US3702495A

US3702495A - Method of producing compression molded candles

Info

Publication number: US3702495A
Application number: US70390A
Authority: US
Inventors: Ronald R Renoe
Original assignee: Hallmark Cards Inc
Current assignee: Hallmark Cards Inc
Priority date: 1970-09-08
Filing date: 1970-09-08
Publication date: 1972-11-14
Anticipated expiration: 1989-11-14

Abstract

A method and apparatus for forming a candle from a particulate wax material utilizes a compressive force of at least 2,000 p.s.i. to form the material into a self-sustaining body for a freestanding candle comparable in strength and appearance to a cast candle of the same size. The extremely high pressure forms the particulate material into a candle body wherein the amount of entrapped air is minimized for maximum color density and elimination of granular surface appearance as opposed to prior methods of compression molding where only partial compression resulted in candles each having a surface where the particulate nature of the starting wax material is clearly visually evident. The method is carried out utilizing an open-ended mold, one end of which has been closed and into which a wick rod has been inserted for forming a wick hole in the candle blank. Particulate wax material is introduced into the mold and a piston is moved against the material under a pressure of 2,000 to 10,000 p.s.i. The closed end of the mold is then opened after which the candle blank is ejected. A candlewick is then inserted into the hole in the blank to complete the candle.

Description

United States Patent [1 1 5 Renoe [4 Nov. 14, 1972 METHOD OF PRODUCING [57] ABSTRACT COMPRESSION MOLDED CANDLES A method and apparatus for forming a candle from a [72] Inventor: Ronald R. Renoe, Mission, Kans. particulate wax material utilizes a compressive force of at least 2,000 psi. to form the material into a self- [73] Asslgnee. c z r hf Incorporated Kansustaining body for a freestanding candle comparable Sas in strength and appearance to a cast candle of the [22] Filed: Sept. 8, 1970 same size. The extremely high pressure forms the particulate material into a candle body wherein the [21] Appl' 70390 amount of entrapped air is minimized for maximum color density and elimination of granular surface ap- 52 US. Cl. ..29/428, 264/102, 264/109, pearance as opposed to prior methods of compression 2 4 319 molding where only partial compression resulted in 51 Int. Cl. ..,..B2sb 3/02 candles each having a Surface Where Pamieulate [58] Field of Search ..431/288; 264/102, 109, 319, name of Stming Wax material is clearly visually 264/334; 18/1 K, 27 2 425 29/428 evident. The method is carried out utilizing an open- J ended mold, one end of which has been closed and [56] References cued into which a wick rod has been inserted for forming a wick hole in the candle blank. Particulate wax materi- UNITED STATES PATENTS al is introduced into the mold and a piston is moved against the material under a pressure of 2,000 to K PIS-i. The closed end of the mold is then Heinflch opened after the candle is ejected. A 3,026,572 Reick X dlewick is then inserted into the hole in the blank to 2,679,069 5/1954 Keogh ..l8/l K complete the Camila Primary Examiner-Robert F. White 19 Claims, 6 Drawing Figures Assistant Examiner-T. E. Balhoff Att0rneySchmidt, Johnson, Hovey, Williams and Chase Compression 5T anon 3 fiorgriressiom- Wick Rod Holder" 0 s Fi c: a 222 36 E/ v WlCk R5213 Die -12 Piston Die Assembly Candle 24 6 Support Rail Blank 6% /l 32 46 Die Plate f/Plof PATENTEDWW H 5,702,495

2 i o 2 Wick Rod Holder Wk Rod Holder 17 .2.

Q4 22 25 f Pislon Q2 Pislon I t 24 Char in Chule Wick Rod P f l f aricuoe l8 s,- TR Js wax */7Die Die 4 6 Die Assembl /,7 Spike Hole Form 5 i Raj Die PIoTe 44 E l I Die Plofe p l4 Assembly L 0' Ch Slafion Die Plole 34 fig sl glion Supports g fig E jeclio n Station 44 Compression Ram 14a 121 9. Slalion 35 i 42 Compressi0n- Wick Rod Holder Rods n! n 22 QQ FT 2Q 26 36- [5 Q Wick Rod oie [2 "12 Wick ROd\ Piston lg I 7 Die $1 Die Assembly cans/e3 g Supporl Roll 12 Blank 7;

/l l 32 i l Mfl,; p 1 i Die Assembly I! Suppor 94 Q \fl Die Plole p t 4 L 48 s s 46 i 40 46 6* Candle Blank 66 7 Candle Die Plafe 50 ?%"Blonk INVENTOR. 54 Ronald R. Renoe wlCk g- 7 BY //Spike Hole W F 8.6. w 92:?

ATTORNEYS.

METHOD OF PRODUCING COMPRESSION MOLDED CANDLES This invention relates to a method and apparatus for the compression molding of wax candles.

Prior to this invention, highest quality candles were obtained by casting molten wax into a candle mold, a major disadvantage in the casting process is the time required for the molten wax to cool and solidify to permit handling of the candle. Another disadvantage inherent in casting processes for producing candles is the tendency for voids to occur in the central part of the cast candle body, thus causing the wick around which the wax is cast, to be drawn off center and resulting in erratic burning properties. Thus, in the interest of economy, efforts have been made to develop a method of forming candles wherein a more perfect product is produced while at the same time eliminating the timeconsuming step of cooling the molten wax in a mold therefor. Cooling times of up to 12 hours for large cast candles is common in the industry. Processes suggested as alternates to casting have generally been unable to produce a candle of equivalent density to a cast candle, thereby resulting in inferior burning qualities and decreased physical strength. On the other hand, compression molding of candles has many advantages over coasting techniques, particularly from the standpoint of being able to provide polychromatic candles to an extent not possible with casting. Because of the limitations of prior methods of compression molding of candles, such method has been largely limited to forming candles of the religious votive type which are adapted to be supported by auxiliary structure and the melted candle wax contained in a receptacle therefor. Such techniques have generally not been applicable to freestanding candles.

It is, therefore, a principal object of the present invention to provide a method and apparatus for compression molding a candle body from particulate wax material wherein the material is coalesced under sufficient pressure to produce a freestanding candle having burning, strength and physical appearance characteristics comparable to a cast candle of the same size and color.

Another object of the invention is to provide a method and apparatus for compression molding a candle body from a particulate colored wax material wherein the material is coalesced under sufficient pressure to remove substantially all entrapped air and produce a candle of superior color as a result thereof.

A further object of the invention is to provide a method and apparatus for compression molding a candle from a particulate wax material wherein a candle of superior strength and resistance to warping is obtained by coalescing the particulate material under a compressive force of at least 2,000 p.s.i.

It is also an object of the present invention to provide a method and apparatus for compression molding a candle from a particulate wax material wherein a candle having a density at least as great as that of a cast candle is obtained by subjecting the particulate material to a compressive force of at least 2,000 p.s.i.

Also an important object of the invention is to provide a compression molding process for forming a candle body having characteristics comparable to those of a cast candle of the same size wherein the processing time is effectively lowered from time intervals approaching 12 hours to a time of substantially less than one minute. a

A still further object of the invention is a method and apparatus as set forth in the foregoing objects wherein a high-melt, particulate wax can be utilized to provide a candle of superior handling and storage qualities.

My invention also has as one of its objects a method and apparatus for forming a particulate material wherein the material is compressed and thereby coalesced into a self-sustaining body under a sufficiently high pressure to avoid the need for subsequent tempering, or other strengthening or forming steps.

Still another object of the present invention is a method and apparatus for forming candles from a particulate material wherein the material is compressed under a pressure of at least 2,000 p.s.i. to produce a candle having an even surface free of irregularities which exhibits superior light-reflecting properties.

It is also an object of this invention to provide a freestanding wax candle formed by coalescing particulate material under a force of at least 2,000 p.s.i. whereby the candle is substantially free of entrained air as minute cellular voids or larger air pockets as well and as a result thereof exhibits superior color characteristics and physical strength.

In the drawing:

FIG. 1 is a cross-sectional side view of the candleforming apparatus at the assembly station;

FIG. 2 is an end view of the apparatus as it would appear at the charging station with one of the candle molds being shown in cross section and the other in elevation;

FIG. 3 is another side view of the apparatus as it would appear at the compression station with one of the candle molds being illustrated in cross section and the other in elevation;

FIG. 4 is an end view, similar to FIG. 2, illustrating the molding apparatus at the ejection station where the candle blanks are removed from the molds;

FIG. 5 is a cross-sectional view of the completed candle blank; and

FIG. 6 is a perspective view of the completed candle.

Referring to the drawing, a plate 10 has a plurality of openings therein for receiving four open-ended, cylindrical die molds 12, two only of which are depicted in essentially schematic form in FIGS. l4. It is to be appreciated in this respect that any number of molds can be employed, limited only by practical production and engineering considerations. Each of the molds 12 is disposed in an upright position and has its lower end closed by a die plate 14. Each die plate 14 is provided with a hollow, open-ended spike hole form 16 which projects upwardly from the die plate 14.

The upper end of each mold 12 receives a wick rod 18 for purposes to be made clear hereinafter. The lower end of the wick rod is received within the spike hole form 16, and the upper end of the rod 18 is surrounded by a cap 22 which also engages the edge of the mold 12. A piston 24 surrounds each of the rods 18 and is in frictional engagement with the latter while still being free to move downwardly within the mold 12. The material-engaging surface of the piston 24 in the form thereof illustrated is outwardly convex to produce a candle of one desired configuration. The wax engaging face of the piston can be of any desired configuration, e.g., flat, concave, provided with raised or indented letters or other indicia, depending upon the nature of the candle body desired for a particular visual effect. Each of the molds 12 has an opening 26 in one side for receiving a charging chute 28 through which particulate wax material 30 is introduced into the cavity of the mold 12.

The plate is supported for movement by a conventional conveyor (not shown) along a vertical support rail 32 disposed between a pair of angle plates 34, the latter providing a support for the die plates 14 disposed in the bottom of each mold 12. Each of the caps 22 preferably has three apertures therein, and a compression rod 36 coupled with a pressure ram 38 pass through each aperture respectively to actuate the piston 24 when the die mold assembly is moved to the compression station as illustrated in FIG. 3. As the of the air entrapped in the interstices of the particulate wax. Generally, at least about 10 seconds up to 80 seconds is an effective compression period at the pressure specified above. This results in complete coalescence of the particulate material30 into a selfsustaining body in the form of a candle blank 46. Finally, the conveyor moves the die molds 12 to the ejection station where ejection rods 42 are inserted into each of the molds 12 and the ram 44 is actuated to continue the downward movement of the piston 24 and thereby eject the candle blank 46 from the lower end of the mold 12. The molds 12 and their die plates 14 would then normally be returned to the assembly station along a continuous conveyor. As a result of the frictional engagement of the piston 24-with the wick rod 18 as the piston moves downwardly'within each of I the molds 12, the rod 18 is placed under tension along molds 12 approach this station the support rail 32 is of to rest upon a lower platen 40 beneath the ram 38.

At the ejection station, the three ejection rods 42 are coupled with a second ram 44 which passes through respective apertures in each of the caps 22 to eject a completed candle blank 46 from the lower end of each of the molds 12. At this point, a pair of supports 48 parallel with the rail 32 provide the necessary stabilization for the plate 10 while permitting the blank 46 to be ejected. As best illustrated in FIG. 5, the completed candle blank 46 conforming to one type of preferred candle configuration has a wick hole 50 and a spike hole 52 centrally disposed along the longitudinal axis of the candle blank. The upper surface of the candle blank 46 illustrated as being concave as a result of the convex configuration of the surface of the piston 24. The completed candle 54 is obtained by inserting a candlewick 56 through the wick hole 50 and securing the same by a knot or other appropriate retainer which can be lodged in the end of the spike hole 52 adjacent the wick hole 50.

In carrying out the method of the invention the die molds 12 are first moved to the assembly station shown in FIG. 1 where the die plates 14 are inserted into the lower end of the molds l2 and the wick rods 18 with the pistons 24 and caps 22 placed thereon positioned in the respective molds 12. It will be appreciated that once the lower end of the rod 18 is inserted within the spike hole form 16 and the cap 22 placed upon the mold 12, the rod is restrained against lateral movement relative to the mold. The conveyor (not shown) then moves the assembly of the die molds 12 along the rail 32 to the charging station where chutes 28 are positioned within the openings 26 and the particulate wax material 30 is deposited within each of the molds 12.

Next, the conveyor moves the assembly of molds 12 along the rail 32 to the compression station where the compression rods 36 are inserted into each of the molds 12. The material 30 is then subjected to a compressive force of at least 2,000 p.s.i. and sufficient to cause the particulate material to coalesce into a selfsustaining body by moving the pistons 24 downwardly in a direction axially of the mold 12 under the force of the ram 38. Preferably, the force exerted by the ram 38 is within the range of 4,700 to 6,000 p.s.i. with the higher pressure value being preferred and this force is maintained for a sufficient time to expel most if not all its longitudinal axis to preclude any movement of it and thereby assure that the resulting wick hole 50 is exactly positioned in the center of the blank 46 and is free of irregularities. The wick rod 18 operates to forma centrally located aperture in the candle blank body for receipt of a wick therein which then extends truly axially of the candle. It is not feasible to compress the wax around a wick because the latter would simply wad up in the mold cavity under the high pressure applied'to particulate wax material in the mold. There is no tendency for this result to occur in connection with'the relatively rigid rod 18 though since it is held by the wick rod holder as the. compression piston moves downwardly in the cavity and the forces thereon are evenly distributed thereon. In order to reduce the amount of airentrapment in the final candle blank, a vacuum of the order of 28 in. Hg below atmosphere may be pulled on the mold cavity during compression molding at a point above the level of the powder introduced into the mold.

The preferred particulate wax material tobe used in the specific process detailed above comprises a major proportion of paraffin having a melting point of at least about (measured with a Perkin-Elmer differential scanning calorimeter). This relatively high melting material results in a candle which can be shipped and stored without danger of warpage as a result of excessiveheat. Generally, the wax material will have a melting point within the range of 124 to 154 F. Compressed candles produced from these wax materials offer a very good surface finish without the cost of highly polished molds. It is to be understood though that this invention is not limited to that particular wax composition, and other candle formulations may be employed so long as the particles thereof may be substantially coalesced under pressure to produce a selfsustaining body which gives the appearance of having been cast and burns with essentially the same properties as a cast candle. The particulate material can be prepared in any conventional manner although optimum results are obtained when initially liquid paraffin or equivalent material is sprayed through a nozzle into the atmosphere and allowed to solidify into particles having a size of from 0.5 to 300 microns in diameter. Any of the conventional pigments and dyes now in use for coloring the wax used in casting candles may be used in the present compression molding process. In the above, it has also been found desirable to incorporate at least 0.5 percent by weight of stearic acid as a vehicle in those cases where a coloring pigment is added to the wax. Other additives such as fatty acid esters (C to C fatty alcohols (C to C ethyl alcohol and fatty amides (C to C may also be introduced into the wax formulation to enhance the appearance, processing ease or physical characteristics of the final product. The amount of additive to be introduced may be varied depending upon the nature of the candle product to be produced. For example, usually about percent of stearic acid is the useful upper limit thereof. The method is also advantageous for producing polychromatic candles by introducing into the molds layers of different colored particulate material or blends of large particles of various colors. ln addition, appropriate dividers which extend longitudinally of the molds 12 can be utilized to permit the introduction of different colored wax materials with the resulting candle having colors which extend longitudinally of it.

In forming a candle according to the above described method, complete coalescence of the particulate material is obtained as a result of the high compressive force applied. This complete coalescence removes the need for tempering or further forming steps and the resulting candle is a self-sustaining, freestanding body with superior physical characteristics. The high compressive forces utilized in the instant invention result in a completely homogeneous candle body as contrasted with candles previously made by compression molding which did not have this property. It is this ability to obtain complete homogeneity which makes the method of the present invention particularly adapted to obtaining colored candles by using colored wax to a degree not previously possible. In addition, the complete coalescence of the particulate material results in an even candle surface with superior light-reflection characteristics and hence more vivid color. The vividness of the colors of candles produced in accordance with this invention is believed to be attributable in large measure to the lack of significant air entrapment in the final compression molded blank. Air is an excellent light scattering medium and thus it is essential that it be eliminated from the candle body if the color thereof is to be equivalent to a cast candle where air entrapment is not a problem. However, it was unexpectedly discovered that particulate wax could be compressed in a short period of time at pressure above 2,000 p.s.i. and obtain substantially complete coalescence of the wax and consequent expulsion of air from the candle blank.

While it was previously felt that high compressive forces should not be utilized in the compression molding of candles from particulate wax material because of the danger of forming discontinuities in the finished candle, the unexpectedly superior candle which is obtained by the method of the present invention is directly attributable to the extremely high pressure utilized. While there is no upper limit on the magnitude of the compressive force which can be utilized in the method of the invention except from the standpoint of practical commercial operation, it has been found that no significant product improvement is obtained above about 10,000 p.s.i.

It is contemplated that the invention will find use in candles of all sizes although it is particularly advantageous when employed to construct a candle of at least 3 inches in diameter and 9 to 12 inches in length. Such a candle, when constructed in accordance with conventional casting techniques, would require at least 3% hours to cool after the molten material was introduced into the mold. This cooling step is completely eliminated in the method of the present invention while still obtaining a candle having a density at least as great as that of the cast candle.

While one specific embodiment of the invention has been illustrated and described in detail, it is to be understood that an infinite variety of shapes and sizes of candles can be produced in accordance with the teachings hereof. For example, raised or depressed designs may be formed by providing a separable mold having appropriate design defining depressions or raised areas in the mold surfaces. Similarly, the piston and bottom closure faces may be of different shapes as desired and provided with raised or depressed designs or lettering.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A method of making candle blanks from a particulate wax material in a mold therefor, said method comprising the steps of:

depositing a quantity of said material into said mold;

subjecting said material in the mold to a compressive force of at least 2,000 p.s.i. and sufficient to cause the particulate material to be formed into a selfsustaining body; and

removing said body from the mold.

2. A method as set forth in claim 1, wherein said step of subjecting the material to a compressive force includes maintaining said compressive force on said material. for a predetermined time sufficient. to expel substantially all of the air initially entrapped in the space between the particles of wax.

3. A method as set forth in claim 2, wherein the step of maintaining said compressive force on the material for a predetermined time includes applying such pressure to the quantity of material for a time interval of from about 10 to seconds.

4. A method as set forth in claim 2, wherein said step of subjecting the material to a compressive force includes applying a compressive force of about 6,000 p.s.i. to said material.

5. A method as set forth in claim 1, wherein said mold is of cylindrical configuration and the step of compressing the material comprises applying force thereto in a direction axially of the mold.

6. A method as set forth in claim 1, wherein said material is initially comprised of particles having a size of from 0.5 microns to 300 microns in diameter.

7. A method as set forth in claim 1, wherein is included the step of forming a wick hole in the candle blank simultaneously with subjecting the material to a compressive force.

8. A method as set forth in claim 7, wherein saidmold includes a wick rod disposed therein and said step of forming a wick hole includes depositing said material around the wick rod; and maintaining said rod under tension along its longitudinal axis as said material is subjected to said compressive force whereby movement of said rod relative to said mold is precluded.

9. A method as set forth in claim 1, wherein said material comprises a major proportion of parafiin having a melting point within the range of 124 to 154 F.

10. A method as set forth in claim 9, wherein said particulate material includes a colorant for imparting a color thereto.

11. A method as set forth in claim 10, wherein said material includes a vehicle selected from the group consisting of C to C fatty acids, fatty acid esters, fatty alcohols, and fatty amides.

12. A method as set forth in claim 10, wherein said material includes at least 0.5 percent by weight of stearic acid as a vehicle for said colorant.

13. A method as set forth in claim 1, wherein is includes the step of pulling a vacuum on the area of the mold above that initially occupied by the material during compression molding of said body.

14. A method as set forth in claim 1, wherein is included the steps of providing a separable mold and forming design defining depressions or raised areas in the candle forming surfaces thereof.

15. A method of making a candle from a particulate wax material in an open-ended, tubular mold therefor, said method comprising the steps of:

placing the mold in a loading position;

closing one end of the mold;

depositing a quantity of said material into said mold;

inserting a pressure piston into said mold from the other end thereof; I

moving said piston toward the material to place the latter under a force of at least 2,000 psi. to cause the particulate material to. be formed into a selfsustaining body;

opening said one end of the mold; and

continuing movement of said piston in a direction to eject said candle from said one end of the mold.

16. A method as set forth in claim 15, wherein is included the step of positioning a wick rod in the mold prior to said depositing step to form a wick hole in the body.

17. A method as set forth in claim 16, wherein is included the step of maintaining said piston in frictional engagement with said rod as the piston moves under said compressive force to place said rod under tension along its longitudinal axis and preclude movement of the rod relative to the mold.

18. A method as set forth in claim 16, wherein is included the step of forming a spike hole in said material as the latter is coalesced into said body.

19. A method as set forth in claim 16, wherein is included the step of inserting a Candlewick through said wick hole in the body.

Claims

1. A method of making candle blanks from a particulate wax material in a mold therefor, said method comprising the steps of: depositing a quantity of said material into said mold; subjecting said material in the mold to a compressive force of at least 2,000 p.s.i. and sufficient to cause the particulate material to be formed into a self-sustaining body; and removing said body from the mold.

2. A method as set forth in claim 1, wherein said step of subjecting the material to a compressive force includes maintaining said compressive force on said material for a predetermined time sufficient to expel substantially all of the air initially entrapped in the space between the particles of wax.

3. A method as set forth in claim 2, wherein the step of maintaining said compressive force on the material for a predetermined time includes applying such pressure to the quantity of material for a time interval of from about 10 to 80 seconds.

8. A method as set forth in claim 7, wherein said mold includes a wick rod disposed therein and said step of forming a wick hole includes depositing said material around the wick rod; and maintaining said rod under tension along its longitudinal axis as said material is subjected to said compressive force whereby movement of said rod relative to said mold is precluded.

9. A method as set forth in claim 1, wherein said material comprises a major proportion of paraffin having a melting point within the range of 124* to 154* F.

11. A method as set forth in claim 10, wherein said material includes a vehicle selected from the group consisting of C12 to C26 fatty acids, fatty acid esters, fatty alcohols, and fatty amides.

15. A method of making a candle from a particulate wax material in an open-ended, tubular mold therefor, said method comprising the steps of: placing the mold in a loading position; closing one end of the mold; depositing a quantity of said material into said mold; inserting a pressure piston into said mold from the other end thereof; moving said piston toward the material to place the latter under a force of at least 2,000 p.s.i. to cause the particulate material to be formed into a self-sustaining body; opening said one end of the mold; and continuing movement of said piston in a direction to eject said candle from said one end of the mold.