Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2001-05-01
2004-11-02
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S035000, C528S275000, C528S288000, C528S300000, C528S301000, C528S370000, C528S371000, C528S392000, C524S081000, C524S777000
Reexamination Certificate
active
06812265
ABSTRACT:
The present invention relates to a liquid composition polymerizable into organic glasses.
More specifically, the present invention relates to a liquid composition which can be polymerized, by means of radical polymerization with low shrinkage, into organic glasses having good optical and physico-mechanical properties, comprising the product obtained from the transesterification of a diallyl carbonate (A) with a mixture of one or more diols (3) with a polyol (C).
A further object of the present invention relates to the organic glasses obtained from the polymerization of said composition.
Finally, the present invention also relates to the end-articles obtained starting from said composition, such as for example, ophthalmic lenses and solar filters, protective shields, sight windows, solar and photovoltaic collectors and panels, substrates for optical disks, panels for display and video terminals.
In the field of high transparency organic glasses, the product obtained from the polymerization of diethylene glycol bis(allyl carbonate) is of great commercial interest in the production of ophthalmic and safety plates and lenses, owing to its special mechanical and age-resistance characteristics, as described, for example, by F. Strain, in: “Encyclopedia of Chemical Processing and Design”, First Edition, Dekker Inc., New York, Vol. 11, page 452 onwards; and in “Encyclopedia of Polymer Science and Technology” (196.4), Vol. 1, page 799 onwards, Interscience Publishers, New York.
The use of diethylene glycol bis(allyl carbonate), however, has various disadvantages which limit and, at times, prevent its use in different fields of application.
For example, the shrinkage which accompanies the polymerization reaction of bis (allyl carbonate) in the presence of peroxide initiators, makes the preparation of high power lenses difficult. The abrasion resistance of the organic glasses thus obtained, although much higher than that of other known organic glasses, still cannot be considered as being optimum: this is demonstrated by the fact that it is customary to resort to the surface application of scratch-proof coatings on this organic glass.
Not even the impact strength of the above organic glasses, although its value is sufficient to pass the tests imposed by the regulations in force in the optical field, can be considered as being optimum.
Numerous compositions polymerizable into organic glasses have been described in an effort to overcome these drawbacks and to improve some of the most important characteristics of organic glasses.
For example, the patent U.S. Pat. No. 4,812,545, discloses liquid compositions polymerizable into organic glasses comprising tris(hydroxyethyl)isocyanurate tris(allyl carbonate); and diethylene glycol bis(allyl carbonate) monomeric and oligomeric, having an improved shrinkage during polymerization and a better impact strength.
The patent U.S. Pat. No. 4,713,433 on the other hand, describes liquid compositions polymerizable into organic glasses comprising oligomeric bis(allyl carbonate) and a comonomer having at least four terminal allyl groups capable of producing organic glasses with an improved abrasion resistance.
Finally, the patent U.S. Pat. No. 4,970,293 discloses liquid compositions polymerizable into organic glasses comprising the reaction product of a diallyl carbonate with mixtures of a diol and a polyol containing from three to six hydroxyl groups per molecule. However, although these compositions on the one hand effectively represent an improvement in some specific characteristics of the organic glasses obtained from their polymerization, on the other hand, !they have other characteristics which are worse than those of the organic glasses obtained from the polymerization of diethylene glycol bis(allyl carbonate) alone.
As already mentioned above, the organic glass obtained from the polymerization of diethylene glycol bis(allyl carbonate) alone has various disadvantages: for example, it often has yellow index values higher than those normally acceptable, and/or unacceptable refraction index values, and/or impact strenght values, and/or dyeability values. As a result, diethylene glycol bis(allyl carbonate) cannot be used alone but, as specified above, must be mixed with other comonomers which, however, have other drawbacks.
In this respect, it should be remembered that the organic glass obtained as described in the patent U.S. Pat. No. 4,970,293 mentioned above, is particularly useful in protective shields (for example, for welders), in sight windows (for example, in blast furnaces), in windows in the transport and civil industry, in lenses for vehicle lights, in solar and photovoltaic collectors and panels, in substrates for optical disks and in panels for display, but it cannot be used for optical lenses as it has a high yellow index, a low impact strenght, a poor dyeability.
The Applicant has now found a liquid composition which can be, easily polymerized by means of radical polymerization with low shrinkage, into organic glasses having good optical and physico-mechanical properties, capable of overcoming the drawbacks of the known art described above.
The present invention therefore relates to a liquid composition which can be polymerized by means of radical polymerization with low shrinkage, into organic glasses, comprising the product obtained from the transesterification of a diallyl carbonate (A) with a mixture of one or more linear or branched aliphatic diols (B), containing from three to ten carbon atoms in the molecule with a linear or branched aliphatic polyol (C), containing from four to twenty carbon atoms and from three to six hydroxyl groups in the molecule, wherein the molar ratio (A)/(B+C) ranges from 2.5/1 to 4/1, and the quantity of (C) in the mixture (B+C) ranges from 5% by weight to 20% by weight with respect to the total weight of the mixture (B+C).
Diols (B) which can be used for the purposes of the present invention, as already mentioned above, are linear or branched aliphatic diols, containing from three to ten carbon-atoms in the molecule.
Specific examples of diols (B) which can be used for the purposes of the present invention are: diethylene glycol, triethylene glycol, tetraethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,3-propanediol, neopentylglycol, dipropyleneglycol, 2,2,4-trimethyl-1,3-pentanediol, etc.
Preferred diols for the purposes of the present invention are diethylene glycol and neopentylglycol.
Polyols (C) which can be used for the purposes of the present invention, as already mentioned above, are linear or branched aliphatic polyols, containing from four to twenty carbon atoms and from three to six hydroxyl groups in the molecule.
Specific examples of polyols (C) which can be used for the purposes of the present invention are: pentaerythritol, trimethylolpropane, dipentaerythritol, ditrimethylolpropane, tris(hydroxyethyl)isocyanurate, etc.
Preferred polyols for the purposes of the present invention are pentaerythritol and trimethylolpropane.
The polymerizable liquid composition of the present invention is obtained starting from diallyl carbonate (A) and the mixture (B+C) operating under transesterification conditions. More specifically, the reagents are put in contact with each other, in the ratios indicated above, and reacted at a temperature ranging from 80° C. to 160° C., preferably from 90° C. to 130° C., in the presence of a catalyst of the alkaline type, continuously eliminating the allyl alcohol formed as reaction by-product.
Catalysts of the alkaline type which can be used for the purposes of the present invention are: hydroxides, carbonates and alcoholates of alkaline metals, organic bases, basic ion-exchange resins.
Specific examples of catalysts of the alkaline type used for the purposes of the present invention are: sodium hydroxide, sodium carbonate, sodium methylate.
The catalyst is conveniently used in a quantity equal to at least 1 ppm (parts per million by weight) with respect to the sum of the weights of components (B+C) and, preferably, in a quantity ranging fr
Bendandi Andrea
Forestieri Roberto
Nodari Nereo
Renzi Fiorenzo
Acquah Samuel A.
Ferrell Michael W.
Great Lakes Chemical (Europe) GmbH
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