Crosslinked polymers

Details Crosslinked polymers Crosslinked polymers

1997-07-30

1999-08-03

Smith, Jeffrey

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

526304, C08F23402, C08F22058

Patent

active

059326743

DESCRIPTION:

BRIEF SUMMARY
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 the moulding, and can contain, for example, an acid or base functionality.
Units containing a crosslinkable group conform, in particular, to the formula I ##STR1## in which R is a bivalent radical of a C.sub.1 -C.sub.12 alkane, radical, ##STR2## group if n=0, or the ##STR3## bridge if n=1, R.sub.4 is hydrogen or C.sub.1 -C.sub.4 alkyl, -C.sub.8 alkyl, aryl or cyclohexyl. II ##STR4## in which R.sub.1 is hydrogen, a C.sub.1 -C.sub.6 alkyl radical or a cycloalkyl radical, a monovalent or bivalent radical of a C.sub.2 -C.sub.8 olefin, (R.sub.8).sub.p or --N(R.sub.9).sub.2, of a C.sub.1 -C.sub.8 alkane,
R in the formula I as a bivalent radical of a C.sub.1 -C.sub.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.sub.1 and R.sub.2 in the formula I and R.sub.1 and R.sub.9 in the formula II as a C.sub.1 -C.sub.6 alkyl radical are, for example, a methyl, ethyl, propyl or butyl radical. R.sub.1 and R.sub.2 are preferably each hydrogen.
R.sub.4 in the formula I as a C.sub.1 -C.sub.4 alkyl radical is, for example, an n-butyl, n- or isopropyl or ethyl radical, in particular a methyl radical.
R.sub.5 in the formula II as a radical of a C.sub.2 -C.sub.8 olefin is a linear or branched radical, for example a radical of propene, 1-butene, 2-butene, methylpropene, 4-ethyl-2-hex

REFERENCES:
patent: 4347198 (1982-08-01), Ohkada et al.
patent: 4670506 (1987-06-01), Goldenberg et al.
patent: 5508317 (1996-04-01), Muller

Affiliated with

Also associated with

Rating

Crosslinked polymers does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Crosslinked polymers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Crosslinked polymers will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-850290