilized.
[0216] Lens properties are reported in Table 12. It appears that
there is no statistically significant model that can be used to
interpret the results. The DMA copolymer appears to influence lens
properties but not in a predictable manner. Some formulations
(e.g., 1, 5, and 8) can be used to prepare lenses which have very
good tensile properties and can pass a pin hole test.
12TABLE 12 Sample Composition (weigh fraction) SatB Modulus Pin
Hole No. Nelfilcon Copolymer water (N/mm.sup.2) (N/mm.sup.2) EatB
(%) Test* 1 0.8083 0.1826 0.0091 0.642 0.369 233 2 2 0.8839 0.1056
0.0105 0.451 0.381 168 2 3 0.7909 0.1531 0.0560 0.606 0.396 133 1 4
0.7983 0.1239 0.0778 0.542 0.283 109 1 5 0.7895 0.1078 0.1027 1.267
0.329 212 2 6 0.7015 0.2024 0.0961 1 7 0.8361 0.1537 0.0102 0.311
0.388 76 2 8 0.8287 0.1119 0.0594 1.062 0.568 272 2 9 0.7345 0.2089
0.0566 0.195 0.269 65 1 10 0.8165 0.1277 0.0558 0.355 0.431 86 2 11
0.7865 0.2034 0.0101 0.590 0.414 157 1 12 0.7899 0.1068 0.1033
0.159 40 2 13 0.6957 0.2039 0.1004 14 0.8918 0.0984 0.0098 0.691
0.466 126 2 *1 = broke; 2 = not broke
EXAMPLE 9
[0217] Preparation of Isocyanate-Capped Poly(urethane)
[0218] Isocyanate-capped poly(urethane) A is prepared as follows.
PEG-1000 (861.30 grams) and TMP (21.67 grams) are combined and
heated at 75.degree. C. The resulting melt is dried over 85 grams
of 3 angstrom molecular sieves for about 24 hours at 60.degree. C.
IPDI (316.90 grams) is mixed with to the PEG/TMP melt and the
resulting mixture is heated at 60.degree. C. for about one hour.
The reaction mixture is then decanted away from the melt and
stirred at 75.degree. C. under nitrogen until the percentage of NCO
in the prepolymer is about 2.12% by weight. The total reaction time
is about 159 hours.
[0219] Isocyanate-capped poly(urethane) B is prepared as follows.
To a 60.degree. C. A melt consisting of PEG-1000 (701.20 grams),
Pluronic 17R.sub.2 (78.46 grams) and TMP (24.77 grams) is added 80
grams of activated molecular sieves (3 angstrom). To the 60.degree.
C. melt is added IPDI (287.16 grams) and the mixture is stirred at
75.degree. C. under nitrogen until the percentage of NCO in the
prepolymer is about 2.0% by weight. The total reaction time is
about 98 hours. A 30 weight percent solution of this sample in
water had a viscosity of 2670 cps.
[0220] Preparation of Photocurable Poly(Urethane) Prepolymer
[0221] The above NCO terminated poly(urethane) (polyurethane
prepolymer) A and B are converted to a TBAM capped poly(urethane) A
and B in approximately 200 gram portions in 1-liter plastic
beakers. To each sample of poly(urethane) is added a calculated
1-equivalent of TBAM. Samples are mixed thoroughly using plastic
rods and then checked by FT-IR. Additional TBAM is added dropwise
until NCO is consumed. Aqueous solutions containing about 30
percent by weight of poly(urethane) are prepared by diluting TBAM
capped poly(urethane) samples with de-ionized water containing
0.05% by weight of Irgacure 2959.
[0222] Lens Preparation
[0223] The above two polyurethane prepolymers, A and B, are blended
with nelfilcon to form a series of samples for making contact
lenses under various irradiation conditions. The composition of
each of the samples is listed in Table 13. Sample preparation is
described as follows. Nelfilcon aqueous solution is weighed in a
capped vial. The polyurethane prepolymer is weighed in another vial
and then added to the nelficon vial and mixed thoroughly. A clear
aqueous solution is obtained.
13 TABLE 13 Half Composition (Wt. Fraction) Curing UV Sample
Polyurethane prepolymer Time Intensity No. Nelfilcon A B (sec)
(mW/cm.sup.2) 1 0.8501 0.1499 6.50 2.26 2 0.8499 0.1501 6.50 2.26 3
0.9437 0.0563 6.50 2.26 4 0.9438 0.0562 6.50 2.26 5 0.8501 0.1499
4.15 2.26 6 0.8499 0.1501 4.15 2.26 7 0.9437 0.0563 4.15 2.26 8
0.9438 0.0562 4.15 2.26 9 0.8501 0.1499 6.50 1.67 10 0.8499 0.1501
6.50 1.67 11 0.9437 0.0563 6.50 1.67 12 0.9438 0.0562 6.50 1.67 13
0.8501 0.1499 4.15 1.67 14 0.8499 0.1501 4.15 1.67 15 0.9437 0.0563
4.15 1.67 16 0.9438 0.0562 4.15 1.67 17 0.9004 0.0996 5.17 1.93 18
0.8992 0.1008 5.17 1.93
[0224] Contact lenses are prepared from the above-prepared samples.
Using methods described in Example 2. The monomer mixture in the
molds containing the sample is cured by a UV lamp for times and
intensities listed in Table 13. Casting mold halves containing
lenses are first placed in deionized water to soak for several
seconds and then lenses are removed from the mold halves. Lenses
are placed in glass vials containing isotonic borate buffered
saline solution contained 0.005% poloxomer) and then autoclaved
prior to measuring physical properties. Lens properties are
reported in Table 14.
[0225] Lens clarity of lenses generally decreases as the
polyurethane level increases. This effect is larger at the higher
polyurethane level for the higher curing times for those lenses
made from a blend of prepolymer A and nelfilcon.
[0226] Peak stress of lenses made from a blend of nelfilcon and
prepolymer A increases slightly as the curing time increases for
the lower UV intensity but is relatively constant for the high UV
intensity. At the low curing time, peak stress of lenses made from
a blend of nelfilcon and prepolymer B increases as the UV intensity
decreases and as the polyurethane level decreases. The situation
reverses at the high curing time.
[0227] Elongation at break of lenses made from a blend of nelfilcon
and prepolymer A increases as the polyurethane level decreases at
the low UV intensity and increases at the high polyurethane level
at the high UV intensity. Elongation at break of lenses made from a
blend of nelfilcon and prepolymer B increases as the polyurethane
level decreases and as the UV intensity increases for the low cure
time. The situation with the high curing time reverses for the
polyurethane level at the low UV intensity and increases at the
high polyurethane level at the high UV intensity.
[0228] Modulus of lenses decreases as the polyurethane level
increases. The effect is greater at the high UV intensity at the
higher polyurethane level. Energy to break (toughness) increases as
the polyurethane level decreases at the low UV intensity. Energy to
break (toughness) increases as the polyurethane level decreases at
the low curing time. The reverse is true at the high curing
time.
14TABLE 14 Center Peak Elongation Energy to Lens Diameter Thickness
Stress at Break Modulus Break Sample No. Clarity.sup.a (mm) (mm)
(N/mm.sup.2) (%) (N/mm.sup.2) (N*mm) 1 3 13.98 0.267 1.418 562
0.356 17.425 2 3 13.93 0.274 2.312 442 0.356 14.482 3 1 13.85 0.263
1.560 371 0.367 14.344 4 1 13.83 0.269 1.375 421 0.399 18.688 5 2
13.96 0.268 1.205 385 0.376 15.701 6 2 14.01 0.264 1.268 379 0.344
11.004 7 1 13.86 0.272 1.430 368 0.415 16.335 8 1 13.89 0.268 1.501
398 0.370 17.719 9 3 13.96 0.270 0.972 288 0.325 8.575 10 3 13.96
0.270 1.374 394 0.324 15.428 11 1 13.91 0.269 1.366 428 0.398
19.492 12 1 13.91 0.277 1.117 338 0.377 12.422 13 2 14.00 0.272
1.608 274 0.311 6.756 14 2 14.00 0.268 0.950 297 0.293 7.738 15 1.5
14.03 0.278 1.272 424 0.382 19.409 16 1.5 14.05 0.267 1.819 451
0.395 22.700 17 1.5 13.99 0.272 1.594 392 0.382 18.989 18 1.5 14.05
0.275 1.410 329 0.372 13.401 Control.sup.b 13.80 0.266 0.370 276
0.276 3.402 .sup.aVisual clarity scale: 1 = clear; 5 = hazy
.sup.bFocus Dailies lenses (-1.00 D)
EXAMPLE 10
[0229] Polyurethane prepolymers A and B are prepared as described
in Example 9. The polyurethane prepolymers A and B are blended with
nelfilcon to form a series of samples for making contact lenses
under various curing time conditions. The composition of each of
the samples is listed in Table 15. Samples are prepared as
described in Example 9.
15 TABLE 15 Composition (Wt. Fraction) Sample Polyurethane
Polyurethane Half Cure Time No. Nelfilcon prepolymer A prepolymer B
(second) 1 0.8999 0.1001.sup.a 4 2 0.8996 0.1004.sup.b 4 3 0.9498
0.0502.sup.a 4 4 0.9499 0.0501.sup.b 4 5 0.8999 0.1001.sup.a 3 6
0.8996 0.1004.sup.b 3 7 0.9498 0.0502.sup.a 3 8 0.9499 0.0501.sup.b
3 9 0.9249 0.0751.sup.a 3.5 10 0.9249 0.0751.sup.b 3.5
[0230] Contact lenses are prepared from the above-prepared samples
using methods described in Example 2. The UV irradiation is t 2
mWcm.sup.-2 for times listed in Table 2. Lenses are placed in glass
vials containing isotonic borate buffered saline (saline solution
contained 0.005% poloxomer) and then autoclaved prior to measuring
physical properties.
[0231] Lens properties are reported in Table 16. All lenses made
from a blend of nelfilcon have values of elongation at break and
energy to break much greater than those control lenses.
16TABLE 16 Center Peak Elongation at Energy to Sample Diameter
Thickness Stress Break Modulus Break No. Clarity.sup.a (mm) (mm)
(N/mm.sup.2) (%) (N/mm.sup.2) (N*mm) 1 1.5 13.84 0.272 1.159 369
0.519 16.223 2 1.5 13.90 0.274 0.698 267 0.495 4.443 3 1 13.74
0.272 1.486 361 0.597 18.659 4 1 14.00 0.264 0.896 237 0.455 6.147
5 2 13.96 0.266 1.166 344 0.418 14.158 6 2 13.78 0.266 1.288 319
0.444 12.884 7 1 13.76 0.272 0.896 246 0.456 7.664 8 1 13.89 0.261
1.044 285 0.446 9.608 9 1 13.82 0.268 1.453 224 0.576 9.230 10 1
13.98 0.274 1.682 294 0.548 15.488 Control.sup.b 13.80 0.226 0.436
175 0.378 2.680 .sup.aVisual clarity scale: 1 = clear; 5 = hazy
.sup.bFocus Dailies lenses, power -1.00 D
EXAMPLE 11
[0232] Preparation of vinyl-substituted DMA copolymer.
Vinyl-substituted DMA copolymer is prepared as described in Example
8.
[0233] Preparation of polyurethane prepolymer. NCO terminated
poly(urethane) is prepared as follows. PEG-1000 (962.6 grams), TMP
(32.28 grams), and IPDI (222.3 grams) are combined in a round flask
which is equipped with a gas inlet valve and a paddle stirring
device. The flask is placed in a preheated 75.degree. C. oil bath
and nitrogen is passed through the reaction vessel for several
minutes. The reaction mixture is then heated under nitrogen at
about 75.degree. C. for about 107 hours. The conversion of NCO is
monitored by titration.
[0234] The above NCO terminated poly(urethane) is converted to TBAM
capped poly(urethane) in approximately 200 gram portions in 1-liter
plastic beakers. To each sample of poly(urethane) is added a
calculated 1-equivalent of TBAM. Samples are mixed thoroughly using
plastic rods and then checked by FT-IR. Additional TBAM is added
dropwise until NCO is consumed. Aqueous solutions containing about
30 weight percent poly(urethane) and 0.05 weight percent Irgacure
2959 are prepared by adding de-ionized water and Irgacure 2959 into
each sample.
[0235] The above DMA copolymer and polyurethane prepolymer are
blended with nelfilcon to form a series of samples (Table 17) for
making contact lenses according to a D-Optimal crossed mixture
design with 14 points. The results show, upon regression analysis,
that break stress over that expected for pure nelfilcon increases
as the amount of DMA and polyurethane copolymers increase. The same
is true for elongation at break.
17 TABLE 17 Composition (Wt. Fraction) Polyurethane Sample No.
Nelfilcon DMA copolymer prepolymer 1 0.8525 0.0985 0.0490 2 0.8958
0.0580 0.0462 3 0.8869 0.0693 0.0438 4 0.9289 0.0553 0.0158 5
0.8798 0.1079 0.0123 6 0.9400 0.0413 0.0187 7 0.8798 0.0827 0.0375
8 0.9249 0.0484 0.0267 9 0.9109 0.0558 0.0333 10 0.8731 0.0976
0.0293 11 0.8815 0.1067 0.0118 12 0.8995 0.0497 0.0508 13 0.8481
0.1019 0.0500 14 0.9680 0.0185 0.0135
[0236] Nelfilcon aqueous solution is weighed in a capped vial. The
polyurethane prepolymer and DMA copolymer are weighed in separated
vials and then sufficient deionized water is added to make 30% by
weight solutions. The DMA copolymer aqueous solution and the
polyurethane prepolymer aqueous solution are added to the nelficon
vial and mixed thoroughly. All solutions are hazy but all lenses
are clear.
[0237] Contact lenses are prepared from the above-prepared sample
using methods listed in Example 2. Monomer mixtures are irradiated
at about 2.2 mWcm.sup.-2 for about 10 seconds. Lenses are removed
from the molds, placed in glass vials containing isotonic borate
buffered saline (saline solution contained 0.005% poloxomer) and
then sterilized. Lens properties are reported in Table 18.
18TABLE 17 Elongation At Max. Break Max. Elongation Stress at Break
Modulus Break Stress at Break Sample No. (N/mm.sup.2) (N/mm.sup.2)
(%) (N/mm.sup.2) (%) 1 1.116 0.647 290 1.784 330 2 1.211 0.769 330
2.191 347 3 1.378 0.780 248 2.280 383 4 0.780 0.868 119 1.994 351 5
1.536 0.803 224 2.207 378 6 1.080 0.749 217 1.778 404 7 0.622 0.579
110 2.014 239 8 1.833 0.884 221 2.058 361 9 1.468 0.899 217 1.908
342 10 1.790 0.766 251 2.414 349 11 2.227 0.679 273 4.493 373 12
1.292 0.943 192 2.014 347 13 1.568 0.718 277 2.230 378 14 1.535
0.920 271 2.037 385
EXAMPLE 12
[0238] Preparation of vinyl-substituted DMA copolymer.
Vinyl-substituted DMA copolymer is Prepared as follows.
[0239] A 3-neck flask fitted with a balloon, paddle stirrer, gas
inlet/outlet valves is charged DMA (23.812 g), GMA (8.079 g), BEA
(2.021 g), MMA (6.100 g), vazo-52 (0.2145 g) and 225 mL of toluene.
The flask is filled with nitrogen until the attached 9 inch
capacity balloon on the reaction flask is filled. Vacuum is then
applied until the balloon collapsed and the reaction mixture just
began to bubble. This operation is repeated about five times and
then the reaction mixture is blanketed with nitrogen. The reaction
mixture is heated at 55.degree. C. under nitrogen for about 20
hours. The poly(DMA/GMA/BEA/MMA) is precipitated by pouring the
toluene solution into 1500 mL of hexanes. The copolymer is then
dissolved in about 750 mL of toluene and converted to photo-curable
copolymer as described below.
[0240] Conversion of Poly(DMA/GMA/BEA/MMA) to a Photo-Curable
Copolymer
[0241] Approximately 700 mL of toluene solution containing a
calculated 35 grams of the obtained poly(DMA/GMA/BEA/MMA) is
combined with DABCO (1.172 grams), 4-methoxyphenol (0.209 grams),
and 500 mL of toluene. The reaction mixture is then heated to about
65.degree. C. and then methacrylic acid (24.36 g) is added. The
reaction mixture is then heated to about 80.degree. C. for about 30
hours. The resulting photo-curable copolymer is isolated by pouring
the reaction mixture into about 1000 mL of hexanes and dried in a
vacuum oven at about 30.degree. C. for a few hours. The
photo-curable copolymer is then dissolved in THF and reprecipitated
in about 1 liter of hexanes. The precipitated copolymer is
dissolved in THF and re-precipitated in hexanes and then dried for
a few days in a vacuum oven. Approximately 20 mg of sample is
dissolved in about 0.5 mL of chloroform and then a film is cast
onto a NaCl disk. The film is dried at about 50.degree. C. f or 10
minutes. FT-IR analysis showed characteristic ester and amide CO
peaks near 1726 and 1643 cm.sup.-1 respectively.
[0242] A 30 weight percent solution of the copolymer in water
containing 0.033 weight percent Irgacure 2959 had viscosity of 1270
cps at 25.degree. C. Contact lenses with water content of about 74
percent are obtained by photo-curing this solution at about 2.5
mW/cm.sup.2 for 20 seconds.
[0243] Preparation of polyurethane prepolymer. NCO terminated
poly(urethane) is prepared as follows. PEG-1000 is dried over 3A
molecular sieves at 65.degree. C. for about 4 days prior to use. A
ratio of sieves to PEG is about 1:10. PEG-1000 (962.6 grams), TMP
(32.28 grams), and IPDI (222.3 grams) are combined in a round flask
that is equipped with a gas inlet valve and a paddle-stirring
device. The flask is placed in a preheated 75.degree. C. oil bath
and nitrogen is passed through the reaction vessel for several
minutes. The reaction mixture is then heated under nitrogen at
about 75.degree. C. for about 107 hours. The conversion of NCO is
monitored by titration.
[0244] The above NCO terminated poly(urethane) is converted to TBAM
capped poly(urethane) in approximately 200 gram portions in 1-liter
plastic beakers. To each sample of poly(urethane) is added a
calculated 1-equivalent of TBAM. Samples are mixed thoroughly using
plastic rods and then checked by FT-IR. Additional TBAM is added
dropwise until NCO is consumed. Aqueous solutions containing about
30 weight percent poly(urethane) and 0.05 weight percent Irgacure
2959 are prepared by adding de-ionized water and Irgacure 2959 into
each sample.
[0245] The above DMA copolymer and polyurethane prepolymer are
blended with nelfilcon to form a series of samples (Table 19) for
making contact lenses.
19 TABLE 19 Composition (Wt. Fraction) Polyurethane DMA DMA
copolymer Sample No. Nelfilcon prepolymer copolymer type 1 0.8388
0.1088 0.0524 1310-2 2 0.7945 0.1010 0.1045 1297-90 3 0.7936 0.1032
0.1032 1310-2 4 0.8513 0.0506 0.0981 1310-2 5 0.8452 0.0524 0.1024
1297-90 6 0.8421 0.1039 0.0540 1297-90 7 0.8961 0.1039 8 0.8942
0.0590 0.0468 1297-90 9 0.9043 0.0957 1297-90 10 0.9032 0.0968
1310-2 11 0.8949 0.0535 0.0516 1310-2 12 0.8907 0.1093 13 0.8339
0.0822 0.0839 1297-90 14 0.8358 0.0829 0.0813 1310-2 15 0.8619
0.0711 0.0670 1297-90 16 0.8668 0.0680 0.0652 1310-2 17 0.8656
0.0946 0.0398 1297-90 18 0.8933 0.1067 19 0.8977 0.1023 1310-2 20
0.8994 0.1006 1297-90 21 0.7992 0.0997 0.1011 1310-2 22 0.8928
0.1072
[0246] Nelfilcon aqueous solution is weighed in a capped vial. The
polyurethane prepolymer and DMA copolymer are weighed in separated
vials and then sufficient deionized water is added to make 30% by
weight solutions. The DMA copolymer aqueous solution and the
polyurethane prepolymer aqueous solution are added to the nelficon
vial and mixed thoroughly.
[0247] Contact lenses are prepared from the above-prepared samples
using methods described in Example 2. Monomer solutions are
irradiated at about 2.2 mWcm.sup.-2 for about 10 seconds. Lenses
are removed from the molds, placed in glass vials containing
isotonic borate buffered saline (saline solution contained 0.005%
poloxomer) and then sterilized. Lens properties are reported in
Table 20. The regression analysis shows that the break stress
increases as the concentration of the urethane and DMA copolymer
increases. This indicates that properties of pure nelfilcon have
been improved by the addition of these components.
20 TABLE 20 Stress at Break Elongation at Break (N/mm.sup.2) (%)
Modulus Pin Hole Lens Sample No. Average Maximum Average Maximum
(N/mm.sup.2) Test.sup.1 Clarity.sup.2 1 1 1 1 1 1 1 1 2 1.006 1.479
125 146 0.761 3 1 3 2 1 4 5 1.655 3.101 199 345 0.793 4 1 6 0.986
1.561 149 260 0.792 4 1 7 2.181 2.181 284 284 0.608 1 2 8 0.700
1.010 112 126 0.564 1 1 9 1.651 2.198 176 208 0.722 1.5 1 10 1.707
2.456 216 286 0.748 1 1 11 1.118 1.487 148 186 0.665 1 1 12 1 2 13
1.000 1.706 140 254 0.651 3 1 14 1.531 1.688 240 314 0.697 1 1 15
1.372 2.372 189 336 0.693 1 1 16 0.439 0.475 89 104 0.551 1 1 17
0.437 0.849 81 172 0.485 4 1 18 0.801 1.313 150 224 0.527 5 3 19
1.356 2.237 177 360 0.740 1 1 20 1.401 2.296 142 192 0.754 4 1 21
0.671 1.459 95 190 0.708 2 1 22 2.223 3.122 246 312 0.650 1 3
Control 0.939 1.273 303 377 0.522 * Focus Dailies Lenses (-1.00 D)
.sup.1Pin Hole Test: 1 = very good, 5 = fail .sup.2This is visual
clarity after autoclaving; 1 = clear, 5 = hazy
EXAMPLE 13
[0248] Poly N-vinyl pyrrolidone (NVP) polymers, PVK-15 and PVK-30,
are supplied by International Specialty Products. The NVP polymers
are used as 30% (w/w/) solutions in deionized water. The PVK-15 has
a molecular weight of about 9,700 and the PVK-30 has a molecular
weight of about 67,000.
[0249] The NVP polymers are blended with nelfilcon to prepare a
series of samples for making contact lenses. The composition of
each of the samples is listed in Table 21. Sample preparation is
described as follows. Nelfilcon aqueous solution (Example 1) is
weighed in a capped vial. The NVP polymer is weighed in another
vial. The NVP polymer solution is added to the nelfilcon vial and
mixed thoroughly.
[0250] Contact lenses are prepared from the above-prepared aqueous
solution according methods described in Example 2. Monomer
solutions are irradiated at 1.9 mWcm.sup.-2 for 10 seconds. Lenses
are placed in glass vials containing isotonic borate buffered
saline (saline solution contained 0.005% poloxomer) and then
sterilized by autoclave.
[0251] Lens properties are reported in Table 21. All lenses are
clear after autoclaving. Lens properties (stress at break,
elongation at break and modulus) decrease linearly with increasing
content of NVP polymer. The diminution of lens properties (stress
at break, elongation at break and modulus) is greater for the NVP
polymer having a higher molecular weight. This behavior contrasts
with behavior, shown previously, of copolymers of N-vinyl
pyrrolidone with hydrophobic comonomers such as vinyl acetate and
1-butene. The hydrophobic comonomers add reinforcement as shown by
the increases in one or more key lens properties.
21 TABLE 21 Composition Center Stress at Elongation (Wt. Fraction)
Diameter Thickness Break at Break Modulus Sample No. Nelfilcon NVP
polymer (mm) (mm) (N/mm.sup.2) (%) (N/mm.sup.2) 1 0.8983
0.1017.sup.a 13.98 0.267 1.418 562 0.356 2 0.7953 0.2047.sup.a
13.93 0.274 2.312 442 0.356 3 0.7057 0.2943.sup.a 13.85 0.263 1.560
371 0.367 4 0.9004 0.0996.sup.b 13.83 0.269 1.375 421 0.399 5
0.8002 0.1998.sup.b 13.96 0.268 1.205 385 0.376 6 0.6999
0.3001.sup.b 14.01 0.264 1.268 379 0.344 Control 1.0000 13.80 0.266
0.370 276 0.276 .sup.aPVK-15 .sup.bPVK-30
[0252] Evidently the hydrophobic groups are required to give
reinforcement. The diminution of properties with the pure n-vinyl
pyrrolidone polymer blend with nelfilcon could result from the
decrease in cross-link density since these polymers are not
co-curable. However, the dilution of cross-link density does not
explain the increase in physical properties when nelfilcon is
blended with non-curing N-vinyl pyrrolidone/hydrophobic monomer
copolymers.
* * * * *