Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
1999-10-07
2002-03-19
Wilson, James O. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S223000
Reexamination Certificate
active
06359170
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to (alkyl,bromo)phenoxy alkyl(meth)acrylate monomers and polymers made therefrom.
BACKGROUND
Reactive chemical monomers can be used to prepare polymeric materials which have various properties and which are useful for various applications. As one example, monomers having optical properties can generally be used, alone or in combination with other reactive materials, to produce useful products having a high index of refraction, and that are useful to control the flow and intensity of light. To continually improve such products, or the processes for preparing such products, there is an ongoing need to develop new and improved high index of refraction monomeric materials.
Some brominated aromatic (meth)acrylate monomers have been found to be useful as high index of refraction monomers. These monomers can exhibit desirable optical qualities, but generally tend to display relatively high melting points, and therefore exist as solids at temperatures near room temperature (e.g., in the range from about 20 to 30C). Often such known brominated monomers have melting points significantly above room temperature. In addition, polymerization of these monomers (by themselves or with other comonomers) can frequently lead to a polymer with a relatively high glass transition temperature (Tg) which can limit the range of application of such monomers.
It would be desirable to identify monomers useful to produce optical materials, where the monomers have physical properties including a relatively high index of refraction, a relatively low melting point in combination with a relatively low room temperature viscosity, and which can be used to prepare polymers (e.g., homopolymers or copolymers)having a relatively low Tg.
SUMMARY OF THE INVENTION
The invention provides (alkyl,bromo)phenoxy alkyl(meth)acrylate monomers. The term (alkyl,bromo)phenoxy alkyl(meth)acrylate is used herein to refer to chemical compounds comprising a (meth)acrylate, a phenoxy ring substituted with at least bromine and an alkyl group, and a divalent alkylene group connecting the (meth)acrylate to the phenoxy ring. Preferred monomers exhibit a relatively high index of refraction; i.e., at least 1.50. Preferred monomers also have a relatively low melting temperature; i.e., below about 60 degrees celsius (60C), more preferably below about 35C or 30C, and most preferably exist as a liquid at or near normal room temperature (e.g., 25C). In addition, preferred monomers have a relatively low room temperature viscosity, and can be polymerized, either alone or in combination with one or more other comonomers, to prepare polymers with a relatively low glass transition temperature (Tg), e.g., <50C.
An aspect of the invention relates to (alkyl,bromo)phenoxy alkyl(meth)acrylate monomers such as those having the general formula:
wherein m is from 1 to 4; R2 is hydrogen or methyl, R1 is a straight or branched alkyl having at least two carbon atoms, and L is a straight or branched alkylene.
Another aspect of the invention relates to a polymerizable composition containing an (alkyl,bromo)phenoxy alkyl(meth)acrylate monomer such as that defined directly above. The polymerizable composition can further contain one or more other comonomer.
Yet another aspect of the invention relates to a polymer or polymeric material comprising a chemical segment having the formula:
wherein m is from 1 to 4, R2 is —H or methyl, R1 is a straight or branched alkyl having at least two carbons, and L is a straight or branched alkylene. Such a polymer can be prepared by polymerization of the (alkyl,bromo)phenoxy alkyl(meth)acrylate monomer.
As used within the present description, “monomer” refers to a monomer on an individual (i.e., molecular) scale, and also 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), and index of refraction).
“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 of sodium yellow light at a wavelength of about 583.9 nanometer (nm). Index of refraction can be measured by known methods, and is generally measured using an Abbe Refractometer.
“Glass transition temperature,” (Tg), is the temperature range over which a thermoplastic polymer changes from a brittle, glass state to a plastic state. Tg can be measured by methods known in the analytical chemistry art, such as the method described in the Examples section below.
“(Meth)acrylate” refers to both acrylate and methacrylate compounds.
DETAILED DESCRIPTION
Monomers of the invention include (alkyl,bromo)phenoxy alkyl(meth)acrylate monomers, wherein the alkyl group includes at least two carbon atoms (also referred to herein as “the monomer” or “the brominated monomer,” in both singular and plural forms). The (alkyl,bromo)phenoxy alkyl(meth)acrylate monomer can comprise a (meth)acrylate, a phenoxy ring substituted with substituents comprising bromine and an alkyl group, and a divalent alkylene group connecting the two.
The alkyl group can be straight or branched, and can preferably have from 2 to about 12 carbon atoms, more preferably from about 3 to about 12 carbon atoms. The size, position, and structure of the alkyl group are believed to affect properties of the monomer and polymers prepared therefrom, including the refractive index and viscosity of the monomer, and the refractive index and Tg of a polymer made from the monomer. For example, relatively larger or more branched alkyl groups can provide monomers capable of being polymerized to polymers having relatively lower glass transition temperatures, compared to otherwise similar monomers having fewer carbon atoms or less branching. Additionally, a relatively larger alkyl group can result in a monomer or polymer having a relatively lower index of refraction as compared to a similar monomer having a relatively smaller alkyl group.
The alkylene group can generally be any divalent organic hydrocarbon group. The alkylene group can be straight or branched, and preferred alkylene groups can contain from about 1 to about 12 carbon atoms, more preferably from about 2 to about 6 carbons. The size and chemical structure of the alkylene group can affect the physical properties of the monomer and a polymer prepared therefrom, including the refractive index and viscosity of the monomer and the refractive index and Tg of a polymer prepared from the monomer. A relatively larger alkylene group can result in a monomer or polymer having a relatively lower index of refraction as compared to an otherwise similar monomer having a relatively smaller alkylene group. Relatively larger or more branched alkylene groups can provide a monomer which when polymerized has a relatively lower Tg compared to a polymer prepared from otherwise similar monomers having relatively smaller or less branched alkylene groups.
Bromine substitution can affect the index of refraction of the monomer. It is generally understood that bromine increases the index of refraction of the monomer. Bromine can be substituted on the aromatic portion of the monomer in any available amount or position, and will preferably be present in an amount to provide a monomer having a relatively high index of refraction, preferably at least about 1.50. This can be accomplished, for example, by having at least two bromines directly attached to the aromatic ring.
Often, the position of the bromine can be a function of the materials and process used to prepare the brominated monomer (e.g., as described infra). Also, the position of an alkyl group on the aromatic ring can affect at least in part the position of bromines attached directly to the aromatic ring. If an alkyl group is attached at the 4 position relative to th
3M Innovative Properties Company
Fagan Lisa M.
Tucker Zachary C.
Wilson James O.
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