CROSS REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/345,072 filed Jan. 4, 2002.
- BACKGROUND OF THE INVENTION
This invention relates to the controlled placement of wicks in a candle product. The invention specifically relates to the placement of a candle wick a sufficient distance from the bottom of a candle product in order to create a product in which a burning wick will be extinguished by the molten solid fuel pool when the wick is expended. By quenching the burning wick with molten solid fuel, burn through of freestanding candles placed on a combustible surface is minimized. In a preferred embodiment of the invention, this invention relates to a process for manufacturing a compression molded candle product having a contour in the bottom of the candle form that allows for the controlled placement and sealing of wicks in free-standing candles.
Candles have become a very popular form of air freshening for the home in recent years. Candles are offered that appeal to the olfactory as well as the visual sense, and come in a variety of forms and shapes and combination of both decorative and fragrances. A popular form of candles offered are in the form of freestanding, or pillar candles.
A common manufacturing practice for insertion of wicks on freestanding candles is during the formation of the candle. Specifically, wicks are place into die molds, then a fuel source, such as paraffin wax is poured into the mold and allowed to cool, or prilled wax is poured into a mold and compressed to form a candle shape and a wick is then inserted. It is common practice that the bottom of the wick be in contact with the bottom of the candle shape. The result is a wick that extends the full length of the candle.
The recent increase in candle sales also resulted in an increase of accidents by candle fires in consumer's home. A closer study of the cause of fires can be attributed to candles that are allowed to bum until the flames bum through bottom and cause surface damage from heat or worse combustion of near by flammables. More commonly, freestanding candles can present fire issues when left unattended and allowed to bum to the bottom of the candle and thus cause surface damage or worse ignition of near-by combustibles, or become tipped over allowing the flame to extend beyond the sidewall or bottom of the candle resulting the same effect of ignition of near-by combustibles.
Another manufacturing practice is to form a freestanding candles in molds and insert the wicks afterwards. The practice is to insert the wick and secure to the candle from the bottom, but has drawbacks and limitations. Wicks are inserted into the candles for positioning away from the bottom, there is no assurance of controlled placement. To be accurate, and to control the problems mentioned above, careful wick placement is required. If the bottom of the wick is placed too high in a candle, this will limit the enjoyment obtained by the consumer in burning the candle, and a large portion of the candle will be wasted. Conversely, if the bottom of the wick is placed too close to the bottom of the candle bum through, and combustion of the surface on which the candle is placed can occur.
For purposes of commercial-scale manufacture, there can be an economic advantage in utilizing a design to the bottom of a freestanding candle that allows for the controlled placement and securing of wicks by means of forming the candles in molds.
The description of the present invention includes the advantages of inserting wicks to a specified depth from the bottom of the candle as a way to address any issues of bum through, as well as economic advantages to manufacturing by providing a contour to the candle which allows for the reclamation of scrap materials.
- THE INVENTION
A further advantage, with respect to the production of multilayer, multicolored candles is the ability to dispose of place scrap wax in the bottom cavity.
Wright et al, U.S, patent application no 0010030195 describes the dangers of flash-over from candles allowed to burn to a shallow pool which can ignite if the temperature of the wax reaches its ignition points. Moreover, this invention describes the phenomenon associated with candles in metal containers.
Candle compositions comprised of mineral oil and various polymeric additives are known to develop the phenomenon of flashover due to the inherent nature of these compositions to build up heat in the melt pools which can reach the ignition point. Flashover can occur any time during the combustion of these compositions, so placement of the wicks away from the bottom can offer only limited benefits.
BRIEF DESCRIPTION OF THE DRAWINGS
Candle compositions comprised of wax and respective additives and molded into the form of freestanding candles can only exhibit flashover when the pools are contaminated with objects intentionally, and when contained in some form of a container. A more common observation associated with freestanding candles is the loss of sidewalls from other means such as improper selection of wicks, or contamination of pools.
FIG. 1 shows a freestanding candle;
FIG. 2 is a bottom perspective view of the freestanding candle of this invention showing the bottom cavity;
FIG. 3 is a cutaway view of a freestanding candle showing the cavity and wick placement;
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 4 is a bottom perspective view of the free standing candle of this invention showing the bottom cavity filled with a fuel source, optionally scrap wax.
FIG. 1 shows a freestanding candle 2 having horizontal top 4, sides 6 and bottom 8. Axially disposed wick 10 runs the length of candle 2 from the top 4 to the bottom 8. The top 4, sides 6, and bottom 8 define a candle shape which can be prepared by a variety of methods. Among the methods that can be used are the pouring of molten solid fuel, generally a paraffin or vegetable wax into a mold defining the desired candle shape, such mold optionally containing, placed therein a wick material of suitable construction which will burn with the desired properties. Optionally, the wick 10 may be placed into the candle shape after it has been removed from the mold by forming a wick channel or cavity, and then inserting the wick. The wick should extend a flame sustaining distance, generally ¼ to 1 inch above the top 4 of candle 2 and more preferably generally at least ½ inch above the top of the bottom cavity. Wicks longer than 1 inch may bend over and create undesirable wax pools when the candle is burnt. Wicks shorter than ¼ inch are difficult to light, and are sometimes difficult to sustain a flame since they can be quenched by the capillary action of the solid fuel source, generally a vegetable or paraffin wax.
Another method of forming candles is by compression. In this method prill or powder is formed from the wax, inserted into the mold, and then the wax is compressed in the mold to form the candle shape. The shape is removed from the mold, a wick cavity created, and a wick inserted. The fuel for either poured or compression molded candles may contain colorants, volatile active ingredients such as fragrances, insect control chemicals, sanitizers, deodorants, or the like. In addition the fuel may contain microcrystalline wax to provide improved candle properties, and C14-C20 fatty acids to also enhance the properties of the particular wax fuel employed. Sometimes synthetic wax crystal modifiers such as ethylene-alpha-olefin copolymers such as those sold under the trademark Vybar may be added to the mixture as well. It is not within the scope of this specification, or this invention to specify particular wax or fuel formulations used for candles, and the method of this invention will perform with any candle made in accordance with the teachings herein. Likewise, it is not within the scope of this specification to discuss the choice of proper candle wicks, and those skilled in the art of candlemaking will readily appreciate the various wick materials that are available for particular uses. It is not important in the function of this invention that the candle contain a volatile active material, this invention having applicability to candles providing light only. Likewise, the invention is applicable to any candle shape, for example the common cylindrical shape, square shapes, parallelogram shapes, triangles, etc. so long as the candle 2 has a relatively flat surface for balancing on a surface without falling over.
With specific reference to the drawings, this invention is directed to a meltable solid fuel candle 2 having a substantially horizontal top surface 4, a substantially horizontal bottom surface 8, one or more side surfaces 6 communicating with the top 4 and bottom 8 surfaces to define a shape, and one or more vertical wick cavities 40 running 20 substantially vertically from the top surface 4 to the bottom surface 8 of said shape, each vertical wick cavity 40 having disposed therein a combustible wick 10 having an upper wick end 11 and a lower wick end 9 to form the shaped candle 2, the upper wick end 11 extending above the candle top surface a flame sustaining distance, and which upper wick end when ignited can sustain a flame with the solid fuel, the flame generating sufficient heat to melt at least a portion of the solid fuel below the upper wick end to form a pool of the molten solid fuel immediately below the upper wick end, and to cause the molten solid fuel to move up a portion of the wick 10 by capillary action to the upper wick end 11 to be consumed by the flame, the lower wick end 9 of each wick 10 being located substantially near the bottom horizontal surface of the candle 8, the improvement comprising placing the lower wick end 9 a flame extinguishing distance 22 above the bottom horizontal surface of the candle whereby the pool of molten solid fuel formed by the flame heating the solid fuel extinguishes the flame upon the consumption of each wick 10 and prior to any contact of the flame or the molten solid fuel with a surface communicating with the bottom surface.
With further reference to the drawings, FIG. 2 shows a bottom perspective view of a candle 2 of this invention showing bottom cavity 20 of the invention. Bottom cavity 20 has sides 22 and top 24 which define the cavity. Wick hole 26 extends through top 24 into the cavity 20. Cavity 20 can be prepared by various means. It can be molded into the candle as it is poured, drilled out of a candle after pouring, or in compression manufacturing techniques, can be incorporated into either the bottom of the compression mold, or the ram which is utilized to compress the fuel source in the mold. Bottom cavity 20 does not extend the entire width of the candle, leaving sides 6 and shoulder 30 to support the candle. The sides 22 of cavity 20 can extend from the bottom of the candle shoulder 30 to as high in the candle as it is desired to eventually extinguish the flame on wick 10. Normally, sides 22 should extend a minimum of about ¼ inch above the bottom of the candle.
FIG. 3 shows a cross section view of candle 2. In this view the bottom cavity 20 is shown along with sides 6, shoulder 30, cavity sides 22, and bottom cavity top 24. In this view, the wick cavity 40 is also shown. Wick cavity 40 shows a axially disposed vertically placed wick cavity adapted to receive an appropriate wick 10. In practice, wick 10 would be placed within wick cavity 40 and extend about ¼ to about 1 inch above the top 4 of candle 2. Likewise wick 10 would end at the top 24 of bottom cavity 20, or slightly above top 24 where in practice it would be anchored with a molten wax material. The placement of wick 10 slightly above the top 24 of bottom cavity 20 helps insure that the flame when wick 10 is ignited will be extinguished with the wax pool formed, and will not be in a sufficient downward location to ignite a flammable surface onto which free standing candle 2 may be inadvertently placed. Wick 10 may be held in place by a small amount of molten fuel poured of the same or different composition as candle 2 provided that the material used to anchor wick 10 should be compatible and adhere to the material used for candle 2. In a preferred practice, wick 10 is placed ⅛th inch below the surface of the top 24 of cavity 20 which is ⅜ inch to give a total flame extinguishing distance of approximately ½ inch. In other words, the wick is slightly recessed into the candle body and does not extend into the cavity 20. This feature does not detract from the utility of the invention when the wick is flush with top 24 or even extends into cavity 20 so long as the wick is a flame extinguishing distance above the horizontal bottom 8 of the candle. When a cavity is utilized, the wick should preferably extend substantially no further than the top surface of the bottom cavity.
FIG. 4 shows a bottom view of candle 2 showing bottom cavity 20, bottom cavity sides 22, bottom cavity top 24 and wick cavity 40. Also shown in dotted line is wax fill 44 which is added to hold wick 10 in place and to provide a better foundation upon which candle 2 may rest, hopefully on a non-combustible surface. One of the surprising benefits of the flame extinguishing feature of this invention, is that it provides both economic and safety benefits.
Many times in the manufacture of candles different waxes are employed. These waxes may contain different colorants or pigments, and thus, must be carefully sorted if they are to be reused, or the material, if commingled must be disposed of as a chemical waste. This is of special concern when the solid fuel being used contains different fragrance materials that may or may not be compatible to the olfactory sense. Previously, waste wax from broken or scrap candles was disposed of at great economic cost. If the solid fuel being commingled contained different colorants, often a gray or dark unpleasing color would result if the scrap was melted down and reused. This melted down scrap was unsatisfactory for candle production since it did not provide proper esthetics for a commercially saleable product. We have found that when wax scrap is collected and melted, it may be used to fill the bottom cavity 20 to provide additional support for candle 2 since the wax contained in bottom cavity 20 is not consumed in the combustion of the candle. This scrap wax is thus contained in the candle and provides stability and support to the sides 4 and shoulder 30 of candle 2. The scrap wax may also help maintain the wick at a satisfactory location, preventing it from sliding down. In the absence of scrap wax of course, new wax can be utilized, and this invention is not meant to be limited to the use of scrap wax alone. Alternatively, and assuming that shoulder 30 and sides 6 remain intact and are strong enough to maintain the weight of the candle, the bottom cavity may be left open. The scrap wax does not prevent the wick from sliding down when a sealing wax is utilized, thus explaining why the cavity can remain unfilled and the wick will extinguish. As long as the melt point of the sealing wax, the wax that anchors the wick, is not substantially higher than the melt point of the formula, the wick will fall over and will not slide down. When no sealing wax is utilized the wax placed into the cavity will help to maintain the wick in its proper location. We prefer to use sealing wax however to maintain the placement of the wick at a desired location.
In the manufacture of candles by compression techniques, such as that disclosed in my commonly assigned application filed of even date, the compression candle is molded upside down with a compression ram, having the desired shape to impart the bottom cavity 20 incorporated into the ram. After compression, the candle shape is removed from the mold, and still upside down, a wick of suitable material is inserted. This wick 10 is in the wick cavity 40, placed about ⅛ th inch beneath the top 24 of candle bottom 8. The wicks utilized may be of any conventional wick material including but not limited to cotton, cotton/paper, cotton/linen, or synthetic such as rayon. A preferred wick material is cotton with or without paper braid or a paper core.
In practice, we prefer not to use metallic wick clips as are commonly used for the support of wicks, in for instance votive candles because free standing candles are often placed upon stands having protrusions which engage the candle and steady the candle. Such protrusions would damage a wick clip, and hence, while this invention will function, we prefer not to use such devices. Another disadvantage of a conventional metallic wick clip in the practice of our invention is that the metal will conduct heat, melting additional wax, and perhaps causing the fuel around the wick clip to melt. This additional melted wax may cause breakthrough of the wax to the bottom of the candle, exposing molten wax to the surface upon which the candle is to be placed.
The example presented below illustrates the preparation of a multiple layered compression molded candle product having the wick shut off feature, and the scrap disposal feature of the subject invention. As will be seen, while this invention is illustrated with a compression candle making technique, those skilled in the art will readily appreciate that the subject wick shut off invention will have applicability with regard to candles that are poured as well.
For each composition of a layer, a refined paraffin wax (IGI Paraflex 1239 MP 60° C.); is pre blended with an ethylene derived polymer (Vybar 103, MP 76° C.) until the polymer is fully integrated into the refined paraffin wax. A fragrance/dye/UV inhibitor concentrate of IFF Stargazer 18 (available from International Flavors & Fragrances), Sandoplast Yellow 3G, Sandoplast Red 2G (both available from Clariant Gmbh, Pigments and Additives Division, Frankfurt) and Cyasorb UV 531 (available from Cytec Industries, Inc., West Patterson, N.J.) is mixed until all components are dissolved.
The following four streams: wax/polymer pre-blend and the fragrance/dye/UV inhibitor concentrate, stearic acid (Emersol 150 MP 65.5° C. available from Henkel Corp.), and microcrystalline wax (Bareco's Victory Lite Wax MP 80° C.) are metered simultaneously to the formula (using a four stream metering system) and are blended through an in-line blending process.
Separately and simultaneously, additional compositions are prepared using the same method of mixing process. For the second layer, a refined paraffin wax (IGI Paraflex 1239 MP 60° C.); is pre blended with Vybar 103 until the polymer is fully integrated into the refined paraffin wax. A fragrance/dye/UV inhibitor concentrate of IFF 1814 HBA, Clariant Sandoplast yellow 3G and Cyasorb UV 531 is mixed until all components are dissolved. The wax/polymer pre-blend and the fragrance/dye/UV inhibitor concentrate are further blended through an in-line blending process with the same stearic acid and microcrystalline wax used in layer mixture 1. A third layer using identical ingredients, except the fragrance/dye/UV inhibitor concentrate was IFF Moonblossom 47, Clariant Sandoplast Green 3G, Nitro Fast Blue 2B and Cyasorb UV 531 is mixed until all components are dissolved. The wax/polymer pre-blend and the fragrance/dye/UV inhibitor concentrate are further blended through an in-line blending process as with the other two layers.
The separate layer mixture-candle wax compositions are held at a temperature of approximately 65 to 80° C. usually 75-80° C., and preferably about 77° C. and pumped separately to respective surge tanks until the ingredient mixtures are homogenous. The candle wax compositions are then pumped to their respective separate wax reservoirs in Kurschner wax spray drum system and the compositions are held at a temperature of 65 to 80° C. The spray drums are set to a speed of approximately 42 meters/min. The spray room temperature is held to about 15° C. and the relative humidity of approximately 50% although this temperature parameter may vary depending on the composition being dried, the humidity, the rate of spraying, and the temperature of the material being sprayed. The candle wax composition for each layer is pumped through a spray manifold system from the spray drum reservoir and sprayed to 15 centimeters above the drum from nozzles. The wax is sprayed into the air and semi-solidifies before contacting the drum surface. The spray drum is held to a temperature between about 7 and 24° C. The prilled wax is collected on the spray drum and them scraped from the drum and transferred into a vibrating conveyer that leads inside the drum for each of the compositions for further cooling. The prilled wax is collected at the end of the drum and vacuum fed into holding separate hoppers. For consistent cavity mold filling and compression for multiple layers in a single mold, the prilled waxes are maintained at temperatures between about 17 and 32° C.
The target dimension for the candle directly from the press is 7.60 cm by 10.16 centimeters in dimension. For a pillar candle of this dimension, the total weight is about 366 grams and the weight for each layer is about 122 grams. It should be noted that the candles are made on the basis of volume and weights are given for the purpose of illustration only.
The prilled candle waxes above are transferred from the spray drum to three separate stationary hoppers and maintained at a temperature between 20 and 32° C. The prilled waxes are transferred from the stationary hoppers to feed tube matrix of the Progressive Automation compression mold pillar candle press.
The feed tube matrix consists of 3 rows each containing 6 cavities which are filled with prilled wax for each layer. The feed tube matrix passes over the a stationary table of the press and fills one of the two sets of 6 cavity head units with a volume of 122 grams from the feed tube matrix for a layer per candle, until the cavity is filled with a total of 366 grams of prilled wax, thus representing three distinct layers of prilled wax composition in a single candle. The table then rotates one of the 6 head cavity units filled with the three prilled wax compositions, 180 degrees to a compression station, where the prilled wax is compressed in the cavity from the top down, forming a contour pocket of approximately 40 millimeters by 9.5 millimeters in dimension to the bottom of the candle. The prilled waxes are compressed to a force between 2400 and 2800 pounds, for a dwell time of approximately 1-5 seconds to produce a candle that is of a density of between 0.83 and 0.92 grams/cubic centimeter, at which time, the cavity molds are heated through the use of a water jacket, to a temperature of between 10 and 40° C.
The compressed candles are then extracted from the cavity molds, then placed onto a pocketed indexing conveyer system, bottom side up to allow for a clearance space for the top of the candle, and transferred to a Progressive Automation wicking machine where cotton wicks, with or without paper braids or paper cores having a length of from about 9 to about 11.5 cm. from Technical Braiding Gmbh are inserted into the candles from the bottom to allow the wicks to be placed flush to the upper portion of the pocket and to a total depth of ½ inch from the bottom of the candle. While the candles are inverted with the bottom up, the wicked candles are dosed with approximately 0.2 to 0.5 grams of paraffin wax at a temperature between 65 and 85° C. to seal the wicks in place. While microcrystalline wax can be advantageously used in this step, it is preferred to utilize a material having the same properties employed in the bottom layer so that the wax material is compatible with, and has the same melting point as the main structure. The candle is then transferred onto a second station where the cavity is filled with between 8 and 10 grams of candle wax that has been reclaimed from scrap candles, and at a temperature between about 60 and about 80° C. and generally about 60-70° C. This temperature range is not critical, and molten paraffin of a higher or lower temperature can be used so long as the temperature is not high enough to damage the structure, or dislodge the wick. The candles that have been filled with wax into the bottom cavity are then passed through cooling tunnel at a temperature of from about 13 to about 25° C. for a period of approximately 12 to 20 minutes. In the practice of this invention it is necessary that the selected wick extend out of the top of the candle a flame sustaining distance. In practice this distance ranges from about ¼ inch to about 1 inch.
The resultant candles were esthetically pleasing, had satisfactory burn characteristics and emitted fragrance as they burned. When the candles of the subject invention were utilized the wick was extinguished by the molten wax pool. Over a series of candles that were tested, burn though was virtually eliminated.