Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-05-31
2004-08-03
Peng, Kuo-Liang (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C528S038000, C526S279000, C526S301000, C526S302000, C526S328000, C525S474000, C544S071000, C524S110000
Reexamination Certificate
active
06770707
ABSTRACT:
The object of the present invention is:
radically polymerisable compositions which contain at least one monofunctional monomer with at least one difunctional monomer;
resins which are obtainable by radical copolymerisation of said compositions; it being possible for the resins to be photochromic or not;
articles, notably ophthalmic articles, which are constituted totally or in part of such resins
new monofunctional monomers.
The manufacture of a plastic ophthalmic lens is a difficult exercise insofar as it is required that the structure of said lens be free from optical constraints and obviously possesses satisfactory mechanical properties. In order to attain this result, it is necessary to perfectly master the copolymerisation reactions implemented during the preparation of said lens. It is necessary in any case to avoid attaining the gel point of the reaction system too rapidly since, in the hypothesis of “local over-cross-linking”, strings and other optical faults inexorably appear. This problem is a real problem insofar as the basic monomers known hitherto are generally symmetrical difunctional monomers.
Furthermore, within the context of the manufacture of photochromic ophthalmic lenses, either by radical polymerisation of compositions which contain at least one photochromic colorant, or by later diffusion of such colorants within the polymerised matrices, it is necessary that the structure of said lens possesses, in addition to the optical qualities set forth supra, a pronounced aptitude to favour the expression of the photochromic properties of said colorants which intervene; and this without notably altering its mechanical properties.
Obtaining an acceptable compromise—optical properties, even photochromic/mechanical properties—is not an easy thing.
Hitherto, the Applicant and his competitors are still working on the improvement of this compromise.
Photochromic transparent organic materials which have good photochromic properties are described in U.S. Pat. No. 5,973,039. They are based on a tetraethoxylated bisphenol A dimethacrylate homopolymer and contain suitable photochromic colorants. The polymerisation is carried out in the presence of a suitable radical polymerisation initiator. The optical quality of these materials does however reveal to be insufficient for ophthalmic applications.
U.S. Pat. No. 5,349,035 proposes, in order to minimise, even prevent optical constraints, to combine at least one other monomer, notably of styrene, with a dimethacrylate type monomer (and notably with that set forth supra), and to carry out the copolymerisation in the presence of an effective amount of a chain transfer agent. The matrix obtained is however not suitable for expressing the photochromic properties of photochromic colorants. Said matrix notably has fading kinetics which are much too slow.
Furthermore, in the application WO-A-98 50443, organic materials have been described which are photochromic or not, which are improved, and which are based on at least two different types of difunctional monomers.
The Applicant presently proposes using monofunctional (styrenic) monomers as comonomers in radically polymerisable compositions. Said monofunctional monomers, with suitable partners, can improve the copolymerisation in question and confer flexibility to the copolymer resulting from said copolymerisation. Copolymers of this type constitute a novel material which is very interesting, and which possesses improved optical and optionally photochromic properties.
According to its first object, the present invention thus relates to radically polymerisable compositions which contains specific radically copolymerisable monofunctional monomers. Said specific monofunctional monomers are of formula (I) below
in which:
R
1
and R
2
, which are identical or different, independently are hydrogen or an alkyl radical, which is linear or branched, advantageously linear, and comprises 1 to 4 carbon atoms; and particularly advantageously correspond to a methyl group;
R
3
and R
4
, which are different, independently are one hydrogen and the other an alkenyl radical comprising 2 to 6 carbon atoms, advantageously 2 to 4 carbon atoms, and particularly advantageously an isopropenyl radical;
Z represents a carbamate function (—NH—CO—O—), a thiocarbamate function (—NH—CO—S—), a urea function (—NH—CO—NR
7
, with R
7
which represents a hydrogen or a linear, branched or cyclic alkyl group which comprises 1 to 6 carbon atoms) or an oxazolidone function
R
5
is selected from the group comprising:
alkylene oxide radicals and polyalkylene oxide chains of formula:
in which the R groups, which are identical or different when m≧2, are alkylene radicals, which are linear or branched, and which comprise 2 to 5 carbon atoms, and m is an integer, such that the total number of carbon atoms of said alkylene oxide radicals and polyalkylene oxide chains be between 2 and 112;
ester radicals and polyester chains of formula
in which the R groups, which are identical or different when n≧2, are alkylene radicals, which are linear or branched, and which comprise 2 to 5 carbon atoms, and n is an integer, such that the total number of carbon atoms of said ester radicals and polyester chains be between 2 and 168;
siloxane radicals and polysiloxane chains of formula
in which the R′ groups and the R″ groups, which are independently identical or different when n≧2, are alkyl radicals which comprise 1 or 2 carbon atoms, and n is an integer between 1 and 18;
carbonate radicals and polycarbonate chains of formula
in which the R groups, which are identical or different when n≧2, are alkylene radicals, which are linear or branched, and which comprise 1 to 5 carbon atoms, and n is an integer between 1 and 21; and
R
6
is an alkyl radical or an aryl radical.
R
3
or R
4
, which is an alkenyl radical, advantageously an isopropenyl radical, constitutes the functional group of the (monofunctional) monomers. In formula (I), R
3
advantageously represents an isopropenyl radical (whereas R
4
represents hydrogen).
R
5
constitutes the group of said monofunctional monomers which confers flexibility to the final copolymer. R
6
is the terminal group of the chain. The nature of said terminal group is not a determining factor. It is advantageously a linear, cyclic or branched alkyl group which comprises 1 to 9 carbon atoms (preferably 1 to 4 carbon atoms) or an aryl group selected from optionally substituted phenyl and naphthyl groups. In formula (I), R
5
advantageously represents an alkylene oxide radical or a polyalkylene oxide chain. Particularly preferably, R
5
is selected from:
an ethylene oxide radical,
a polyethylene oxide chain,
a propylene oxide radical,
a polypropylene oxide chain,
a tetramethylene oxide radical, and
a polytetramethylene oxide chain.
It will obviously have been understood that for R
5
, “radical” is referred to when m or n=1 and “chain” is referred to when m and n>1.
These monofunctional monomers can be obtained without any particular difficulty by condensation of an isocyanate-bearing unsaturated compound such as 3-isopropenyl-&agr;, &agr;-dimethylbenzylisocyanate (notably marketed under the reference m-TMI® by the company CYTEC) and of an amine-, hydroxyl-, thiol-, or epoxy-bearing compound which contains a flexible group (R
5
). The reagents in question are:
firstly:
and secondly:
Some of said specific monofunctional monomers—those of formula (I) in which R
5
is selected from the group consisting in siloxane radicals, polysiloxane chains, carbonate radicals and carbonate chains—are new and constitute a further object of the present invention.
According to its first object, the present invention relates to radically polymerisable compositions which contain at least one monofunctional monomer as defined above and at least one monomer of an other type which is copolymerisable with said monofunctional monomer(s) and which is as defined below (one difunctional monomer).
The described monofunctional monomers are in fact comonomers of choice, which can improve the copolymerisat
Henry David
Lecrivain Cécile
Chen Siwen
Corning Incorporated
Peng Kuo-Liang
Schaerle Timothy M.
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