Crosslinked polymers

Details Crosslinked polymers Crosslinked polymers

1999-01-22

2001-07-24

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C522S085000, C522S086000, C526S304000, C525S059000, C525S061000, C525S057000

Reexamination Certificate

active

06265509

ABSTRACT:

The invention relates to a novel process for the production of mouldings, in particular contact lenses, in which a prepolymer comprising units containing a crosslinkable group and at least one unit containing a modifier is crosslinked in solution, and to mouldings, in particular contact lenses, which are obtainable by this process.
The present invention also relates to novel prepolymers which can be employed in this crosslinking process, in particular those based on starting polymers containing functional groups, for example hydroxyl groups, on the polymer chain or functional groups, for example imino groups, in the polymer chain or functional groups bonded to the polymer skeleton via a bridge, where these functional groups allow covalent bonds to compounds containing a crosslinkable modifier group or another modifier group. These starting polymers are, in particular, polyhydroxyl compounds having a 1,2- and/or 1,3-diol structure, such as polyvinyl alcohol, or hydrolysed copolymers of vinyl acetate, for example copolymers with vinyl chloride, N-vinylpyrrolidone, etc. The invention furthermore relates to crosslinked polymers, either homopolymers or copolymers, made from these novel prepolymers, to a process for the preparation of the novel prepolymers and the homopolymers and copolymers obtainable therefrom, to mouldings made from said homopolymers or copolymers, in particular contact lenses made from these homopolymers or copolymers, and to a process for the production of contact lenses using the said homopolymers or copolymers.
The starting polymers are, in particular, derivatives of polyvinyl alcohol or copolymers of vinyl alcohol which contain, for example, a 1,3-diol skeleton. The crosslinkable group or the further modifier can be bonded to the starting polymer skeleton in various ways, for example through a certain percentage of the 1,3-diol units being modified to give a 1,3-dioxane which contains a crosslinkable radical or a further modifier in the 2-position.
Another possibility is for a certain percentage of hydroxyl groups in the starting polymer to be esterified by means of an unsaturated organic acid, these ester-bonded radicals containing a crosslinkable group.
In the case of a radical which has been modified to give a 1,3-dioxane, the novel prepolymer is preferably a derivative of polyvinyl alcohol which has a mean molecular weight of at least about 2000 and comprises units which contain a crosslinkable group and a further modifier. The further modifier serves, inter alia, for weighting, which improves the mechanical properties of die moulding, and can contain, for example, an acid or base functionality.
Units containing a crosslinkable group conform, in particular, to the formula I
in which
R is a bivalent radical of a C
1
-C
12
alkane,
R
1
is hydrogen, a C
1
-C
6
alkyl radical or a cycloalkyl radical,
R
2
is hydrogen or a C
1
-C
6
alkyl radical,
group if n=0, or the
bridge if n=1,
R
4
is hydrogen or C
1
-C
4
alkyl,
n is zero or 1, preferably 0, and
R
16
and R
17
, independently of one another, are hydrogen, C
1
-C
8
alkyl, aryl or cyclohexyl.
Units containing a further modifier conform, in particular, to the formula II
in which
R
1
is hydrogen, a C
1
-C
6
alkyl radical or a cycloalkyl radical,
R
5
is a monovalent or bivalent radical of a C
1
-C
8
alkane or a monovalent or bivalent radical of a C
2
-C
8
olefin,
R
6
is a group of the formula —(—NH—CO—R
7
)
o
(R
8
)
p
or —N(R
9
)
2
,
R
7
is an unsubstituted or substituted monovalent or bivalent radical of a C
1
-C
8
alkane,
R
8
is a heterocyclic group,
R
9
is hydrogen or a C
1
-C
6
alkyl radical,
n is zero or 1, and
o and p, independently of one another, are zero or 1.
R in the formula I as a bivalent radical of a C
1
-C
12
alkane is a linear or branched radical, in particular a radical of methane, ethane, n- or isopropane, n-, sec- or tert-butane, n- or isopentane, hexane, heptane or octane. Preferred radicals contain one to four carbon atoms, in particular one carbon atom.
R
1
and R
2
in the formula I and R
1
and R
9
in the formula II as a C
1
-C
6
alkyl radical are, for example, a methyl, ethyl, propyl or butyl radical. R
1
and R
2
are preferably each hydrogen.
R
4
in the formula I as a C
1
-C
4
alkyl radical is, for example, an n-butyl, n- or isopropyl or ethyl radical, in particular a methyl radical.
R
5
in the formula II as a radical of a C
2
-C
8
olefin is a linear or branched radical, for example a radical of propene, 1-butene, 2-butene, methylpropene, 4-ethyl-2-hexene or 2-methylpentene.
R
5
in the formula II as a radical of a C
1
-C
8
alkane is a linear or branched radical, for example a radical of methane, ethane, n- or isopropane, n-, sec- or tert-butane, n- or isopentane, hexane, heptane or octane.
R
7
in the formula II as a monovalent or bivalent radical of a C
1
-C
8
alkane is a linear or branched radical, for example a radical of methane, ethane, n- or isopropane, n-, sec- or tert-butane, n- or isohexane, heptane or octane.
R
8
in the formula II as a heterocyclic group is, in particular, a radical of a five-membered heterocyclic ring containing one ring member other than carbon, such as —S—, —O— or —NH—, for example furan, thiophene, pyrrole, pyrrolidone, pyroglutamic acid, maleimides of the formula
(in which R
10
and R
11
, independently of one another, are hydrogen, C
1
-C
4
alkyl, in particular methyl, or aryl, such as phenyl, or halogen, such as F, Cl or Br, preferably hydrogen or methyl), coumarone, thiocoumarone or indole; a five-membered heterocylic ring containing two ring members other than carbon, such as —O—, —S— or —NH—, for example oxazole, isoxazole, thiazole, imidazole, hydantoin of the formula
(in which R
12
, R
13
and R
14
, independently of one another, are hydrogen or a C
1
-C
6
alkyl group which is unsubstituted or monosubstituted or polysubstituted by, for example, COOH or COO(C
1
-C
4
alkyl)) or pyrazole; a five-membered heterocyclic ring containing three or more ring members other than carbon, such as —O— or —NH—, for example furazan, 1,2,3-triazole, 1,2,4-triazole, 1,3,4-triazole or tetrazole; a six-membered heterocyclic ring containing one ring member other than carbon, for example —O—, —S— or —NH—, for example pyran, thiopyran, pyridine or quinoline; or a six-membered heterocyclic ring containing more than one ring member other than carbon, such as —N—, for example diazines, such as oiazine, miazine, dihydrouracil of the formula
(in which R
14
is as defined above) or piazine, vicinal, asymmetrical or symmetrical triazine or 1,2,3,4-triazine, 1,2,3,5-triazine or 1,2,4,5-triazine.
Preferred heterocyclic groups are radicals of five-membered heterocyclic rings containing one ring member other than carbon, in particular —NH—, in particular those of maleimide and pyrrolidone.
R
16
and R
17
in the formula I as a C
1
-C
8
alkyl group are a linear or branched group, for example one of the following: octyl, hexyl, pentyl, butyl, propyl, ethyl, methyl, 2-propyl, 2-butyl or 3-pentyl. R
16
is preferably hydrogen or the CH
3
group, and R
17
is preferably a C
1
-C
4
alkyl group.
R
16
and R
17
as aryl are preferably phenyl.
All these groups can be monosubstituted or polysubstituted, examples of suitable substituents being the following: C
1
-C
4
alkyl, such as methyl, ethyl or propyl, —COOH, —OH, —SH, C
1
-C
4
alkoxy (such as methoxy, ethoxy, propoxy, butoxy or isobutoxy), —NO
2
, —NH
2
, —NH(C
1
-C
4
alkyl), —NH—CO—NH
2
, —N(C
1
-C
4
alkyl)
2
, phenyl (unsubstituted or substituted by, for example, —OH or halogen, such as Cl, Br or especially I), —S(C
1
-C
4
alkyl), a 5- or 6-membered heterocyclic ring, such as, in particular, indole or imidazole, —NH—C(NH)—NH
2
, phenoxyphenyl (unsubstituted or substituted by, for example, —OH or halogen, such as Cl, Br or especially I), an olefinic group, such as methylene or vinyl, and CO—NH—C(NH)—NH
2
.
Preferred substituents are lower alkyl, which here, as elsewhere in this description, is preferably C
1
-C
4
alkyl, C
1
-C
4
alkoxy, COOH, SH, —NH
2
, —NH(C
1
-C
4
alkyl), —N(C
1
-C
4
alkyl)
2
or h

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