Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1997-05-09
2002-03-12
Henderson, Christopher (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S292500
Reexamination Certificate
active
06355754
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to polymerizable compositions containing high index of refraction monomers, and polymeric materials prepared therefrom.
BACKGROUND
Optical materials and optical products can be prepared from high index of refraction materials such as polymerizable, high index of refraction monomers and curable compositions containing such high index of refraction monomers. An example of useful high index of refraction monomers are bromine-substituted aromatic (meth)acrylate monomers. See for example U.S. Pat. No. 4,578,445. Such monomers can typically be relatively high melting materials that exist in the form of a solid at or around room temperature, and often have melting points significantly above room temperature. Because these monomers exist as solids at room temperature, curable compositions containing these monomers must either be dissolved into solution, or heated to their melting points (above room temperature) to be processed and formed into a high index of refraction optical product.
The need to heat high index of refraction materials during processing adds significant complication and expense to the processing of the material into an optical product. Processing lines must be heated, which can require large amounts of energy, can sometimes rupture tubing connections, and can even cause the evolution of volatile organic compounds, thereby potentially creating a hazardous work environment. If complete and uniform heating is not consistently maintained, the monomer can crystallize within the curable composition during processing, resulting in the production of non-uniform and unusable product, and resulting in high amounts of waste product. And, maintaining the polymerizable composition at an appropriate processing temperature can potentially cause prepolymerization of the monomeric composition. Of course, all of these added process requirements and negative consequences increase the cost of producing high index of refraction products from curable compositions that exist as solids at room temperature.
It would be advantageous to identify a polymerizable composition useful to produce optical materials and optical products having a relatively high index of refraction, and a relatively low melting point, e.g., a polymerizable composition that can be processed as a liquid at temperatures equal to or near normal room temperature.
SUMMARY OF THE INVENTION
In a general sense, the present invention provides polymerizable compositions having a high index of refraction, and preferably, high index of refraction polymerizable compositions that can be processed at temperatures at or near room temperature (e.g., in the range from about 20 to 25° C.) to produce a polymer or polymeric material. The polymerizable composition contains brominated, high index of refraction monomers. The monomer and the composition can each have relatively low melting points, and desirable optical properties.
Monomers useful in the composition include alkyl-substituted brominated phenolic (meth)acrylate monomers that have relatively high indexes of refraction, and that can preferably be liquid at temperatures between near room temperature and 60° C. Even those brominated monomers that are solids in this temperature range can be desired because these can often be easily dissolved in liquid polymerizable compositions of the present invention without significantly raising the melting point of the polymerizable composition. Thus, a polymerizable composition containing these monomers can preferably have a relatively low melting point, and can more preferably exist in the form of a liquid at temperatures at or around room temperature, thereby reducing or eliminating the need to heat these compositions during processing. The invention thereby eliminates expense and complication otherwise associated with heating a polymerizable composition to prepare high index of refraction polymeric materials. By “processing,” it is meant that the monomer or polymerizable composition can be blended, pumped, or otherwise handled prior to polymerization and manufacturing to produce a polymer or optical product.
An aspect of the invention relates to a polymerizable composition containing an alkyl-substituted brominated aromatic ester (meth)acrylate monomer, the brominated monomer preferably having an index of refraction of at least 1.50. The polymerizable composition further contains one or more comonomer or comonomers, including at least one high index of refraction comonomer.
Yet another aspect of the invention relates to polymer or polymeric material comprising monomeric units derived from the above-described polymerizable composition. Specifically, the invention relates to a polymer or polymeric material derived from ingredients including an alkyl-substituted brominated aromatic ester (meth)acrylate monomer, the brominated monomer preferably having an index of refraction of at least 1.50, and one or more comonomer or comonomers, including at least one high index of refraction comonomer.
As used within the present description.
“Monomer” refers to a monomer on an individual scale, and also refers collectively to a composition of such monomers on a macroscopic scale such that the composition can be described as having a physical state of matter (e.g., liquid, solid, etc.) and physical properties (e.g., melting point, viscosity, glass transition temperature (of a polymeric form of the monomer), or refractive index).
“Melting point,” as used with respect to the monomer, refers to the temperature at which the monomer passes from a solid to a liquid state, as measured at atmospheric pressure. Melting point can be measured, for example, using a Thomas-Hoover Melting Point Apparatus, from Thomas Scientific of Swedesboro N.J.
“Index of refraction,” or “refractive index,” refers to the absolute refractive index of a material (e.g., a monomer) which is understood to be the ratio of the speed of electromagnetic radiation in free space to the speed of the radiation in that material, with the radiation being sodium yellow light at a wavelength of about 583.9 nm. Index of refraction can be measured using an Abbe Refractometer.
(Meth)acrylate refers to both acrylate and methacrylate compounds.
DETAILED DESCRIPTION
The present invention describes a polymerizable composition comprising an alkyl-substituted brominated phenolic ester (meth)acrylate monomer. As used within the present description the term “polymerizable” refers to a chemical molecule such as a monomer or oligomer, etc., or a chemical composition, capable of polymerizing or copolymerizing (e.g., via unsaturated moieties) to produce a higher molecular weight material such as a polymer or polymeric material. “Polymer” or “polymeric material” are used interchangeably to refer to materials prepared from the reaction of one or more unsaturated materials, e.g., one or more monomer, oligomer, or polymer, prepolymer, etc., and includes, e.g., dimers, trimers, oligomers, pre-polymers, copolymers, homopolymers, etc.
The alkyl-substituted brominated aromatic ester (meth)acrylate monomer, also preferred to herein as “the Monomer,” or the “Brominated Monomer,” preferably has physical properties that allow processing of the composition at or near room temperature to produce a high index of refraction optical product. Thus, the Brominated Monomer has a relatively high index of refraction, and preferably has a relatively low melting point.
The substituents of the aromatic portion of the Monomer can affect or substantially determine the physical properties of the Monomer, including index of refraction and melting point. These properties are believed to be affected by the chemical composition of the substituents, the size and number of such substituents, and the location of such substituents on the monomeric structure, e.g., on the aromatic portion of the Monomer. While wishing not to be bound by theory, the alkyl substituent (e.g., its size, position, and chemical composition) is believed to affect the melting point of the Monomer. Further, the position of the alkyl group
Fong Bettie C.
Olson David B.
3M Innovative Properties Company
Black Bruce E.
Henderson Christopher
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