Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-06-16
2001-10-16
Michl, Paul R. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
active
06303687
ABSTRACT:
The invention relates to a novel process for the production of mouldings, in particular contact lenses, in which a crosslinkable polymer or a crosslinkable polymer mixture comprising crosslinkable groups, acidic groups and/or basic groups is crosslinked in solution, and to mouldings, in particular contact lenses, which are obtainable by this process.
The present invention also relates to novel crosslinkable polymers which can be employed in the 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. These are, in particular, crosslinkable polymers comprising units containing a crosslinkable group in addition to units containing an acidic group, crosslinkable polymers comprising units containing a crosslinkable group in addition to units containing a basic group, and novel crosslinkable polymers comprising units containing a crosslinkable group in addition to units containing an acidic group and units containing a basic group, and furthermore crosslinked polymers, either homopolymers or copolymers, made from these novel crosslinkable polymers, a process for the preparation of the novel crosslinkable polymers and the homopolymers and copolymers obtainable therefrom, mouldings made from said homopolymers or copolymers, in particular contact lenses made from these homopolymers or copolymers, and a process for the production of contact lenses using the said homopolymers or copolymers.
The novel crosslinkable polymers must, as mentioned, comprise units containing crosslinkable groups. The term crosslinkable groups is taken to mean conventional crosslinkable groups which are well-known to the person skilled in the art, for example photo crosslinkable or thermally crosslinkable groups. Particularly suitable crosslinkable groups are those as have already been proposed for the preparation of contact-lens materials. These include, not exclusively, in particular groups containing a carbon-carbon double bond. However, in order to demonstrate the variety of crosslinkable groups which are suitable, crosslinking mechanisms which may be mentioned here merely by way of example, are free-radical polymerization, 2+2 cycloaddition, Diels-Alder reaction, ROMP (ring opening metathesis polymerization), vulcanization, cationic crosslinking and epoxy curing.
In addition to the units containing a crosslinkable group, the novel crosslinkable polymers must also comprise a group which has an acid functionality or additionally must comprise a group which has a basic functionality.
However, it is also possible for the crosslinkable polymer to comprise all three units, so that all three groups are present, namely a crosslinkable group, an acidic group and a basic group. In this case, the polymers are intramolecular salts.
Preference is given to crosslinkable polymers comprising units containing a crosslinkable group and an acidic group and units containing a crosslinkable group and a basic group. In this case, a mixture of these two crosslinkable polymers is preferably crosslinked.
The present invention relates, in particular, to crosslinkable polymers in which the linking of these units to the starting polymer backbone takes place covalently, so that these groups are bonded irreversibly.
Suitable starting polymers here are all polymers based on polyhydroxyl compounds, in particular those having a 1,3-diol backbone, especially polyvinyl alcohol.
In a polyvinyl alcohol of this type, a certain percentage of the 1,3-diol units has, in accordance with the invention, been modified to give a 1,3-dioxane containing, in the 2-position, a crosslinkable radical or a radical containing an acidic group or a basic group. These radicals are, in particular, aminoalkyl radicals with either a crosslinkable group or an acidic group bonded to the nitrogen atom. The present invention likewise relates to crosslinked homopolymers or copolymers of said crosslinkable polymers, to a process for the preparation of the novel crosslinkable polymers and the homopolymers and copolymers obtainable therefrom, to mouldings made from such homopolymers or copolymers, in particular contact lenses made from these homopolymers or copolymers, and to a process for the production of contact lenses using said homopolymers or copolymers.
The novel crosslinkable polymer is preferably a derivative of a polyvinyl alcohol having a mean molecular weight of at least about 2000 which comprises, as units containing a crosslinkable group, in particular units of the formula I
in which R is alkylene having up to 12 carbon atoms, R
1
is hydrogen or lower alkyl, and R
2
is an olefinically unsaturated, electron-withdrawing, copolymerizable radical, preferably having up to 25 carbon atoms, and R
3
is hydrogen, a C
1
-C
6
alkyl group or a cycloalkyl group.
R
2
is, for example, an olefinically unsaturated acyl radical of the formula R
4
—CO—, in which R
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. In another embodiment, the radical R
2
is a radical of the formula II
—CO—NH—(R
5
—NH—CO—O)
q
—R
6
—O—CO—R
4
(II)
in which q is zero or one, and R
5
and R
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
4
is as defined above.
Preferred units of the formula I are units of the formula III
in which R is lower alkylene, R
1
is hydrogen or lower alkyl, p has the value zero or one, q has the value zero or one, R
4
is an olefinically unsaturated, crosslinkable radical having 2 to 8 carbon atoms, and R
5
and R
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.
Alkylene R has 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.
R
1
is preferably hydrogen or lower alkyl having up to seven, in particular up to four, carbon atoms, in particular hydrogen.
Lower alkylene R
5
or R
6
preferably has 2 to 6 carbon atoms and is, in particular, linear. Suitable examples include propylene, butylene, hexylene, dimethylethylene and, particularly preferably, ethylene.
Arylene R
5
or R
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.
A saturated bivalent cycloaliphatic group R
5
or R
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.
The arylene unit of alkylenearylene or arylenealkylene R
5
or R
6
is preferably phenylene, unsubstituted or substituted by lower alkyl or lower alkoxy, and th
Gorman Jr. Robert J.
Meece R. Scott
Michl Paul R.
Novartis AG
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