Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
2000-11-06
2003-04-29
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S090000, C522S096000, C522S150000, C522S151000, C522S173000, C522S174000, C526S301000, C526S302000, C526S310000
Reexamination Certificate
active
06555596
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to multifunctional allyl carbamates. More particularly, the invention relates to multifunctional allyl carbamates that are useful for air-drying and UV-curable coatings.
BACKGROUND OF THE INVENTION
Allyl monomers hardly homopolymerize but readily copolymerize with vinyl and acrylate monomers. They are strong chain transfer agents and give the copolymers low molecular weights. This unique characteristic has led to the development of a variety of copolymers of allyl alcohol or alkoxylated allyl alcohols with vinyl aromatics (see, e.g., U.S. Pat. No. 5,451,631) and acrylates (see, e.g., U.S. Pat. No. 5,525,693). These copolymers are characterized by an even distribution of hydroxyl groups. See S. Guo,
Solvent Free Polymerization and Process,
ACS series book, 713, Chapter 7, pp.113-126 (1998).
More recently, copolymers of allyl carbamates with vinyl aromatics and acrylates have been disclosed. See U.S. Pat. No. 6,075,108. The '108 patent teaches monofunctional allyl carbamates, i.e., the monomers have only one allyl functional group per molecule. The copolymers are thermoplastic resins with pendant carbamate functional groups. The carbamate groups can then react with crosslinking agents such as melamine resins to form thermoset coatings.
Multifunctional acrylate carbamates are also known. (See, e.g., U.S. Pat. No. 4,126,747.) These multifunctional monomers are crosslinked through the acrylate groups by photooxidation or a free-radical reaction. Introducing carbamate groups into coatings can potentially enhance acid etch resistance, adhesion, durability, and other performance features. (See, e.g., U.S. Pat. Nos. 5,356,669 and 5,709,950).
Multifunctional allyl carbamates are of interest because they improve crosslink density and coating performance. Importantly, these monomers should give derivative coatings uniform network structures.
SUMMARY OF THE INVENTION
The invention relates to allyl carbamates. The allyl carbamates are reaction products of an isocyanate and an allylic alcohol or alkoxylated allylic alcohol. The isocyanates are selected from hexamethylene diisocyanate (HDI), HDI biuret, HDI dimer, HDI trimer, HDI allophanate, isophorone diisocyanate (IPDI), IPDI trimer, IPDI allophanate, bis(isocyanatocyclohexyl)methane, and the like, and mixtures thereof.
The invention includes air-drying and UV (ultraviolet light)-curable coatings that comprise the allyl carbamates. The invention further includes UV-curable powder coatings that comprise solid allyl carbamates and solvent-free air-drying and UV-curable coatings that comprise liquid allyl carbamates. The coatings have excellent chemical resistance and weathering stability.
DETAILED DESCRIPTION OF THE INVENTION
The allyl carbamates of the invention are prepared by reacting an isocyanate with an allylic alcohol or alkoxylated allylic alcohol. The isocyanates are selected from hexamethylene diisocyanate (HDI), HDI biuret, HDI dimer, HDI trimer, HDI allophanate, isophorone diisocyanate (IPDI), IPDI trimer, IPDI allophanate, bis(isocyanatocyclohexyl)methane, and the like, and mixtures thereof. These isocyanates are commercially available, for example, from Lyondell Chemical Company.
Methods for preparing HDI and IPDI allophanates are known. For example, U.S. Pat. No. 5,461,135, the teachings of which are incorporated herein by reference, teaches the preparation of allophanates. In one method, HDI allophanate is prepared by: (1) dimerizing HDI in the presence of tributyl phosphine to convert about 10% of the HDI to uretidione oligomers, (2) adding a suitable amount of diethylene glycol to the mixture to reach about 20 wt % of uretidione content, and then (3) adding an equivalent amount of methyl tosylate to terminate the reaction. Suitable HDI and IPDI allophanates preferably have an NCO functionality from 2.8 to 6.5, an NCO content from 10 to 47 wt %, a viscosity less than 1000 cps at 25° C., and a molar ratio of uretidione to allophanate from about 20:1 to about 1:5.
Allylic alcohols for use in the invention have the general structure:
in which R is hydrogen, C
1
to C
10
alkyl, or C
6
to C
10
aryl or alkylaryl. Suitable allylic alcohols include, for example, allyl alcohol, methallyl alcohol, 2-ethyl-2-propen-1-ol, 2-pentyl-2-propen-1-ol, and the like, and mixtures thereof.
Suitable alkoxylated allylic alcohols have the structure:
in which A is a C
2
-C
4
oxyalkylene group, and n, which is the average number of oxyalkylene units in the alkoxylated allylic alcohol, has a value within the range of 1 to about 5; preferably n is 1 to about 2. Suitable alkoxylated allylic alcohols include propoxylated allylic alcohols, ethoxylated allylic alcohols, butoxylated allylic alcohols, and the like, and mixtures thereof. Suitable alkoxylated allylic alcohols also include those having a mixture of oxyalkylene units such as oxypropylene, oxyethylene and oxybutylene. Suitable alkoxylated allylic alcohols can be made, for example, by reacting an allylic alcohol with an alkylene oxide. For example, U.S. Pat. Nos. 3,268,561 and 4,618,703, the teachings of which are incorporated herein by reference, teach how to make propoxylated allylic alcohol.
The reaction of the isocyanate with the allylic alcohol or alkoxylated allylic alcohol is preferably performed at an elevated temperature. The reaction temperature is preferably within the range of 60° C. to 160° C. A catalyst can be used to shorten reaction time, to lower the reaction temperature, or both. Suitable catalysts include tertiary amine and organotin compounds. Examples of organotin catalysts are stannous octoate and dibutyltin dilaurate. The catalyst is used in an amount less than 1 wt % of the total product. A solvent can also be used to control the reaction or lower the viscosity of the reaction mixture. Suitable solvents include ethers, esters, ketones, aromatic and aliphatic hydrocarbons, glycol ether esters, and the like, and mixtures thereof. Excess allylic alcohol or alkoxylated allylic alcohol is used to convert essentially all of the isocyanate (NCO) groups to carbamates. The small excess of allylic compounds can be removed after the reaction although they typically do not interfere with coating properties. Conversion of the NCO group to a carbamate group can be monitored by infrared spectroscopy (IR). The allyl carbamate products have an average allyl functionality of at least 2.
The invention includes UV-curable coatings that comprise the allyl carbamates. The allyl carbamates can be used as crosslinking agents in amounts preferably less than about 10 wt % of the total coating composition or as primary components in amounts preferably greater than about 10 wt % of the total coating composition.
The UV-curable coating preferably comprises a UV-curable monomer or oligomer that is capable of copolymerizing with the allyl carbamate. Examples of suitable monomers are decyl acrylate, ethoxyethyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexylvinyl ether, hexyl acrylate, isodecyl acrylate, isooctyl acrylate, isobornyl acrylate, lauryl acrylate, lauryl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, stearylacrylate, N-vinylcaprolactam, and the like, and mixtures thereof.
Examples of suitable oligomers are polyethylene glycol acrylate or methacrylate, polypropylene glycol acrylate or methacrylate, polyester acrylates or methacrylates, urethane acrylates or methacrylates, epoxy acrylates or methacrylates, and the like, and mixtures thereof.
Suitable UV-curable monomers or oligomers also include those having two or more UV-curable functional groups capable of copolymerizing with the allyl carbamates. Examples are polyethylene glycol diacrylate or dimethacrylate, 1,6-hexanediol divinylether, pentaerythritol triacrylate, ethoxylated bisphenol-A diacrylate, tripropyleneglycol diacrylate, unsaturated polyesters such as those prepared from maleic anhydride, fumaric acid, or itaconic acid or anhydride, and the like, and mixture thereof. The UV-curable monomers or oligomers are used in amounts preferably from about 50 wt % to about 95 wt % of
Goldstein Stephen L.
Harris Stephen H.
Pourreau Daniel B.
Whitman Peter J.
Arco Chemical Technology L.P.
Guo Shao
McClendon Sanza L.
Seidleck James J.
LandOfFree
Multifunctional allyl carbamates and coatings therefrom does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multifunctional allyl carbamates and coatings therefrom, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multifunctional allyl carbamates and coatings therefrom will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3034524