Patent Application
20140234557
Embodiments of the present invention relate generally to artificial carvable pumpkins and their methods of manufacture. Specifically, the embodiments described provide methods of forming the pumpkins with a substantially uniform or otherwise controllable, definable skin thickness, which eases the carving steps. The embodiments also provide enhanced flame retardance and increased pigment retention features.
Embodiments of the invention relate to novelty items and their manufacture, particularly to items such as artificial pumpkins that the consumer desires to carve or alter after purchase. Artificial novelty articles such as Halloween jack-o-lanterns are typically manufactured from paper products, ceramics, or thin, soft plastic and, while useful for display, are not suitable for carving by the purchaser. To honor the holiday tradition of carving pumpkins, people must typically purchase a real pumpkin, which can perish and rot after a short period of time, can be messy and smelly to carve, and is not reusable in subsequent years, such that a small child's carving creation is not savable for future reminiscing. One solution has been to provide artificial pumpkins that can be carved. Examples of such carvable pumpkins are described in U.S. Pat. No. 5,491,007, the entire contents of which are incorporated herein by reference. These pumpkins provide a polyurethane foam that can be used to create a three-dimensional hollow structure.
Although such pumpkins have been commercially successful, there are improvements that need to be made. For example, the earlier pumpkin versions are typically manufactured by spraying a polyurethane foam inside a mold and allowing the foam to rise. The mold may also need to be spun or rotated in order to allow the foam to diffuse along the mold interior. These methods have the downside of providing a pumpkin that potentially has an uneven skin thickness. Additionally, improvements in flame resistance and retardance are needed, as well as improvements in enhanced pigmentation of the pumpkin.
Embodiments of the invention described herein thus provide a carvable pumpkin that is durable, can be reused, that has enhanced fire retardance, and that has a bright brilliant color that remains intact upon carving. These improvements help ensure that the pumpkins are safer, such that if they catch fire, they provide a flame barrier and burn out in about a minute or less. The improvements also help provide brightly colored pumpkins that do not have an external coating or layer of paint that can be easily scratched off. Finally, the improvements help provide pumpkins with a substantially uniform skin or otherwise controllable thickness, which can ease carving and provide an enhanced user experience.
Embodiments of the present invention provide novelty artificial pumpkin that can be easily carved by consumers. The pumpkins are manufactured to have enhanced features over pumpkins of the prior art. As shown in
Carvable pumpkins 10 are generally formed from a polyurethane foam material having a nominal density of about 2.5-3.0 pounds per cubic foot, which has been found to be suitable for carving with simple tools—such as a pocketknife. Polyurethane foam is typically sold and transported as two chemical components, which are mixed together. The foam may be contained in tanks, and a tank containing element A may be connected by a hose to a tank containing element B. The two elements are heated and mixed to provide the pumpkin foam. In a specific embodiment, the components are polyol and isocyanate, in various combinations and percentages. One example of a suitable foam combination is Voracor CS 1635 Polyol and Voracor CE 151 Isocyanate, manufactured by Dow Chemical. However, it should be understood that other manufacturers may have or develop formulations that are suitable for the embodiments described herein. More detailed manufacturing steps are outlined further below.
Once the pumpkin has been formed, the inner 12 and outer surfaces 14 of the pumpkin 10 form a thickness “T” therebetween, with the thickness being about 0.25 inch to about 2 inches, more particularly about 1 inch. This thickness range has been found to provide sufficient strength without excessive pressure required for carving. Examples of a thickness “T” between the surfaces 12, 14 is illustrated in
The outer surface 14 of the pumpkin 10 is also formed as a pigmented surface. The pigment is provided not only by being mixed into the foam as one option, but also (or instead) by being provided on the mold that is used to form the pumpkin itself. The pigment may be sprayed into the mold that receives the exterior coating or onto the mold release layer substance so that the pigment becomes an integral part of the pumpkin as the reaction between the polyol and isocyanate fuse with the pigment applied to the pigmented mold release. This results in the pigment being fused to the outer surface and forming a part of the surface so that it does not flake off. By contrast, forming a pumpkin and then painting the outer surface tends to cause the paint to flake off during the carving process or during storage of the artificial pumpkin. Thus, by providing the pigment actually fused to the outer surface during manufacture, such that it forms a part of the outer surface, the pigment is much more long-lasting and durable. It can also maintain a more brilliant hue. The pigment may be a blend of saturated, hydroxylated polyester and orange pigments.
One way to provide such a pigmented surface is to apply pigment (typically an orange pigment, but it should be understood that any desired color may be used) to the interior of the pumpkin mold during manufacture, and specifically, to a silicone mold release layer applied to the inner surface of the mold. This step provides a pigmented mold release that both releases the completed pumpkin from the mold and also provides the integral pigmented surface, resulting in a pumpkin that has a brighter orange color than if the pigment were simply mixed into the foam. The color is also more durable than if the pigment were simply sprayed onto the pumpkin as a coating after its formation.
Another feature of these improved pumpkins 10 are that they have fire retardant additives added to the foam. The fire retardant may be added to one of the foam components by the foam manufacturer, or it may be added to the foam at the point of the foam use, during the pumpkin manufacturing process. The fire retardant may be a liquid fire retardant or fire retardant particles. In a particular embodiment, it has been found that providing about 1 to about 20% flame retardant in the foam provides a pumpkin that, if subjected to flames and fire, will self-extinguish in about one minute or less. Thus, although the pumpkins are intended for use with artificial lights, if the pumpkin does catch fire due to exposure to an open flame, it should not ignite, spark, or become a dangerous fire ball. Instead, the outside becomes a flame barrier, and the fire is contained inside the pumpkin until it smolders out. It is understood that it is possible to add from about 1 to about 5%, from about 3 to about 10%, or from about 5 to about 20% flame retardant to the foam. The higher the percentage of flame retardant added, the higher the manufacturing cost of the pumpkins may become. One specific percentage that has been found to provide a good balance is 5% flame retardant. In a specific embodiment, the flame retardant added is Levangard Antiblaze TMCP or TCPP manufactured by the Lanxess Corporation, which may also be referred to as Tris (2-chloroisopropyl) phosphate. This component may be provided in increments of about 5% to about 20%, based on fire retardancy requirements.
The disclosure will now turn to specific methods of manufacture for the carvable pumpkins 10. A two-part mold is generally formed as a silicone skin mold, which is flexible. As such, in order to form the completed pumpkin, the mold is supported by a rigid box 21. The box 21 forms a rigid outer support during the formation of the pumpkin. An example is shown in
Applied to the inside of the mold 22 is a pigmented release layer 26. This forms a pigmented mold release. Pigment composition 26 is applied to the silicone mold 22 prior to insertion of the foam 28, which allows the pigment to fuse with the foam so that it is integrally formed with the foam 28. Once the pigment has been applied to the layer 22 to provide a pigmented mold release, the foam 28 is then applied into the mold. As shown in
In the prior art manufacturing method, the foam was sprayed inside the mold, and as the polyurethane foam spraying began, the nozzle would either rotate, or the mold would revolve around the nozzle so that polyurethane foam material covers the inside of mold completely to the desired depth. In other words, the nozzle had to spray the foam at a consistent depth. It also had to be shaped to allow more material to exit near the “equator” than near the poles, to compensate for the greater surface area around the “equator.” Past nozzles were also designed to spray slightly more material towards the top and bottom hemispheres of the mold to compensate for gravity.
By contrast, the new manufacturing method described herein provides a plug 30 that is used to be pressed against the layer of foam 28 in order to create a corresponding, desired inner shape of the pumpkin. The plug 30 is generally provided in a shape that corresponds to the bulges and undulations of the pumpkin retainer mold 24. It is designed to cause the foam that forms the inner surface of the pumpkin to take the shape of the plug 30. Creating the pumpkin mold this way alleviates the need to ensure that the foam is sprayed in a perfectly even manner, and it also alleviates the need to spin the pumpkin mold to distribute the foam along the inner surface of the mold. Instead, the plug 30 creates the desired undulations and thickness. The thickness of the dimension between the outer surface 14 and inner surface 12 of the pumpkin 10 can be changed, depending upon desired parameters. Changing the dimension is accomplished by changing the distance that the plug 30 is positioned from the mold 24. The plug 30 is a rigid, solid piece, and it may have a circular or oblong or any other shape that allows it to form the desired inner surface shape. As the foam expands, it flows around the plug 30, creating a consistent and controllable thickness of the pumpkin skin. This provides a pumpkin that is easily and consistently carvable, without uneven patches of foam in various areas. This method allows the thickness “T” between the inner and outer surface to be consistently formed and controlled, and made substantially uniform where desired.
Once the foam has been sprayed into the mold, the mold may be positioned on a conveyor, such that the conveyor moves the mold in the box away from the foam application station, to a clamp or press. Once the plug 30 has been positioned and has shaped the foam, the mold may be moved to a station that opens the mold and removes the formed foam from the mold, facilitated by the pigmented release layer. A separate painting step in not required due to the pigmented mold release. The stem 18 at the top of the pumpkin may be formed as a part of this process (with a different color applied to the mold release layer to provide a darker stem if desired), or it may be secured to the pumpkin in a separate step.
A flowchart of these steps is provided in
Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.
