Hydrophilic modifier monomers

The invention relates to hydrophilic monomers and to their use for modification of oligomers, particularly oligomers used in the manufacture of contact lenses, to increase hydrophilicity of resulting polymers and increase mold compatibility in the manufacture of such molded polymers.

There is an extensive body of literature on hydrophilic monomers in the art and a large number of such monomers is commercially available. These monomers impart hydrophilicity, water absorption, and/or improve the wetting properties of materials having them copolymerized therein over the same material absent such monomers. They also result in highly hydrophilic, highly absorbent, and highly wettable homopolymeric materials. These commercial monomers can be obtained from typical monomeric suppliers such as ROHM Tech, typically under the MHOROMER®D series; Sartomer; and Alcolac, typically under the SIPOMER® series.

A general characteristic of such known modifiers is that there is a hydrophilic group and a copolymerizable group. A typical example is N-vinyl pyrrolidone; another is hydroxyethylmethacrylate. Each of these is suitable for copolymerizing with other monomers or oligomers containing one or more free (meth)acrylic or vinylic groups. The addition of the free hydroxy or the amide increases the hydrophilicity, water absorbability and wettability of the resulting polymers over those not having such monomers present.

For many utilities, it is desired that the polymeric materials resulting therefrom be in molded form. This is typical in the field of contact lenses. Also frequently, molds are poly(methyl methacrylate) and copolymerizing a) the aforementioned modifying monomers with b) the monomers or oligomers being modified in such molds results in etching and scarring of the molds. This is extremly disadvantageous for ultimate polymer utilities which require mar free surfaces, i.e. high quality optical surfaces. In these situations, molds must be replaced extremely frequently resulting in high production costs and slowed production rates.

It is therefore an object of the invention to remedy the above defects and provide a hydrophilic monomer which will substantially reduce the amount of mold etching in preparing hydrophilically modified material.

Another object of the invention is to provide hydrophilically modified polymers.

Another object of the invention is to provide contact lenses having increased wettability and/or water absorption.

A still further object of the invention is to provide a contact lens which is surface modified by a hydrophilic modifier monomer.

These and other objects can be realized by utilizing hydrophilic modifier monomers of the formula I,         (X-div)_zHy     (I) <ul id="ul0001" list-style="none"><li>wherein X is a polymerizable ethylenically unsaturated group selected from vinyl, 1-lower alkyl vinyl, 2-lower alkyl vinyl, 1,2-di(lower alkyl)vinyl and vinyl-lower alkyl,</li><li>div is a divalent group selected from alkylene of 2-6 carbons which is terminated on one side by carbonyloxy, <ul id="ul0002" list-style="none" compact="compact"><li>ca) the carbonyl being bound to X and said alkylene being interrupted once by -NH(CO)O- or</li><li>cb) terminated at the other side by -NH(CO)-, the amidocarbonyl being bound to Hy,</li></ul></li><li>and a divalent -C(O)O-aliphatic-OC(O)NH-aryl-NHC(O)O-aliphatic-group with the terminal carbonyl group being bound to X, wherein aryl is phenyl or naphthyl, unsubstituted or substituted by halogen or C_1-4 alkyl, and wherein each of the aliphatic groups is alkyl of up to 10 carbon atoms,</li><li>z is an integer of 1 up to the valence of Hy and where z is less than the valence of Hy, the remaining valences of Hy are taken up with hydrogens; and</li><li>Hy is a hydrophilic group selected from morpholino; cyclic mono amide radicals of 5-7 ring members which are selected from carbon and one nitrogen; saturated and unsaturated cyclic radicals having 5-6 ring members of the formula III, <chemistry id="chem0001" num="0001"><img file="EP0331633B1_D0001.tif" /></chemistry> wherein R^a is alkylene or alkenylene of 2 or 3 carbons, cyclic amides having 6-7 ring members of the formula IV, <chemistry id="chem0002" num="0002"><img file="EP0331633B1_D0002.tif" /></chemistry> wherein q and r are each independently 0-2, cyclic amines of the formula <chemistry id="chem0003" num="0003"><img file="EP0331633B1_D0003.tif" /></chemistry> wherein R^a is alkylene or alkenylene of 2 or 3 carbons; each of which is unsubstituted or substituted by hydroxy -C_1-5 alkyl, carboxy, or lower alkyl; a divalent group of formula XVa <chemistry id="chem0004" num="0004"><img file="EP0331633B1_D0004.tif" /></chemistry> wherein R¹⁰ is hydrogen or carboxy, and <chemistry id="chem0005" num="0005"><img file="EP0331633B1_D0005.tif" /></chemistry> which is substituted by one hydroxy.</li><li>X is preferably vinyl, 1- or 2-lower alkyl vinyl, more preferably 1-methyl vinyl, or 2-methyl vinyl, or allyl.</li></ul>

Preferably Hy is selected from <ul id="ul0003" list-style="none" compact="compact"><li>ba) morpholino which is unsubstituted or mono- up to tetra-substituted by lower alkyl, preferably methyl or ethyl;</li><li>bb) an amide of the formula XII <chemistry id="chem0006" num="0006"><img file="EP0331633B1_D0006.tif" /></chemistry> wherein d is 1-3, preferably 1; each of which is unsubstituted or substituted, preferably mono or di substituted, by lower alkyl, preferably methyl or ethyl;</li><li>bc) a group of formula XIII, <chemistry id="chem0007" num="0007"><img file="EP0331633B1_D0007.tif" /></chemistry> wherein e is 2-3, preferably 2, each of which is unsubstituted or substituted by lower alkyl, preferably methyl or ethyl;</li><li>bd) a divalent group of one of the formulae XIV, XV, XVa, XVI, XVIIa or XVIIb, <chemistry id="chem0008" num="0008"><img file="EP0331633B1_D0008.tif" /></chemistry><chemistry id="chem0009" num="0009"><img file="EP0331633B1_D0009.tif" /></chemistry> wherein R¹⁰ is hydrogen or carboxy;</li><li>be) <chemistry id="chem0010" num="0010"><img file="EP0331633B1_D0010.tif" /></chemistry></li><li>bf) <chemistry id="chem0011" num="0011"><img file="EP0331633B1_D0011.tif" /></chemistry> wherein f is one or two, each of which is unsubstituted or substituted by lower alkyl, preferably methyl or ethyl;</li><li>bg) <chemistry id="chem0012" num="0012"><img file="EP0331633B1_D0012.tif" /></chemistry></li></ul>

Preferably div is selected from         -CO-O-(CH₂)₂NHCOO(CH₂)₂-; <chemistry id="chem0013" num="0013"><img file="EP0331633B1_D0013.tif" /></chemistry> and         -CO-O-(CH₂)₂NHCO-; in which in each case the left hand bond being bound to X.

Hy is most preferably pyrrolid-5-one-1-yl or morpholin-1-yl.

The alkylene of div is most preferably of 2 to 4 carbon atoms.

In the group div, aryl substituted by C_1-4 alkyl is most preferably substituted by methyl. In the group div, each of the aliphatic groups is more preferably an alkylene of up to 5 carbon atoms. Most preferably such aliphatic groups are -CH₂C₂-.

Most preferred are the monomers of formula I wherein X is vinyl or 1-methyl vinyl; z is one; <ul id="ul0004" list-style="none" compact="compact"><li>div is selected from -C(O)O-C_2-6-alkyl- which is interrupted once by -NHC(O)O- within the alkyl portion, the terminal carbonyl group being bound to X;</li><li>-C(O)O-C_2-6-alkyl-NHCO-, the terminal carbonyl group of the oxycarbonyl portion being bound to X; and -C(O)O-C_2-6-alkyl- which is interrupted once by -OCONH-aryl-NHCOO- in the alkyl portion, the terminal carbonyl group of which is bound to X; wherein aryl is phenyl or phenyl substituted by C_1-4-alkyl, preferably methyl;</li><li>and Hy is pyrrolidon-5-one-1-yl or morpholin-1-yl.</li></ul>

The most highly preferred monomers of the invention are of formula XIX, XX and XXIV: <chemistry id="chem0014" num="0014"><img file="EP0331633B1_D0014.tif" /></chemistry><chemistry id="chem0015" num="0015"><img file="EP0331633B1_D0015.tif" /></chemistry> and <chemistry id="chem0016" num="0016"><img file="EP0331633B1_D0016.tif" /></chemistry>

The hydrophilic modifying monomers of the invention can be made in a number of ways, the individual steps of which are known in the art. The starting materials are all well known to those in the art and most are commercially available.

One set of starting materials is X-E, W-L-Y, and G-Hy wherein E is coreactive with W, and Y is coreactive with G. When the reactions of E with W and Y with G are complete, the group -EW-L-YG- is -div-. The group -L- can be a simple aliphatic hydrocarbon chain without any substituents or interruptions or terminating groups. Alternatively, it can be a complex group having a number of interrupting and/or terminating groups as well as substituents.

For example, toluene diisocyanate can represent a simple W-L-Y compound. Reaction of 1 mole thereof with 1 mole of N-hydroxyethyl pyrrolidone (an G-Hy compound) yields a compound of the formula <chemistry id="chem0017" num="0017"><img file="EP0331633B1_D0017.tif" /></chemistry>

This can then be reacted with 1 mole of 2-hydroxyethylmethacrylate (an X-E compound) to yield the compound of formula XX.

The sequence of reactions can, of course be reversed so that the X-E compound and the W-L-Y compound are first reacted and then a G-Hy compound is reacted with the result. Of course, when G is not reactive with E or X and E is not reactive with G or Hy all three components can be added together simultaneously.

The compound of formula XIX can likewise be prepared from isocyanatoethylmethacrylate (IEM) and 2-hydroxyethyl pyrrolidone.

As one of ordinary skill can appreciate, replacing the N-(2-hydroxyethyl)-pyrrolidone with a N-(2-hydroxyethyl)morpholine yields the product shown in formula XXIV. Synthetic routes to the rest of the monomers within the invention are within the ability of one of ordinary skill in this art.

Based on the foregoing, the following examples are presented to illustrate, but not limit the invention.

<u>Example 1</u>: To a clean, dry 100 ml round bottom flask equipped with condenser, nitrogen inlet and thermomether are added 15.53 g, 0.10 moles isocyanatoethyl methacrylate, 0.02 g dibutyl tin dilaurate and 50 ml methylene chloride. The mixture is stirred under a nitrogen atmosphere to effect solution. To the solution is added 12.93 g, 0.10 moles hydroxyethyl pyrrolidone. After 1.5 hours the isocyanate band is not observed in the FT infrared spectrum. The solvent is removed via stirring under a dry-air purge.

<u>Example 2:</u> The above modifier of Example 1 is added to <ul id="ul0005" list-style="none" compact="compact"><li>a) styrene isocyanate endcapped polypropylene glycol 4000,</li><li>b) the monomers of formula V of US-A-4,780,488, filed June 5, 1987, or</li><li>c) the monomers of formula I of US-A-4,740,533, filed July 28, 1987</li></ul> in amounts of 10 % or 15% by weight and cured. The resulting polymers all have increased water content over the corresponding polymer without the compound of example 1 present.