Combustion – Candle – e.g. – taper – etc.
Reexamination Certificate
2001-06-04
2003-02-11
Hampton-Hightower, P. (Department: 1711)
Combustion
Candle, e.g., taper, etc.
C431S289000, C431S291000, C528S170000, C528S295500, C528S296000, C528S310000, C528S322000, C528S332000, C528S339000, C528S339500, C528S343000, C528S345000, C044S265000, C044S253000, C044S459000, C522S164000, C522S175000, C427S447000, C427S487000, C427S496000
Reexamination Certificate
active
06517343
ABSTRACT:
TECHNICAL FIELD
The invention relates to candles and in particular to candles having a cured coating, and methods for their preparation.
BACKGROUND OF THE INVENTION
Candlemaking is an ancient art that continues to see improvements, driven largely by the basic aesthetic appeal of candles to the general public. A very common type of candle consists of a wick embedded in a block of paraffin wax, where the wax provides the fuel for the burning candle. Paraffin is an inexpensive raw material, which makes it an economically attractive ingredient for a candle. Paraffin is a convenient material to mold into various shapes, and accepts coloration so a wide variety of colorful and variously shaped candles can be made from paraffin. A fundamental property of paraffin is its opaqueness. Opaqueness is disadvantageous in that any visually interesting objects placed within a paraffin candle are essentially invisible, unless those objects are placed very near the surface of the candle. Also, while paraffin is generally considered comfortable to touch, it can undesirably rub off onto skin.
A modern variation on candlemaking is the use of gelled fuel in place of paraffin. Some gelled fuels have the advantage of being clear or transparent so that decorative items that are placed within a transparent candle are visible to the consumer. This transparency adds an extra dimension to candlemaking and candle design, in that it allows the creation of many interesting and commercially desirable candles. Typically, a gelled fuel is made by combining a gellant and a solvent that is gelled by the gellant. In some instances, the gelled fuel will display undesirable syneresis, which refers to a physical separation of the gellant from the fuel. Syneresis causes a gelled fuel to have a very oily feel, which is typically undesirable. Even in the absence of syneresis, a gelled fuel tends, to a greater extent than a paraffin candle, to pick up fingerprints and so does not maintain a transparent surface.
Accordingly, there is a need in the art for transparent candles that do not feel oily to the touch, do not create fingerprints when handled, and if syneresis does occur, the syneresis does not impact the feel of the candle. As disclosed herein, the present invention is directed to fulfilling this and related needs.
SUMMARY OF THE INVENTION
The present invention provides a curable composition that is placed on a candle, and then the composition is exposed to curing conditions such as ultraviolet light, to thereby cure the coating composition and provide a candle having a cured coating. The curable composition may be the reaction product of TMPTA (trimethylolpropane-triacrylate), itself the reaction product of trimethylolpropane and acrylic acid) and oleyl amine (an unsaturated primary amine having eighteen carbons). The candle may be made of wax or a gelled solvent, i.e., a mixture of gellant and solvent, particularly a hydrocarbon or other low polarity solvent. The undiluted coating may be applied by spraying on the oily surface of the candle. Ultraviolet cure of the coating occurs in 1-2 seconds.
Thus, in one aspect the invention provides a candle, where the candle includes a wick, a fuel, and a cured coating. The fuel may be or include a gellant, such as ETPA or ATPA gellant, in addition to a solvent that it gelled by the gellant, such as mineral oil or a fatty acid triglyceride. The fuel may also be or include wax. The candle may contain more than one visible phase, for example, the candle may include one or more icons set within the fuel.
The coating may be a UV-cured coating. A preferred UV-cured coating includes a reaction product of a tri(meth)acrylate, i.e., a triacrylate or a trimethyacrylate or a mixture of three of acrylate and methacrylate, and a primary amine. The tri(meth)acrylate may be the esterification product of a triol and acrylic acid, and the primary amine may be a primary C
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fatty amine. An exemplary esterification product of a triol and acrylic acid is trimethylolpropane triacrylate, and an exemplary primary C
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fatty amine is oleyl amine. The coating also preferably includes a leveling agent, which when present provides a smoother coating with better adhesion to the candle. The coating also needs to contain a photoinitiator when the coating is to be cured by UV-radiation. The coating may, but need not also include one or more additives selected from colorant, fragrance, flame retardant and insect repellant.
Thus, the present invention provides a candle that includes a wick, a fuel, and a cured coating, where the cured coating is the reaction product of UV-curing a coating composition. The coating composition includes a reaction product of a primary C
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fatty amine with a poly(meth)acrylate, a leveling agent and a photoinitiator. In preferred embodiments, the primary amine is oleyl amine and the poly(meth)acrylate is trimethylolpropane triacrylate.
In another aspect, the present invention provides a method for coating a candle using a curable composition. The method includes (a) reacting a primary amine with a triacrylate to form a product; (b) applying the product to a surface of a candle to provide a curable coating on said candle; and (c) curing the curable coating with radiation, to provide a cured coating on said candle. The product may be applied by, e.g., spraying, brushing, dipping, or sponging, where spraying is a preferred method. The coating composition may be applied more than once, to provide a multiply coated candle. The multiple coatings may look the same or different. When the curable coating is cured by UV radiation, the product further should include a photosensitizer or a photoinitiator. In addition, to assist in wetting the surface of the hydrophobic surface present in the candle, the product may further include a leveling agent or a flow modifier. A suitable flow modified is a copolymer of ethyl acrylate and 2-ethylhexyl acrylate, where the copolymer has a viscosity at 25° C. of 5,000 to 12,000 centipoise. The primary amine is preferably a C
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primary amine, where the fatty nature of this type of primary amine enhances the ability of the curable composition to adhere to the hydrophobic surface of the candle. Oleyl amine is a suitable fatty primary amine. Trimethylolpropane triacrylate is a suitable triacrylate.
Thus, the present invention provides a method for coating a candle using a curable composition, where the method includes (a) reacting a C
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primary fatty amine with a triacrylate to form a product, the product further comprising a photoinitiator and a leveling agent; (b) applying the product to a surface of a candle to provide a UV-curable coating on said candle; and (c) curing the curable coating with UV radiation, to provide a cured coating on said candle. In one aspect of the invention, the leveling agent is a copolymer of ethyl acrylate and 2-ethylhexyl acrylate, said copolymer having a viscosity at 25° C. of 5,000 to 12,000 centipoise.
In another aspect, the present invention provides a radiation curable composition that includes a reaction product of a primary C
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fatty amine with a poly(meth)acrylate. In preferred embodiments, the amine is oleyl amine and/or the poly(meth)acrylate is trimethylolpropane triacrylate. In one embodiment, the composition also includes a leveling agent, such as a copolymer of ethyl acrylate and 2-ethylhexyl acrylate, where the copolymer has a viscosity at 25° C. of 5,000 to 12,000 centipoise, and in one aspect has a viscosity of 20-5000 cps at 25° C. The composition may also include a diluent, and should, prior to exposure to UV radiation, also include a photoinitiator in an amount effective to initiate the UV cure.
Thus, the present invention provides a UV-curable composition that includes a reaction product of a primary C
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fatty amine with a poly(meth)acrylate, wherein the primary amine is oleyl amine, the poly(meth)acrylate is trimethylolpropane triacrylate, and where the composition further includes a leveling agent and a photoinitiator. The leveling agent may be a
Gordon Ronald L.
Jones Raymond H.
Moses Charles D.
Arizona Chemical Company
Hampton-Hightower P.
Seed Intellectual Property Law Group PLLC
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