Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
1999-10-15
2002-03-26
Zitomer, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C525S326500, C526S279000, C528S014000, C528S015000, C528S019000, C528S021000, C528S023000
Reexamination Certificate
active
06362301
ABSTRACT:
The present invention relates to curable compositions. In particular, this invention relates to a curable composition including an alkoxysilane containing oligomer and a catalyst, a second curable composition including an alkoxysilane containing oligomer and a photocatalyst, and methods of forming cured films.
Polymeric materials are used extensively as films and coatings to protect and to improve the appearance of substrates. To enhance the durability, toughness, and barrier properties of the films and coatings, the polymeric materials are often crosslinked, using a variety of cure chemistries. One such crosslinking chemistry is the condensation reaction of alkoxysilanes. Polymers with alkoxysilane groups, usually in the presence of catalyst, are reactive with moisture and can form crosslinked polymer films at ambient temperatures.
U.S. Pat. No. 4,499,150 teaches a method for coating substrates wherein the coating composition contains an addition interpolymer having alkoxysilane and/or acyloxysilane groups. The crosslinkable interpolymer is formed by the polymerization of alkoxysilane monomers and/or acyloxysilane monomers with other silicon-free monomers. The interpolymer is polymerized in an organic solvent by a batch process at 119° C. and uses initiators and chain transfer agents to achieve a desired molecular weight in the range of 2,000 to 20,000.
It is known in the art that high temperature processes are effective at producing low molecular oligomers from ethylenically unsaturated monomers. At high temperatures, depolymerization reactions and chain fragmentation processes compete with the polymerization reactions which grow the polymer chain length. For example, U.S. Pat. No. 5,710,227 teaches a high temperature polymerization of acrylic monomers above 150° C. by a continuous process to produce acrylic acid homo-oligomers and co-oligomers. One advantage of a high temperature process is the ability to eliminate the chain transfer agents which are often needed to control the molecular weight of the oligomers produced by lower temperature processes. Drawbacks to the use of chain transfer agents are that they add to the cost of the process, impart unneeded-functionality to the polymer, may introduce salts into the product, or necessitate a product separation step. Also, the mercaptan chain transfer agents commonly employed are not only expensive but require special handling since they are extremely odoriferous. A second advantage is that high temperature polymerization conditions can be readily adapted to a continuous process to obtain high production rates of oligomers.
A curable composition incorporating an oligomer containing alkoxysilane groups wherein the oligomer has been produced by a facile and economical process has long been sought.
In the present invention, a curable composition is provided including a alkoxysilane or acyloxysilane oligomer formed by a continuous reaction process at 150° C. to 500° C. The high temperature reaction continuous process produces alkoxysilane oligomers with degrees of polymerization ranging from 2 to 100 preferably without the use of chain transfer agents and with low levels of initiators. In an alternate embodiment of this invention, the alkoxysilane oligomer may be produced by the high temperature process without the use of solvents. A curable composition containing an alkoxysilane oligomer and a photoinitiator is also provided whereby the cure is initiated by exposure to actinic radiation.
In the first aspect of this invention, there is provided a curable composition including:
(A) an oligomer prepared by a continuous process from one or more monomers selected from the group consisting of ethylenically unsaturated alkoxysilanes and acyloxysilanes, and optionally, one or more other ethylenically unsaturated monomers, wherein the monomers are polymerized at a temperature of 150° C. to 500° C., wherein the oligomer has a degree of polymerization from 2 to 100; and (B) a catalyst.
In a second aspect of the present invention, there is provided a method of forming a film incorporating the curable composition of the first aspect.
In the third aspect of the present invention, there is provided a curable composition comprising:
(A) an oligomer comprising moieties selected from the group consisting of alkoxysilane and acyloxysilane moieties wherein the oligomer is prepared from the polymerization of ethylenically unsaturated monomers, wherein the oligomer has a degree of polymerization from 2 to 100; and
(B) a photoinitiator.
In a fourth aspect of the present invention, there is provided a method of forming a film incorporating the curable composition of the third aspect.
As used herein, the term “acrylate” refers to esters of acrylic acid and the term “methacrylate” refers to esters of methacrylic acid. As used herein, the term “substantially free” means less than 0.5% by weight. As used herein, the term “oligomer” refers to a polymer prepared from ethylenically unsaturated monomers with a degree of polymerization in the range of 2 to 100.
The curable compositions of the present invention are believed to cure by covalent bond formation through reactions between the alkoxysilane containing oligomers. In the presence of a catalyst, the alkoxysilane groups can undergo condensation reactions leading to bond formation between oligomer chains and an increase in the molecular weight of the composition. The curing can be as simple as the formation of a single Si—O—Si between two different oligomer chains or can be as extensive as the formation of a network of Si—O—Si crosslinks throughout the curable composition.
The oligomer component of the curable composition is an alkoxysilane containing polymer. The oligomers are prepared by polymerizing ethylenically unsaturated alkoxysilane, acyloxysilane monomers or mixtures of these monomers to form oligomers or with other monomers to obtain co-oligomers. The choice of monomers is dependent on many factors including the intended end use of the curable composition, viscosity of the curable composition, and the monomer costs. Suitable alkoxysilane and acyloxysilane monomers include, for example, vinyl alkoxysilanes, allyl alkoxysilanes, acryloxyalkyl alkoxysilanes, methacryloxyalkyl alkoxysilanes, vinyl acyloxysilanes. Preferred vinyl alkoxysilane monomers are vinyl trialkoxysilanes, vinyl monoalkyldialkoxysilanes, and vinyl dialkylmonoalkoxysilanes wherein the alkyl group contains 1 to 6 carbons and the alkoxy group contains 1 to 6 carbons.
Examples of preferred alkoxysilane and acyloxysilane monomers include vinyl trimethoxysilane, vinyl triethoxysilane, vinyl triisopropoxysilane, vinyl triacetoxysilane, vinyl methyldimethoxysilane, vinyl dimethylethoxysilane, allyl trimethoxysilane, 3-acryloxypropyl trimethoxysilane, 3-acryloxypropyl methyldimethoxysilane, methacryloxymethyl triethoxysilane, methacryloxypropyl methyldiethoxysilane, and methacryloxymethyl ris(trimethylsiloxy)silane.
Optional ethylenically unsaturated monomers suitable for copolymerization with the ethylenically unsaturated alkoxysilane and acetoxysilane monomers are esters of acrylates, esters of methacrylates, amides of acrylates, amides of methacrylates, vinyl aromatics, and vinyl esters of carboxylic acids. Examples of ethylenically unsaturated monomers include methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, N,N-dimethylaminopropyl methacrylamide, vinyl acetate, and styrene. Preferred monomers are ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, vinyl acetate, and methyl acrylate.
As used herein, the term “co-oligomer” is defined as an oligomer containing an alkoxysilane or acyloxysilane monomer and at least one other monomer. The monomer units of the co-oligomer may be arranged to form alternating, random, or block polymer structures. Oligomers formed from more than two different types of monomers, such as terpolymers or “ter-oligomers” are also contemplated. In the broadest sense, it is understood that in an oligomer with a degree
Bowe Michael Damian
Graham Linda Louise
Greenblatt Gary David
Lange Barry Clifford
Merritt Richard Foster
Bakule Ronald D.
Rohm and Haas Company
Zitomer Fred
LandOfFree
Curable composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Curable composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Curable composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2883781