Patent Application
20080020156
1. Field of the Invention
The present invention relates to a disposable container, methods of making the disposable container and machines and devices that can be used in the method and/or to make the disposable container. More particularly, the present invention relates to a container made of expandable thermoplastic resin beads with a label sheet disposed about the outer surfaces of the sidewall of the container. The container can be used for holding hot or cold liquids, such as beverages, or foods such as instant noodles, soups, fried chicken, and the like.
2. Background Art
The manufacture of molded articles, such as containers, for example cups, bowls, and the like from expanded thermoplastic particles is well known. The most commonly used thermoplastic particles are expandable polystyrene particles known as EPS. Typically, polystyrene beads are impregnated with a blowing agent, which boils below the softening point of the polystyrene and causes the impregnated beads to expand when they are heated.
The formation of molded articles from impregnated polystyrene beads is generally done in two steps. First, the impregnated polystyrene beads are pre-expanded to a density of from about 0.5 to 12 pounds per cubic foot or 5 to 150 grams per liter. Second, the pre-expanded beads are heated in a closed mold to further expand the pre-expanded beads to form a fused article having the shape of the mold.
The expandable polystyrene particles used to make foam containers are generally prepared by an aqueous suspension polymerization process, which results in beads that can be screened to relatively precise bead sizes. Typically, bead diameters are within the range of from about 0.008 to about 0.02 inch (about 0.2 to about 0.5 mm). Occasionally, cups are made from particles having bead diameters as high as 0.03 inches.
It is desirable to provide containers with thin walls that provide adequate insulating and structural properties and that contain high quality printed graphics on the outside surfaces of the container.
One method of obtaining printed graphics on the outside surfaces of a container is by molding the container and then printing on the outside surface of the container. However, this approach typically results in lower print quality and does not convey the desired commercial image.
Another method that has been employed is to pre-print labels that are applied to the outside surfaces of a container after molding. As an example, U.S. Patent Application Publication No. 2006/005917 A1 discloses a method and apparatus for producing labeled, plastic foam containers, such as labeled EPS cups that includes using a heated secondary mold to thermally bond a label to a plastic cup. Although high quality graphics can be applied to containers using these methods, labeling consistency, due to the many mechanical steps involved is a problem. Also, the seam formed where the ends of the label meet often leaves a gap between the ends of the label sheet, where the container surface can be seen, the label can be poorly aligned vertically overlapping the container rim or base, and/or the label ends overlap forming a raised seam that can be aesthetically unattractive, can lead to inefficient cup stacking, as well as providing a site where labels can be peeled from the container surface.
Attempts to solve the above described problems have been attempted through in-mold labeling techniques. As an example, WO 01/85420 discloses a method and apparatus for molding an expanded plastic container having a label material affixed to an external wall of the container during the molding cycle. In this method, a label to be affixed to a molded container is transferred by a plunger having a vacuum pick-up head from a stack of flat labels to a dummy male core and is wrapped about the dummy core. The latter is mounted on a carriage, which is reciprocal between the label pick-up station and a vertically oriented molding station having a molding tool for molding expanded plastic material. When the dummy core enters the female mold part, the label carried by the core is transferred to and retained on the wall of the female mold part. Particular problems with this method include inconsistent label placement and molding consistency as the many mechanical steps and vertical orientation cause shifting of the machine parts and label. These problems result in a large amount of waste, i.e., containers that are molded and/or labeled improperly and cannot be used.
Additionally, in some instances, improper label placement can result in containers that leak.
There is an unmet need in the art for methods and equipment to produce smooth surfaced consistently labeled containers that can be manufactured with low waste at commercial scale and overcome the above-described problems.
The present invention is directed to a labeled expanded resin container that includes pre-expanded resin beads molded in a shape having a sidewall with an outer surface and a base; and a label formed from a label material capable of maintaining an electrostatic charge disposed over at least a portion of the outer surface of the sidewall of the container. The container has a rim strength that is at least 50% greater than the rim strength of a container that does not contain a label, where the containers are otherwise made using the same equipment. After a liquid at 50° F. (10° C.) is placed in the container and the container is exposed to conditions of 86° F. (30° C.) and 60% relative humidity for 30 minutes, less than 2 ml of moisture condenses on the outer surface of the container.
Other than in the operating examples or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, etc. used in the specification and claims are to be understood as modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties, which the present invention desires to obtain. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10; that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.
In order to form a more complete understanding of the invention the following description should be taken in connection with the accompanying drawing figures where like reference characters identify like parts throughout.
For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.
As used herein, the term “partial conical shape” refers to a shape having a first planer base that is smaller than a second planar base with a surface that tapers from the second planar base to the first planar base.
As used herein, the term “mandrel” refers to a device that has a shape similar to the male portion of a two-part mold, which can be a partial conical shape, to which a label can be fixed for transfer to the female portion of a two-part mold.
As used herein, the term “non-conducting material” refers to a material that does not readily transmit electricity by conduction.
As used herein, the term “not deformable” means a material or article that does not change its shape when reasonable stress is applied thereto at ambient or processing conditions.
As used herein, the term “not hygroscopic” refers to a property of a material in that the material does not readily absorb, adsorb, or otherwise collect or accumulate moisture at ambient conditions or under the operating conditions of the equipment described herein.
As used herein, the term “surface resistivity” refers to the resistance to the flow of electrical current over the surface of a material as can be determined, as a non-limiting example, by ASTM D257, where the resistance to an electrical current is measured by electrodes on the same surface of a material, typically reported as Ohms/sq. Surface resistivity describes the ratio of DC voltage drop per unit length to the surface current per unit width.
Suitable instruments for measuring surface resistivity include, but are not limited to the Model ST-3 Work Surface Tester available from SIMCO Japan, Inc., Kobe, Japan and Model 19670 Surface Reistivity Meter available from Charles Water Co., Canton, Mass.
As used herein the term “rail” refers to a bar, rod, track, or other surface along which a wheel, collar, sleeve, or other device can move along to move a car from one position to another.
As used herein the term “car” refers to a housing, cabinet, or other structure to which the cavity parts described below are attached to or which contains cavity parts and includes one or more wheels, collars, sleeves, or other devices to enable the car to move along a rail from one position to another.
As used herein, the terms “(meth)acrylic” and “(meth)acrylate” are meant to include both acrylic and methacrylic acid derivatives, such as the corresponding alkyl esters often referred to as acrylates and (meth)acrylates, which the term “(meth)acrylate” is meant to encompass.
As used herein, the term “polymer” is meant to encompass, without limitation, homopolymers, copolymers, graft copolymers, and blends and combinations thereof.
Unless otherwise specified, all molecular weight values are determined using gel permeation chromatography (GPC) using appropriate polystyrene standards. Unless otherwise indicated, the molecular weight values indicated herein are weight average molecular weights (Mw).
As used herein, the term “expandable resin beads” refers to a polymeric material in particulate or bead form that is impregnated with a blowing agent such that when the particulates and/or beads are placed in a mold or expansion device and heat is applied thereto, evaporation of the blowing agent (as described below) effects the formation of a cellular structure and/or an expanding cellular structure in the particulates and/or beads. When expanded in a mold, the outer surfaces of the particulates and/or beads fuse together to form a continuous mass of polymeric material conforming to the shape of the mold.
As used herein, the term “pre-expanded resin beads” refers to an expandable resin beads that have been expanded, but not to their maximum expansion factor and whose outer surfaces have not fused. As used herein, the term “expansion factor” refers to the volume a given weight of resin bead occupies, typically expressed as cc/g. Pre-expanded resin beads can be further expanded in a mold where the outer surfaces of the pre-expanded resin beads fuse together to form a continuous mass of polymeric material conforming to the shape of the mold.
The present invention includes the opening and closing of valves and gates, the movement of cars along rails to specified positions, and the coordination and timing of various steps in the inventive methods and devices. In all instances, the various steps, controls and placements can be done manually, but will often be accomplished through the use of preprogrammed microprocessors and/or computers interfacing with appropriate sensors, actuators, relays, feedback loops, motors, pneumatic devices, servos, resolvers and the like as are known in the art.
The present invention provides for the molding of an expanded plastic container, which can be a thin wall product, formed from expanded plastic materials. The invention also provides containers that are labeled consistently and have a smooth surface finish, and full cover printing to a level and quality not possible with prior expanded plastic containers.
As used herein, “labeled consistently” means that the number of labeled containers produced by the methods and devices disclosed herein will meet commercial requirements. The absolute number will depend on particular commercial requirements and can be less than 5%, in some cases less than 4%, in other cases less than 3%, in some instances less than 2% and in other instances less than 1% waste due to mislabeled containers, i.e., containers where the label has an unintentional gap between its ends or the label overlaps the base or rim of the container.
As noted, the present invention enables the reproducible production of a labeled container in which a printed label sheet is adhered to the external surface of the container during the molding process. In an embodiment of the invention, the label sheet can have a heat activated adhesive layer on the side in contact with the container and is positioned in the mold cavity directly against the wall of the female portion defining the external wall of the container, whereby the label sheet is laminated with the expanded plastic material and with the external wall of the container during the molding process.
Of particular note, the labeled container provided by the invention presents a smooth circumferential surface. By “smooth circumferential surface” is meant that the label on the outer wall of the labeled container has a nearly imperceptible seam where the two ends of the label come together and/or overlap. In prior art methods, such as after mold labeling, the two ends of the label often come together to form a raised seam. In other situations, attempts are made to perfectly match the edges of the label, but often raised seams or gaps between the edges result. The present invention overcomes these problems as any overlap of the label edges is embedded within the wall of the container and is less perceptible from the exterior. Thus, although a seam line may, in some instance, be perceptible as an edge of a label sheet with containers made according to the invention, the container wall surface across the seam line is smooth to the touch. In an embodiment of the invention, if the seam line has any perceptible depth when viewed from the outside wall of the labeled container, the seam line depth is at least 1 μm, in some cases at least 0.5 μm, in other cases at least 0.25 μm, in some instances at least 0.1 μm, and in other instances at least 0.05 μm, and is not greater than 2 μm. In this embodiment, if a seam line exists, the seam line depth can be any value or vary between any of the values recited above.
According to the invention, an expanded plastic container is advantageously molded with the mouth of the container directed in a horizontal orientation so as to minimize or eliminate the force of gravity from causing the label sheet to shift between placement and molding, resulting in a mislabeled container (one form of waste). Steam for cooking the raw plastic material is introduced or injected into the male and/or female portions of the mold cavities, which can be alternately flushed with steam to heat the mold during preheating and cooking and with cooling liquid during cooling, which can be provided adjacent the inside and outside of the mold cavity. Also, a portion of the steam can be redirected and utilized to flush the cavities themselves during cooking.
An embodiment of the invention, a method of making a labeled expanded resin container, is outlined in
In an embodiment of the invention, as shown in
In another embodiment of the invention, the gap or space between the label sheet on mandrel 12 and the inner wall of female portion 16 when mandrel 12 is inserted in female portion 16 is small. In this embodiment, the gap can be at least 0.01, in some cases at least 0.05 and in other cases at least 0.1 mm and can be up to 5, in some cases up to 3, in other cases up to 2, and in some instances up to 1 mm. A smaller gap between mandrel 12 and the inner wall of female portion 16 provides for more precise placement of the label sheet in female portion 16. The gap or space between the label sheet on mandrel 12 and the inner wall of female portion 16 can be any value or range between any of the values recited above.
As shown in
In an embodiment of the invention, female portions 16 and male portions 20 of two-part mold 18 are adapted such that when the female portions 16 are in the removed position the male portions 20 and female portions 16 are spaced apart and not in contact with each other and such that when the male portions 20 are in the releasing position or extended position, the male portions are spaced apart and not in contact with the female portions 16.
Subsequently, male portion 20 of the two-part mold 18 and female portion 16 are brought in contact to form a mold cavity (
As can readily be envisioned by those skilled in the art, devices used to carry out the above-described method can be equipped with a plurality of two-part mold cavities 18 and a corresponding number of mandrels 12. The horizontal alignment of the two-part mold cavities and mandrel allow for more precise positioning of the label sheet 10 in female portion 16, resulting in less waste due to mislabeled containers, a significant advantage over the prior art.
The label sheet 10 is an important aspect of the invention, as it must be capable of maintaining an electrostatic charge in order to effect transfer and electrostatic adhesion to the inner wall of female portion 16. As such, label sheet 10 includes
In an embodiment of the invention, the label sheet can be made from flexible sheet material, optionally printed on its outside or inside surface with advertising or other matter. It is of such dimensions and configuration as to be foldable about itself into a partial conical shape matching the side wall of the container and to extend about the circumference of the container for the full height of the side wall of the container.
The label sheet, substrate or material is capable of maintaining a surface electrostatic charge. As such, the surface resistivity of the label sheet, substrate or material is greater than 1010 ω/sq, in some cases greater than 1011 ω/sq, in other cases greater than 1012 ω/sq, in some instances greater than 1013 ω/sq, and in other instances greater than 1014 ω/sq. The greater the surface resistivity of the label sheet, substrate or material, the stronger and longer the electrostatic attraction between the label sheet and inner wall of female portion 16 will be.
In an embodiment of the invention, the substrate of label sheet 10 includes one or more materials selected from one or more thermoplastic resins, cellulose based paper, and synthetic paper.
Any suitable thermoplastic resin can be used. Suitable thermoplastic resins include, but are not limited to one or more selected from polyolefinic resins, ethylene-acrylic acid copolymers, ethylene-C1-C12 alkyl (meth)acrylate ester copolymers, metal salts of ethylene-methacrylic acid copolymers, poly(4-methyl-1-pentene), polyethylene terephthalate resins, polyvinyl chloride resins, polyamide resins, ABS resins, and combinations thereof.
Any suitable polyolefinic resin can be used. Suitable polyolefinic resins include, but are not limited to propylene resins, high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, ethylene-cyclic olefin copolymers, copolymers of propylene and one or more α-olefins, and combinations thereof.
Suitable synthetic papers that can be used in the invention include, without limitation, resin-coated paper, polyesters, microporous materials such as polyethylene polymer-containing material sold by PPG Industries, Inc., Pittsburgh, Pa. under the trade name of TESLIN®, a non-limiting example of which are those disclosed in U.S. Pat. No. 6,066,594, the relevant portions of which are incorporated herein by reference, TYVEK® synthetic paper available from E.I. DuPont de Nemours and Company, Wilmington, Del., OPPALYTE® films available from Mobil Oil Corp., New York, N.Y., other composite films listed in U.S. Pat. No. 5,244,861, the relevant portions of which are incorporated herein by reference, melt-extrusion-coated paper, and biaxially oriented support laminates, such as those described in U.S. Pat. Nos. 5,853,965; 5,866,282; 5,874,205; 5,888,643; 5,888,681; 5,888,683; and 5,888,714, the relevant portions of which are incorporated herein by reference.
In an embodiment of the invention, the substrate has a melting point of at least 120° C., in some cases greater than 130° C., in other cases greater than 135° C. and in some instances greater than 140° C. The melting point of the substrate is advantageously greater than the processing temperatures during molding.
The thickness of the substrate can vary based on factors such as the type of label material, the amount of structural support desired from the label sheet, and the quality of the graphics to be printed on the label sheet. As such the substrate can be at least 10 μm, in some cases at least 25 μm and in other cases at least 50 μm thick and can be up to 1,500 μm, in some cases up to 1,250 μm, in other cases up to 1,000 μm, in some instances up to 750 μm and in other instances up to 500 μm thick. The thickness of the substrate can be any value or range between any of the values recited above.
Any suitable heat sensitive adhesive can be used in the invention. Suitable heat sensitive adhesives include, but are not limited to ethylene-vinyl acetate copolymers, polyolefin resins, polyester resins, polyester-amide resins, polyamide resins, thermoplastic elastomers, acrylic resins, cellulosic resins, print lacquers and combinations thereof.
In an embodiment of the invention, a first end of a label overlaps with a second end of a label to create a seam line as described above. In this embodiment, a heat sensitive adhesive is only applied to at least a portion of a bottom surface of only the overlap portion of the first end such that the heat sensitive adhesive contacts at least a portion of a top surface of the overlap portion of the second end.
The label sheets used in the present invention are typically used to provide high quality graphics to the outside surface of the container. As such, the label sheets can include a coating and/or printing ink on a surface of the label. If the label is printed or coated on a surface in contact with the inner wall of female portion 16, the components of the coating or printing ink advantageously have a melting and/or softening point of at least 120° C., in some cases greater than 130° C., in other cases greater than 135° C. and in some instances greater than 140° C. When the melting and/or softening point of the components of the coating or printing ink are greater than the processing temperatures during molding, sticking of the labeled container to the inner wall of the female portion can be avoided.
When the label sheet is printed or coated on a side that is not in contact with the inner wall of female portion 16, any suitable printing ink or coating can be used. Typically, the substrate is clear and the printing or coating can be seen through the substrate.
In an embodiment of the invention, when printing or coatings are placed on a side that is not in contact with the inner wall of female portion 16, the printing or coating is a mirror image so that the desired image is viewed through the label sheet on the labeled container.
In an embodiment of the invention, the label sheet and any ink, adhesive or other coating on the label sheet are suitable for direct and/or indirect food contact and comply with one or more of Section 201 of the U.S. Federal Food, Drug and Cosmetic Act, U.S. 21 Code of Federal Regulations (2005), EU Plastics Directive, 2002/72/EC, CoE Resolution on paper and board, Resolution AP (2002) 1, or EC Superdirective on Food Contact Materials.
Mandrel 12 is used to transfer and position label sheet 10 in female portion 16. In some embodiments of the invention, as shown in
Lengthwise suction holes 58 desirably secure and hold a label sheet against mandrel surface 54. Circumferential suction holes 59 desirably hold a label sheet in a desired position and orientation on mandrel surface 54 to ensure proper positioning when inserted onto the inner wall of a female portion and ultimately, proper label placement on the labeled containers provided according to the invention. Thus the present method and device are able to minimize waste resulting from mislabeled containers.
In other embodiments of the invention, as shown in
Label adhering suction holes 70 desirably secure and hold a label sheet against mandrel surface 54 when it is first placed on mandrel 12. Label wrapping suction holes 72 desirably hold a label sheet in a desired position and orientation on mandrel surface 54 as the label is wrapped around mandrel 12. First row 74 and second row 76 of overlap suction holes 78 and 80 respectively ensure proper positioning when wrapping is completed. Suction holes 70, 72, 78 and 80 hold a label in a desired position and orientation while it is inserted into a mold and transferred onto the inner wall of a female portion and ultimately, proper label placement on the labeled containers provided according to the invention. Thus the present method and device are able to minimize waste resulting from mislabeled containers. In many embodiments of the invention, D1 and D2 represent diameters of first base 50 and second base 52 respectively, which can be circular in shape.
In an embodiment of the invention, the dimension D1 can be at least 1, in some cases at least 1.5 and in other cases at least 2 cm and can be up to 12, in some cases up to 10, and in other cases up to 8 cm. The dimension D1 will depend on the dimensions of the inner surface of female portion and the desired labeled container. The dimension D1 can be any value or range between any of the values recited above.
In another embodiment of the invention, the dimension D2 can be at least 1.5, in some cases at least 2 and in other cases at least 2.5 cm and can be up to 20, in some cases up to 15, and in other cases up to 10 cm. The dimension D2 will depend on the dimensions of the inner surface of female portion, the desired labeled container and will be larger than the dimension D2. The dimension D2 can be any value or range between any of the values recited above.
Any suitable non-conducting material can be used for mandrel surface 54, so long as it is able to electrically insulate and prevent short-circuiting of charging pins 56. Suitable materials include, but are not limited to one or more materials selected from fluoropolymers, homopolymers and copolymers of fluoromonomers, homopolymers and copolymers of olefins, homopolymers and copolymers of vinyl aromatic monomers, polyesters, polyamides, polyester-amides, homopolymers and copolymers of vinyl chloride, polycarbonates, polyoxymethylene, acetal polyoxymethylene, polysulfones, ceramics, wood, glass, elastomeric polymers, combinations thereof and metals coated with one or more of the materials listed above.
Non-limiting examples of suitable fluoropolymers and homopolymers and copolymers of fluoromonomers include homopolymers and copolymers containing one or more monomers selected from chlorotrifluoroethylene, tetrafluoroethylene, trifluoroethylene, difluoro-ethylene, hexafluoropropylene, vinyl fluoride and C1-C12 alkyl (meth)acrylates containing from 1 to 20, in some cases 1 to 15, and in other cases from 1 to 10 fluorine atoms, depending on the number of carbon atoms in the alkyl chain. Non-limiting examples of suitable fluoropolymers include poly(vinylidene fluoride), poly(vinyl fluoride), poly(chlorotrifluoroethylene), poly(tetrafluoroethylene), poly(trifluoroethylene), the LUMIFLON® polymers available from Asahi Glass Company, Ltd., Tokyo, Japan. KYNAR® available from Atofina Chemicals, Inc., Philadelphia, Pa., HYLAR® available from Ausimont, an affiliate of the Montedison group, Milan, Italy, the NAFION®, TEFZEL®, and TEFLON® available from E.I. DuPont de Nemours and Company, Wilmington, Del., POM-PTFE™ available from Kern GmbH, Grossmaischeid, Germany, and ARNITE® available from DSM IP Assets B.V, the Netherlands.
Mandrel surface 54 has an area sufficient to support a label during the label insertion process described herein. Mandrel surface 54 supports a label near first base 50, second base 52 and the space between the various suction holes and charging depressions as described above.
Charging pins 56 comprise a metal capable of conducting electricity and can contain, without limitation, copper, iron, silver, aluminum, tungsten, manganese, nickel, chromium, manganin, constantan, nichrome, and combinations thereof. Electricity is conveyed to charging pins 56, by way of power line 60.
In an embodiment of the invention shown in
Charging depressions 53 can have any suitable shape, but will usually have a shape that allows for adequate charge transfer from charging pins 56 to a label. As such, charging depressions 53 can have a circular, oval, elliptical, square, rectangular, triangular, pentagonal, hexagonal, heptagonal, octagonal, trapezoidal, parallelogram-like, or other suitable shape.
Charging depressions 53 extend a depth into mandrel surface 54 that allows for adequate charge transfer from charging pins 56 to a label. As such, charging depressions 53 can have a depth of at least about 0.04 inches (1 mm), in some cases at least about 0.1 inches (2.5 mm) and in other cases at least about 0.25 inches (6.4 mm) and can be up to about 2 inches (51 mm), in some cases up to about 1.75 inches (44.5 mm) and up to about 1.5 inches (38 mm). The depth of charging depressions 53 is determined based on the amount of charge desired and the characteristics of charging pins 56. The depth of charging depressions 53 can be any value or range between any of the values recited above.
The shape of charging depressions 53 formed in mandrel surface 54 can have an area of at least about 0.01 in2 (6.5 mm2), in some cases at least about 0.05 in2 in2 (32 mm2), and in other cases at least about 0.1 in (65 mm2) and can be up to about 4 in2 (2,581 mm2), in some cases up to about 2 in2 (1290 mm2) and in other cases up to about 1 in2 (645 mm2). The area of charging depressions 53 is determined based on the amount of charge desired and the characteristics of charging pins 56. The area of charging depressions 53 can be any value or range between any of the values recited above.
Referring to
Referring to
In embodiments of the invention, vacuum line 62 and suction holes 58 and 59 can be adapted to provide a “puff” of compressed air to effect transfer of a label from mandrel 12 to the inner wall of female portion 16. Similarly, vacuum channels 90, 92, 94 and 96 and suction holes 70, 72, 78 and 80 can be adapted to provide a “puff” of compressed air to effect transfer of a label from mandrel 12 to the inner wall of female portion 16.
In an embodiment of the invention, remover 14 can be attached to mandrel 12 (see
The vacuum can be applied, as a non-limiting example, by using a vacuum pump or a venturi attached to a compressed air line as is known in the art.
Mandrels have been used for in-mold labeling in injection molding operations as disclosed in U.S. Pat. No. 6,007,759. The disclosed injection molding mandrels include an electrically conducting layer consisting of a flexible foam material as an outer surface. Using such an outer surface on the present mandrel is undesirable as it leads to inconsistent and poor label placement on the inner wall of the female portion because the foam material cannot be machined to exact measurements to provide for tight tolerances and clearances as the present mandrel can. Additionally, the thickness of the foam material can decrease with use due to wear, leading to further inconsistent label placement.
As indicated above, mandrel 12 is used to transfer and position a label sheet 10 to the inner wall of female portion 16. Once label sheet 10 is positioned, female portion 16 and male portion 20 of two-part mold 18 can be utilized to make labeled container 24. Thus, two-part mold tool 18 for molding the expanded plastic container includes a male portion 20 and a female portion 16 which are assembled to form a mold cavity defining the container having, at least one cavity for heating and/or cooling fluid in at least one of the male and/or female portions adjacent the mold cavity and extending adjacent at least that part of the cavity defining the side wall(s) of the container, conduit means for supplying steam to the heating/cooling cavity, and a passageway means through which steam is injected into the mold cavity.
In the present invention, labeled container 24 is molded in a horizontal orientation with its mouth and base in a plane and steam for cooking plastic material is injected at least at the base end (male portion) of the mold adjacent the base of the container. The two-part mold tool 18 can include a male portion 20 that includes a core section and an outer shell fitted over the core section so as to provide a heating/cooling cavity within the outer shell. The outer surface of the shell molds the internal surface of the container and the heating/cooling cavity can be substantially coextensive with the shell. The male portion 20 cooperates with a female portion 16, with label sheet 10 positioned along an inner wall, assembled over the male portion to define the mold cavity. The female portion 16 can include an inner female shell which molds the external wall of the container to the label sheet and a mold member fitted over the outside of the female shell so as to provide a heating/cooling cavity substantially coextensive with the female shell and about the outside of the mold cavity. Suitable conduits are arranged to supply flushing steam or cooling liquid to the heating/cooling cavities. One of the conduits is connectable, under control of a first valve means, to a passageways means communicating with the end of the mold cavity to permit steam to be injected into the mold to cook the molding material.
An embodiment of the mold cavity used in the present invention is shown in
The core section and outer shell of the male portion 112 can be secured together at an end of the mold tool by machine screws 116 and the inner female shell and a mold member of the female portion 114 can be secured together by machine screws 117. O-ring seals 138 can be disposed between the components of the mold parts, at appropriate positions, to seal the components together.
Extending centrally through the male portion 119 to a position adjacent the left end thereof is a central conduit 125 through which flushing steam for heating the mold during preheating or cooking or cooling liquid for cooling the mold is alternatively supplied to the inner cavity 121. Flushing steam or cooling liquid is delivered to the conduit 125 by a pipe 115 that can be coupled to the male portion by machine screws 113 and sealed to the conduit by an O-ring seal 111. Steam or liquid exits the cavity 121 through an annular outlet 126 adjacent the right end of the mold tool. At its left end, the conduit 125 is connected, through a valve port 127 to diametrically disposed passageways 128 communicating with the mold cavity 118 via an annular groove (not shown) in the outer surface of the outer shell 120. The valve port 127 can be controlled by a spring loaded valve member 130 disposed at the left end of the conduit 125 and actuated by a hollow valve rod 131 projecting through the conduit to a suitable pneumatic actuating mechanism. The valve member 130 has an axial passageway 132 connected to the hollow actuating rod 131 to permit compressed air to be supplied through the rod, the valve member and the passageways 128 into the mold cavity so as to assist in ejecting a molded container from the mold cavity 118 at the end of the molding cycle.
Flushing steam and cooling liquid are alternatively supplied to the outer heating/cooling cavity 124 via a port 135 in the top mold member 123, which port is connected to a suitable supply conduit (not shown). The steam and liquid exit from the cavity via an annular outlet 136 and annular manifold 137 adjacent the right end of the mold cavity.
Expandable and/or pre-expanded resin beads of a suitable molding material for the container as described below can be supplied to the mold cavity through a conduit (not shown) coupled to the top mold member 123 by a coupling unit (not shown) attached to the top mold member and connected to a funnel shaped port 140 in the inner female shell 122 which communicates with mold cavity 118. Delivery of expandable and/or pre-expanded resin beads to mold cavity 118 can be assisted by the supply of compressed air through an air nozzle (not shown) also coupled to port 140. Also, compressed air can be supplied to the nozzle when the female portion 114 and male portion 112 are separated at the end of a molding cycle in order to retain the molded container on male portion 112 preparatory to removal from the tool by remover 14.
In order to mold a container, the female portion 114 is assembled to the male portion 112, as shown in
At the end of the cook cycle, the valve member 127 is closed and cooling liquid is supplied, via the conduit 125 and port 135, to the heating/cooling cavities 121 and 124 in order to cool the mold tool and the molded container, whereafter the male portion 112 and female portion 114 are separated and compressed air is supplied through the hollow valve rod 131 and valve member 130 to the passageways 128 in order to blow air into the molded cup and facilitate ejection of the cup from the male portion 112.
Further embodiments of the mold cavity used in the present invention are shown in
The core section and outer shell of the male portion 152 can be secured together at an end of the mold tool by bolts 166 and the inner female shell and a mold member of the female portion 154 can be secured together by bolts 167. O-ring seals 168 can be disposed between the components of the mold parts, at appropriate positions, to seal the components together.
Extending centrally through the core section 169 of male portion 152 to a position adjacent the left end thereof is a central conduit 165 through which flushing steam for heating the mold during preheating or cooking or cooling liquid for cooling the mold is alternatively supplied to the inner cavity 161. Flushing steam or cooling liquid is delivered to the conduit 165 by a pipe 155 that can be coupled to the male portion by machine screws and sealed to the conduit by an O-ring seal 151. Steam or liquid exits the cavity 161 through an annular outlet 156 adjacent the right end of the mold tool. At its left end, the conduit 165 is connected, through a valve port 157 to diametrically disposed passageways 168 communicating with the mold cavity 158 via annular groove 168 in the left hand portion of the outer shell 160. In this embodiment, annular groove 168 is positioned between valve port 157 and base end 180 of mold cavity 158. The valve port 157 can be controlled by a spring loaded valve member 170 disposed at the left end of the conduit 165 and actuated by a hollow valve rod 171 projecting through the conduit to a suitable pneumatic actuating mechanism. The valve member 170 has an axial passageway (not shown) connected to the hollow valve or actuating rod 171 to permit steam to be supplied through the rod, the valve member and the cook lid 167 to provide additional heat to the mold cavity 158 during the molding cycle.
Flushing steam and cooling liquid are alternatively supplied to the outer heating/cooling cavity 164 via port 175 in the left end of female portion 154, which port 175 is connected to a suitable supply conduit (not shown). The steam and liquid exit from the cavity via an annular manifold 177 adjacent the right end of the mold cavity.
At the end of the molding cycle, compressed air can be supplied through passageway 190 in order to blow air into the molded cup and facilitate ejection of the cup from the male portion 152.
In an embodiment of the invention, heat, which can be supplied in the form of steam as indicated above, can be applied in a heat cycle in the female portion that is independent from heat applied in a heat cycle in the male portion.
Expandable and/or pre-expanded resin beads of a suitable molding material for the container as described below can be supplied to the mold cavity through a conduit (not shown) coupled to the left of female portion 154 by a coupling unit (not shown) attached to female portion 154 and connected to a funnel shaped port 180 in the inner female shell 162 which communicates with mold cavity 158. Delivery of expandable and/or pre-expanded resin beads to mold cavity 158 can be assisted by the supply of compressed air through an air nozzle (not shown) also coupled to port 180. Also, compressed air can be supplied to the nozzle when the female portion 154 and male portion 152 are separated at the end of a molding cycle in order to retain the molded container on male portion 152 preparatory to removal from the tool by remover 14.
In order to mold a container, the female portion 154 is assembled to the male portion 152, as shown in
At the end of the cook cycle, the valve member 157 is closed and cooling liquid is supplied, via the conduit 155 and the port, to the heating/cooling cavities 161 and 164 in order to cool the mold tool and the molded container, whereafter the male portion 152 and female portion 154 are separated and compressed air is supplied through the hollow valve rod 171 and valve member 170 to the passageways 168 in order to blow air into the molded cup and facilitate ejection of the cup from the male portion 152.
In an embodiment of the invention, heat, which can be supplied in the form of steam as indicated above, can be applied in a heat cycle in the female portion that is independent from heat applied in a heat cycle in the male portion.
Additional embodiments of the invention provide coordination between the positioning of male portion 20, female portion 16 and mandrel 12/remover 14 and the molding cycle described above. When male portion 20 and female portion 16 are joined to form mold 18, as shown in
Following the dwell period, a cook period can be performed, whereby steam enters the mold cavity as described above. The cook period can be at least 5, in some cases at least 7 and in other cases at least 10 seconds and can be up to 60, in some cases up to 45 and in other cases up to 30 seconds and can be any length of time or range between any of the lengths of time described above.
Following the cook period, a cooling period can be performed, whereby cooling water is flushed through female portion 16 and male portion 20 as described above. The cooling period can be at least 5, in some cases at least 10 and in other cases at least 15 seconds and can be up to 60, in some cases up to 45 and in other cases up to 30 seconds and can be any length of time or range between any of the lengths of time described above.
Cooling water can continue to flow through female portion 16 and male portion 20 while the steps described in
Labeled container 24 typically then contains molded expandable resin beads or pre-expanded resin beads and has a density of at least 0.5, in some cases at least 1, in other cases at least 1.5, and in some instances at least 2lb./ft.3 and can be up to 12, in some cases up to 10, and in other cases up to 8 lb./ft.3. The density of the molded expandable resin beads or pre-expanded resin beads can be any value or range between any of the values recited above.
Generally, the expandable resin beads are prepared by dispersing a monomer mixture in an aqueous system; polymerizing the monomer mixture in the presence of a free radical polymerization initiator to form a dispersion of resin beads; screening the resin beads to remove beads with undesired dimensions; and impregnating the resin beads with a blowing agent.
Any suitable expandable resin beads or pre-expanded resin beads can be used in the invention. Suitable resin beads include those with dimensions that allow the expandable and/or pre-expanded beads to be fed to the two-part mold as described herein without clogging or obstructing the feed channels in the mold and are able to expand and fuse together to form a molded container as described herein. Suitable expandable resin beads, include but are not limited to, those that contain homopolymers of vinyl aromatic monomers; copolymers of at least one vinyl aromatic monomer with one or more of divinylbenzene, conjugated dienes, alkyl (meth)acrylates, (meth)acrylonitrile, olefins, and/or maleic anhydride; polyolefins; polycarbonates; polyesters; polyamides; natural rubbers; synthetic rubbers; and combinations thereof.
Suitable vinyl aromatic monomers include, but are not limited to, styrene, isopropylstyrene, alpha-methylstyrene, nuclear methylstyrenes, chlorostyrene, tert-butylstyrene. In an embodiment of the invention, the vinyl aromatic monomers can be copolymerized with one or more other monomers, non-limiting examples being divinylbenzene, conjugated dienes (non-limiting examples being butadiene, isoprene, 1,3- and 2,4-hexadiene), alkyl methacrylates, alkyl acrylates, acrylonitrile, and maleic anhydride, where the vinyl aromatic monomer is present in at least 50% by weight of the copolymer. In many embodiments of the invention, styrenic polymers are used, particularly polystyrene, however, other suitable polymers can be used, such as polyolefins (e.g. polyethylene, polypropylene), polycarbonates, polyphenylene oxides, and mixtures thereof.
In a particular embodiment of the invention, the expandable resin beads include expandable polystyrene (EPS) particles.
In the present invention, the resin beads are formed via polymerization in a suspension process, from which essentially spherical resin beads are produced. These beads are useful as resin beads for making expanded polymer containers. However, polymers derived from solution and bulk polymerization techniques that are extruded and cut into particle sized resin bead sections of appropriate dimensions can also be used.
In an embodiment of the invention, expandable resin beads or pre-expanded resin beads containing any of the above-mentioned polymers have an average particle size of at least 10, in some situations at least 25, in some cases at least 50, in other cases at least 75, in some instances at least 100 and in other instances at least 150 μm. Also, the expandable resin beads or pre-expanded resin beads can have an average particle size of up to 600, in some instances up to
The number average particle size and size distribution of the expandable resin beads or pre-expanded resin beads can be determined using low angle light scattering, which can provide a weight average value. As a non-limiting example, a Model LA-910 Laser Diffraction Particle Size Analyzer available from Horiba Ltd., Kyoto, Japan can be used
In an embodiment of the invention, the polymers in the resin bead have a weight average molecular weight (Mw) of at least 25,000, in some cases at least 50,000, and in other cases at least 75,000 and the Mw can be up to 1,000,000, in some cases up to 750,000 and in other cases up to 500,000. The weight average molecular weight of the polymers in the resin bead can be any value or can range between any of the values recited above.
In an embodiment of the invention, after polymerization, the resin beads are isolated and dried and then suspended in an aqueous system. As used herein, “aqueous system” means a solution or mixture containing at least 50 wt. % water as the solution medium and/or continuous phase. Dispersing aids, nonionic surfactants and/or waxes can also be added to the aqueous system. When the resin beads are dispersed in the aqueous system, one or more blowing agents can be added.
The expandable thermoplastic particles or resin beads can optionally be impregnated using any conventional method with a suitable blowing agent. As a non-limiting example, the impregnation can be achieved by adding the blowing agent to the aqueous suspension during the polymerization of the polymer, or alternatively by re-suspending the particles or resin beads in an aqueous medium and then incorporating the blowing agent as taught in U.S. Pat. No. 2,983,692. Any gaseous material or material which will produce gases on heating can be used as the blowing agent. Conventional blowing agents include aliphatic hydrocarbons containing 4 to 6 carbon atoms in the molecule, such as butanes, pentanes, hexanes, and the halogenated hydrocarbons, e.g., CFC's and HCFC's, which boil at a temperature below the softening point of the polymer chosen. Mixtures of these aliphatic hydrocarbon blowing agents can also be used.
Alternatively, water can be blended with these aliphatic hydrocarbons blowing agents or water can be used as the sole blowing agent as taught in U.S. Pat. Nos. 6,127,439; 6,160,027; and 6,242,540 in these patents, water-retaining agents are used. The weight percentage of water for use as the blowing agent can range from 1 to 20%. The texts of U.S. Pat. Nos. 6,127,439, 6,160,027 and 6,242,540 are incorporated herein by reference.
In an embodiment of the invention, the blowing agent can include one or more selected from nitrogen, sulfur hexafluoride (SF6), argon, carbon dioxide, 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluoro-propane, difluoromethane (HFC-32), 1,1-difluoroethane (HFC-152a), pentafluoroethane (HFC-125), fluoroethane (HFC-161) and 1,1,1-trifluoroethane (HFC-143a), methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, cyclopentane, neopentane, hexane, azodicarbonamide, azodiisobutyro-nitrile, benzene-sulfonylhydrazide, 4,4-oxybenzene sulfonyl-semicarbazide, p-toluene sulfonyl semi-carbazide, barium azodicarboxylate, N,N′-dimethyl-N,N′-dinitro-soterephthalamide, trihydrazino triazine, mixtures of citric acid and sodium bicarbonate, and combinations thereof.
In an embodiment of the invention, the blowing agent can be present in the expandable resin beads or pre-expanded resin beads at a level of less than 14 wt %, in some situations less than 6 wt %, in some cases ranging from about 2 wt % to about 5 wt %, and in other cases ranging from about 2.5 wt % to about 3.5 wt % based on the weight of the resin bead.
Any suitable dispersing aid can be used in the present invention. Suitable dispersing aids prevent the resin beads from sticking together when dispersed in the aqueous system. Examples of suitable dispersing aids include, but are not limited to finely divided water-insoluble inorganic substances such as tricalcium phosphate, zinc oxide, bentonite, talc, kaolin, magnesium carbonate, aluminum oxide and the like as well as water-soluble polymers such as polyvinyl alcohol, alkyl aryl sulfonates, hydroxyethyl cellulose, polyacrylic acid, methyl cellulose, polyvinyl pyrrolidone, and the like, sodium linear alkyl benzene sulfonates, such as sodium dodecylbenzene-sulfonate, and combinations thereof. In an embodiment of the invention, the dispersing aid includes tricalcium phosphate together with a sodium linear alkylbenzene sulfonate. The amount of the dispersing aid necessary will vary depending on a number of factors but will generally be at least about 0.01, in some cases at least about 0.05, and in other cases at least about 0.1 and can be up to about 2, in some cases up to about 1, and in other cases up to about 0.75 parts by weight per 100 parts by weight of resin beads. The amount of the dispersing aid can be any value or can range between any of the values recited above.
One or more non-ionic surfactants can be included such as polyoxyalkylene derivatives of sorbitan fatty acid esters, such as C8 to C32 linear or branched with up to five units of unsaturation, non-limiting examples being oleates, stearates, monolaurates and monostearates, an ethylene oxide/propylene oxide block copolymer, or other non-ionic or anionic surface active agent can be added to the aqueous suspension if desired. In an embodiment of the invention, the amount of surfactant is at least 0.01, in some cases at least 0.05, and in other cases at least 0.1 and can be up to 2, in some cases up to 1, and in other cases up to 0.75 parts by weight per 100 parts by weight of resin beads. The amount of surfactant can be any value or can range between any of the values recited above. In an embodiment of the invention, the HLB of the above-mentioned polyoxyalkylene containing surfactants is at least 8, in some cases at least 10 and in other cases at least 12 and can be up to 22, in some cases up to 20 and in other cases at least 18. The HLB of the polyoxyalkylene containing surfactants can be any value or can range between any of the values recited above. The non-ionic surfactants can aid in the formation of fine cell structure in the expanded resin beads.
The waxes used in the present invention, at atmospheric pressure, are typically solid at 20° C. and below, in some cases 25° C. and below, and in other cases 30° C. and below, and are liquid at 125° C. and above, in some cases 150° C. and above, and in other cases 200° C. and above. The physical properties of the waxes used in the present invention are selected to aid in the formation of fine cell structure in the expanded resin beads.
In an embodiment of the invention, the waxes are selected from natural and/or synthetic waxes. As such, the waxes used in the present invention can be one or more materials selected from C10 to C32, in some instances C12 to C32, in some cases C14 to C32, and in other cases C16 to C32 linear, branched or cyclic alkyl, alkenyl, aryl, alkaryl, or aralkyl alcohols; C10 to C32, in some instances C12 to C32, in some cases C14 to C32, and in other cases C16 to C32 linear, branched or cyclic alkyl, alkenyl, aryl, alkaryl, or aralkyl carboxylic acids and/or their corresponding ammonium and metal salts or C1 to C32, in some instances C12 to C32, in some cases C14 to C32, and in other cases C16 to C32 linear, branched or cyclic alkyl, alkenyl, aryl, alkaryl, or aralkyl esters; C10 to C32, in some instances C12 to C32, in some cases C14 to C32, and in other cases C16 to C32 linear, branched or cyclic alkyl, alkenyl, aryl, alkaryl, or aralkyl hydrocarbons; polyethylene; polypropylene; polyester; polyether; and combinations thereof, so long as they meet a combination of liquid and solid temperatures as defined above.
The polyethylene, polypropylene, polyester, and polyether waxes can have a molecular weight (Mw) of from about 1,000 to about 100,000 so long as they meet a combination of liquid and solid temperatures as defined above.
In an embodiment of the invention, the amount of wax is at least 0.01, in some cases at least 0.05, and in other cases at least 0.1 and can be up to 2, in some cases up to 1, and in other cases up to 0.75 parts by weight per 100 parts by weight of expandable resin beads or pre-expanded resin beads. The amount of wax can be any value or can range between any of the values recited above.
The resin beads used in the invention are advantageously solid particles in the form of thermoplastic resin particles produced from suspension polymerization as indicated above. The polymer is formed as a slurry of finely divided particles in the aqueous suspension. The particles are recovered by washing and drying.
In an embodiment of the invention, the resulting resin beads can be screened to remove any resin beads with particle sizes that are too large. In many cases, resin beads having a particle size greater than 600 μm, in some cases greater than 500 μm and in other cases greater than 400 μm are removed by screening.
The impregnated resin beads can include an interpolymer of a polyolefin and in situ polymerized vinyl aromatic monomers and optionally other expandable polymers.
In embodiments of the invention, the interpolymer of a polyolefin and in situ polymerized vinyl aromatic monomers is one or more of those described in U.S. Pat. Nos. 3,959,189; 4,168,353; 4,303,756, 4,303,757 and 6,908,949, the relevant portions of which are herein incorporated by reference. A non-limiting example of such interpolymers that can be used in the present invention include those available under the trade name ARCEL®, available from NOVA Chemicals Inc., Pittsburgh, Pa. and PIOCELAN®, available from Sekisui Plastics Co., Ltd., Tokyo, Japan.
In embodiments of the invention, the impregnated resin beads are partially expanded or “pre-expanded” prior to being used in the molding equipment according to the invention. Thus, the resin beads can be pre-expanded to a bulk density of at least 0.5 lb/ft3 (0.008 g/cc), in some cases at least 1.25 lb/ft3 (0.02 g/cc), in other cases at least 1.5 lb/ft3 (0.024 g/cc), in some situations at least 1.75 lb/ft3 (0.028 g/cc), in some circumstances at least 2lb/ft3 (0.032 g/cc) in other circumstances at least 3lb/ft3 (0.048 g/cc) and in particular circumstances at least 3.25 lb/ft3 (0.052 g/cc) or 3.5 lb/ft3 (0.056 g/cc). When non-expanded resin beads are used higher bulk density beads can be used. As such, the bulk density can be as high as 40 lb/ft3 (0.64 g/cc). The bulk density of the pre-expanded resin beads can be any value or range between any of the values recited above.
The bulk density of the polymer particles, resin beads and/or prepuff particles is determined by weighing a known volume of polymer particles, beads and/or prepuff particles (aged 24 hours at ambient conditions).
The expansion step is conventionally carried out by heating the impregnated beads via any conventional heating medium, such as steam, hot air, hot water, or radiant heat. One generally accepted method for accomplishing the pre-expansion of impregnated thermoplastic particles is taught in U.S. Pat. No. 3,023,175, the relevant portions of which are incorporated herein by reference.
In many embodiments of the invention, the pre-expanded resin beads have an average particle size of at least 10, in some situations at least 25, in some cases at least 50, in other cases at least 75, in some instances at least 100 and in other instances at least 150 μm. Also, the pre-expanded resin beads can have an average particle size of up to 600, in some instances up to 550, in other instances up to 500, in some cases up to 450, in other cases up to 400, and in some situations up to 350 μm. The maximum average size of the pre-expanded resin beads will be limited by the dimensions of the two-part mold to allow for feeding of the expandable and/or pre-expanded resin beads into the mold as described herein. The pre-expanded resin beads can be screened to remove beads that are too large. The pre-expanded resin beads used in this embodiment can be any value or can range between any of the values recited above.
The present invention provides a device for producing labeled expanded resin containers that can be used according to the above-described method. The present device includes
The female portion and male portion are typically made of metals and/or metal alloys that are good thermal conducting materials. As such, they can contain, in alloy or in clad layers, materials selected from, without limitation, copper, iron, silver, aluminum, tungsten, manganese, nickel, bronze, chromium, manganin, constantan, nichrome, and combinations thereof. Additionally, it can be desirable to include a layer, which can encompass the inner wall of the female portion with a hard metal or alloy. The hard material provides a surface that can be cleaned without damaging the surface of the inner wall of the female portion. Damage to the inner wall can cause containers to stick to the female portion during molding leading to undesirable unscheduled machine downtime. The hard material can be selected, without limitation, from stainless steel, molybdenum, tungsten, tantalum, niobium, vanadium, and combinations and alloys thereof.
In embodiments of the invention and in order to provide label sheets for use in the invention, the present device includes one or more or a plurality of label sheet magazines and an equivalent number of suction plates adapted to transfer label sheets from a magazine to a mandrel. As such, the present device includes
The present device can also include positioning fingers attached to the suction plate arm. The positioning fingers are adapted to wrap a label sheet around a mandrel.
The device, according to the invention, can include any number of corresponding male portions and female portions of two-part molds and a corresponding number of mandrels and removers, collectively referred to as “cavity parts”. Not meaning to limit the scope of the invention in any way, the device according to the invention can have one cavity part, two cavity parts and so on up to, in some cases 24 cavity parts depending on the desired throughput of the device. In an embodiment of the invention, the device can have from 1 to 24, in some cases from 1 to 12, in other cases from 1 to 10, in some situations from 2 to 10, in other situations from 2 to 8, and in some instance from 4 to 8 cavity parts. The following embodiment of the invention for illustration purposes describes, without limitation, a device for making labeled containers according to the invention that has six cavity parts (
Also shown in
Suction plate 278 and labeling fingers 280 are attached to labeling arm 274 by way of support 284 and rotating bar 286, which is adapted to rotate, simultaneously placing suction plate 278 in the feeding position and labeling fingers 280 in a rest position (shown) or by rotating suction plate 278 away from mandrel car 211 such that suction plate 278 is in the pick up position and labeling fingers 280 are in a wrapping position, directly above a mandrel. In the pick up position, suction plate 278 can remove the top label sheet from label sheet stack 279.
In an embodiment of the invention shown in
Rotating magazine housing 200 can be attached to labeling arm 274 by way of machine screws that are affixed to pre-placed holes in labeling arm 274 and upper support arm 201, lower support arm 202. During operation, labels are removed from first label magazines 205 by suction plate 278 as described herein. While the labels in first label magazines 205 are in a feeding position and are being depleted, a new batch of labels are loaded onto second label magazines 206. When at least one label stack on first label magazines 205 is depleted, either completely or to a prescribed number of labels, rotating means 203 rotates second label magazines 206 about rotation shaft 204 into the feeding position and first label magazines 205 into a loading position.
In an embodiment of the invention, rotating means 203 can be, as non limiting examples, a pneumatic drive, a mechanical drive, a servo drive, an electric motor or can be done using an appropriate handle by hand. Mechanical stops can be placed on rotation shaft 204 or in rotating means 203 to ensure the reproducible location of magazines 205 and 206 at the loading and feeding positions. Alternatively, the stops can be achieved by setting the stroke distance on a pneumatic drive or actuator or prescribing the number of turns or angles in a servo drive.
In another embodiment of the invention, a sensor can be placed on any of magazines 205, 206, or 276 to determine when the stack of labels is too low. The sensor can be set to either trigger a signal (as non-limiting examples a flashing light or audible alarm) and/or to signal rotating means 203 to rotate magazines 205 and 206 about rotation shaft 204.
Referring to
As shown in
Mandrel rails 209 are attached to top first brace 291 and the top third brace and oriented perpendicular to mold cavity rails 304, which are attached to the bottom second brace and fourth bottom brace 297. Labeling arm 274 is attached to top fourth brace 296 and bottom top brace 297.
Device 290 is adapted for making labeled containers according to the invention and is shown in
A female mold cavity car 300, containing six female portions 306 of two-part molds 314, as described above, which rests on female movement housing 305 adapted to move along mold cavity rails 304. Movement of female mold cavity car 300 along mold cavity rails 304 can be effected using electric motors, pneumatic drives, mechanical drives, servo drives, or by hand. Female movement housing 305 can include one or more collars 302 that fit around at least a portion of mold cavity rails 304. Alternatively (and not shown), wheels adapted to move along mold cavity rails 304 can be used. Mechanical stops can be placed on mold cavity rails 304 to ensure the reproducible location of female mold cavity car 300 at the molding position and the removed position. Temporary or removable stops can be used for the transfer position. Alternatively, the stops can be achieved by setting the stroke distance on a pneumatic drive or actuator, or by prescribing the number of turns and/or angles on a servo drive. In
In an embodiment of the invention, the transfer position and molding position of the female mold cavity car can be the same location.
Referring to
Referring again to
A male mold cavity car 310, containing six male portions 320 of two-part molds 314, which are inserted in female portions, rest on male movement housing 316 adapted to move along mold cavity rails 304. Movement of male mold cavity car 310 along mold cavity rails 304 can be effected using electric motors, pneumatic drives, mechanical drives, servo drives, or by hand. Male movement housing 316 can include one or more collars 312 that fit around at least a portion of mold cavity rails 304. Alternatively (and not shown), wheels adapted to move along mold cavity rails 304 can be used. Permanent mechanical stops can be placed on mold cavity rails 304 to ensure the reproducible location of Male mold cavity car 310 at the molding position and the extended position. Temporary or removable stops can be used for the releasing position. Alternatively, the stops can be achieved by setting the stroke distance on a pneumatic drive or actuator or by prescribing the number of turns and/or angles on a servo drive. In
Referring to
While the mandrel car 211, female mold cavity car 300 and male mold cavity car 310 are in the positions shown in
From the positions shown in
Any suitable pneumatic drive, servo drive, or actuator can be used in the present invention. Suitable pneumatic drives include, without limitation, single-acting, single acting with spring return, and double acting pneumatic cylinders. Suitable servo drives that can be used in the invention include, without limitation, those available from include, Bosch Rexroth Corp., Hoffman Estates, Ill., and GE Fanuc Automation, Inc., Charlottesville, Va., which can include without limitation associated motors, amplifiers, power supplies, feedback units, and brakes. Suitable pneumatic drives or servo driven actuators that can be used in the invention include those available from Norgren Inc., Littleton, Colo.; Universal Fluid Power Pty Ltd., Moorooka, Queensland, Australia; SP Air Limited, Manchester, United Kingdom, Bosch RexRoth Corp., Bethlehem, Pa., Siemens AG, Munich, Germany, SMC Corp., Indianapolis, Ind., and Festo USA, Hauppauge, N.Y.
The device according to the invention can be used in a method of making the present labeled containers. The method includes:
In an embodiment of this method, the step of applying a label sheet to an inner wall of each of one or more female portions of the two-part mold can be performed by:
In a further embodiment of the invention, the label material is capable of maintaining a surface electrostatic charge as described above. In a particular aspect of this embodiment, the surface resistivity of the label material is greater than 1010 ω/sq.
Another embodiment of the invention includes wrapping the label sheet around the mandrel using positioning fingers attached to the suction plate arm after transferring the label sheet from the suction plate to the mandrel.
In a particular embodiment of the present method, the mandrel is free floating when positioned in a female portion as described above.
In many embodiments of the invention, the male portions are horizontally positioned in the female portions of the two-part mold to form mold cavities by
In the present method, the female and male portions of the two-part mold are adapted such that when the female portions are in the removed position the male and female portions are spaced apart and not in contact with each other and such that when the male portions are in the releasing position or extended position, the male portions are spaced apart and not in contact with the female portions.
In an embodiment of the invention, the expandable resin beads or pre-expanded resin beads are added to the mold cavity by way of one or more feed channels in the female portion, where a valve is positioned at an end of the feed channels adapted to close and seal the feed channel from the mold cavities during expansion and fusion of the resin beads.
In another embodiment of the invention, the heat applied to the mold cavity can be independently controlled in the male portion and female portion. Thus, the applying heat step can include applying a heat cycle in the female portion that is independent from applying a heat cycle in the male portion.
In certain aspects of this embodiment, the method can include preheating the mold cavities by flushing steam cavities adjacent the outside of the mold cavities within the female portions with steam. This step can be followed by applying steam to the mold cavity from the male portion after preheating.
In other aspects of this embodiment, the method can include preheating the mold cavities by flushing steam cavities adjacent the outside of the mold cavities within the male portions with steam. This step can be followed by applying steam to the mold cavity from the male portion after preheating.
In additional aspects of this embodiment, the method can include preheating the mold cavities by flushing steam cavities adjacent the outside of the mold cavities within the male portions with steam and flushing steam cavities adjacent the outside of the mold cavities within the female portions with steam. This step can be followed by applying steam to the mold cavity from the male portion after preheating.
In embodiments of the invention, the labeled containers can be removed from the mold cavities after cooling by
In the present method, the time required for completing the steps from applying the label sheet to removing the labeled container can be completed in less than 60, in some cases less than 45 and in other cases less than 30 seconds.
The devices and methods described above provide a labeled expanded resin container that includes:
expandable resin beads or pre-expanded resin beads, as described above, molded in a shape having a sidewall with an outer surface and a base; and
a label formed from a label material capable of maintaining an electrostatic charge disposed over at least a portion of the outer surface of the sidewall of the container.
As indicated above, the present container has a label sheet that is laminated to the expanded plastic material and with the external wall of the container during the molding process. A key feature of the present container is that the labeled external wall presents a smooth circumferential surface.
The label includes an electrically insulating substrate, as described above, having a first surface and a second surface; a heat sensitive adhesive, as described above, disposed over at least a portion of the first surface, and optionally a coating and/or printing ink disposed over at least a portion of a surface of the label sheet.
As shown in
In an embodiment of the invention, first end 412 overlaps second end 414 to create a seam described above. In this embodiment, a heat sensitive adhesive is only applied to at least a portion of a bottom surface of only the overlap portion of second end 414 such that the heat sensitive adhesive contacts at least a portion of a top surface of the overlap portion of first end 412.
In an embodiment of the invention, the labeled expanded or foam plastic container 400 can be molded from expanded polystyrene material.
In another embodiment of the invention, the labeled expanded or foam plastic container 400 is a thin walled product of high density foam plastic material.
As used herein, the term “thin walled” refers to a container that has a sidewall thickness of at least 0.5, in some cases at least 0.75 and in other cases at least 1 mm and can be up to 5, in some cases up to 4 and in other cases up to 3 mm. The sidewall thickness often depends on the container height and is adjusted accordingly to provide sufficient strength to the container. The thickness of the sidewall of the container can be any value or range between any values recited above.
The labeled containers according to the invention can be cups, used for example to store, dispense and/or drink hot, cold or other beverages, bowls to store or dispense food, such as soups, noodles, instant noodles, vegetables, meats, and oily food products, fried foods, non-limiting examples including fried chicken, french fried potatoes, fried seafood, and the like, pet foods and snacks, potato chips, pretzels, and the like, and other containers or vessels for storing and dispensing food products and other materials.
Although exemplified in
In other embodiments of the invention, the present containers have improved rim strength when compared to similarly manufactured containers without an in-mold labeled smooth circumferential label surface.
As used herein, “rim strength” is determined using a Chatillon model DFGHS digital force gauge (AMETEK US Gauge Division, CHATILLON Brand Products, Largo, Fla.). The digital force gauge is set up such that the force gauge pushes against one side of a container at a distance of one inch below the rim at a constant speed for a set distance of ¼ inch. The movement is controlled by a servo motor. When ¼ inch is reached the servo stops and the peak force value is recorded. The reported measurement is an average of determinations made on five randomly selected containers.
As a non-limiting example, the present cups can have a rim strength that is at least 50%, in some cases at least 75%, and in other cases at least 90% greater than the rim strength of a container that does not contain a label, where the base containers are made using the same equipment.
Additionally, the present containers having an in-mold labeled smooth circumferential label surface have improved rim strength when compared to similarly manufactured containers that are labeled after-molding by “wrapping a label” around the side wall of the container. As a non-limiting example, the present cups can have a rim strength that is at least 5%, in some cases at least 10%, and in other cases at least 15% greater than the rim strength of an after mold labeled container, where the base containers are made using the same equipment.
In other embodiments of the invention, the rim strength of the present containers is at least 0.3, in some cases at least 0.4 and in other cases at least 0.5 KG.
The rim of the present labeled container can be adapted to accept a lid as is readily known in the art. Further, the labeled container can be shrink wrapped, as is known in the art, to prevent, among other things, the lid from unintentionally being removed from the labeled container.
Thus, the present container can include a rim that is adapted to accept a lid and can include a lid secured to the rim. When shrink wrapping is applied to the container with lid, a secured and/or sealed storage vessel, cup, or bowl is provided.
The containers according to the invention provide improved insulation properties when compared to commercially available premium containers. In embodiments of the invention, hot liquids placed in the present container demonstrate a slower drop in temperature than commonly used premium containers. In other embodiments of the invention, cold liquids placed in the present container demonstrate a slower rise in temperature than commonly used premium containers.
As used herein, the term “premium container” refers to disposable cups and containers that have an establishment's name or other advertising or messages affixed to an outer wall surface of the container, typically used by coffeehouses, cafes, tea-houses, tea rooms, and similar eating and drinking establishments to serve drip brewed coffee, espresso- and non-espresso-based hot beverages, tea, and ice-blended drinks.
The temperature of liquids in containers over time can be measured as follows. Data is acquired using a DATAQ™ DI740 transducer-based data acquisition system using DI-5B47T-07 linearized, insulated Type “T” thermocouple modules and Omega SAI-T-120 self-adhesive Type “T” low mass, fast response 0.010″ wire (DATAQ Instruments Inc., Akron, Ohio). The thermocouple wires are placed on the containers as shown in
The test liquid is heated or cooled to a desired temperature, the data acquisition system is turned on an set to take readings at regular time intervals from wires 1010 and 1022, and the liquid is added to the container, approximately filling the volume contained therein. The temperature data from wires 1010 and 1022 is then collected over a set period of time. The hot inside percent improvement of the present container is determined by dividing the temperature difference (in ° F.) between for liquids having a temperature greater than 100° F. (38° C.) in the present container and in a prior art container by the temperature of the liquid in the prior art container and multiplying by 100%. The hot outside percent improvement of the present container is determined by dividing the temperature difference (in ° F.) between the reading by outside wire 1010 a prior art container containing liquids having a temperature greater than 100° F. (38° C.) and outside wire 1010 on the present container containing such a liquid by the temperature for the prior art container and multiplying by 100%.
In embodiments of the present invention, the hot inside percent improvement for the present containers compared to traditional paper containers (as non-limiting examples, the BISTRO™ and MISTIωUE® available from SOLO Cup Company, Highland Park, Ill.) is at least 3%, in some cases at least 4% and in other cases at least 5% 30 minutes after a liquid at a temperature of 212° F. (100° C.) is placed in the containers.
In other embodiments of the present invention, the hot inside percent improvement for the present containers compared to insulated paper containers (as non-limiting examples the INSULAIR® cups available from Insulair, Inc., Vernalis, Calif. and the PerfecTouch® cups available from Dixie Consumer Products LLC, Atlanta, Ga.) is at least 1.5%, in some cases at least 2% and in other cases at least 2.5% 30 minutes after a liquid at a temperature of 212° F. (100° C.) is placed in the containers.
The beneficial hot inside percent improvement observed with the present containers is advantageous, in that hot liquids, such as hot coffee or hot tea, remain at desirable drinking temperatures for a longer period of time than hot liquids in traditional paper containers or insulated paper containers.
In embodiments of the present invention, the hot outside percent improvement of the present container compared to traditional paper containers is at least 4%, in some instances at least 7.5%, in some cases at least 10% and in other cases at least 12.5% 60 seconds after a liquid at a temperature of 212° F. (100° C.) is placed in the containers.
In other embodiments of the present invention, the hot inside percent improvement for the present containers compared to insulated paper containers is at least 4%, in some instances at least 5%, in some cases at least 7% and in other cases at least 9% 60 seconds after a liquid at a temperature of 212° F. (100° C.) is placed in the containers.
The beneficial hot outside percent improvement observed with the present containers is advantageous, in that the outside surface of the present containers, when containing hot liquids, such as hot coffee or hot tea, remain at temperatures that are comfortable to hold the container, while traditional paper containers or insulated paper containers containing the same hot liquids are difficult to hold due to their high surface temperature, resulting in the use of sleeves and/or double cupping, which in addition to being wasteful and expensive practices, do not satisfactorily insulate the user from the high outside surface temperatures of the container.
The present containers provide both improved storage conditions for hot liquids and lower surface temperatures to the outside surface of the containers, making them easy and comfortable for a user.
Cold liquids (liquids having a temperature of less than 50° F. (10° C.), in some cases less than 40° F. (4° C.), and in other cases less than 35° F. (2° C.)) create a separate set of problems with traditionally used containers. Traditional paper containers, insulated paper containers and solid polyolefin (polyethylene, polypropylene, etc.) containers, which are often used to serve cold liquids, typically encounter problems when the ambient relative humidity is high (greater than 50% and in some cases greater than 60%), as moisture condenses on the outer surface of the container. With traditional paper containers and insulated paper containers, the moisture beads on the outer surface of the container and a portion absorbs into the paper, decreasing the rim strength of the container and a portion sits on the surface and/or runs down the side of the container to form a puddle. Moisture beading on the outer surface of polyolefin containers primarily sits on the surface or runs down the side of the container to form a puddle. In either case, the container becomes difficult and/or uncomfortable to use.
When used with cold liquids, little or no moisture condenses on the outside surface of the present containers. When a liquid at 50° F. (10° C.) is placed in the present containers and the container is exposed to conditions of 86° F. (30° C.) and 60% relative humidity (typical of a hot, humid summer day at the park) for 30 minutes, less than 2 ml of moisture condenses on the outer surface of the present container. Thus, the present containers provide unique advantages over traditional containers when used with cold liquids.
In many situations, when fat containing substances such as whole milk, cream, oil, and/or butter are placed in disposable EPS containers, or in hot liquids contained in EPS disposable containers, the fat containing substance can cause voids to form allowing the liquid to leak from the container.
In embodiments of the invention, the containers according to the invention inhibit the leakage of fat containing substances from the container.
In some embodiments of the invention, containers according to the invention do not exhibit any leakage after cream heated to 150° F. (65° C.), in some cases 155° F. (68° C.) and in other cases 160° F. (71° C.) is placed in the container and allowed to stand at ambient conditions (72° F. (22° C.) for 12, hours, in some cases 18, hours and in other cases 24 hours.
In other embodiments of the invention, containers according to the invention do not exhibit any leakage after a mixture of 12 ounces of coffee and 3 ounces of cream heated to 150° F. (65° C.), in some cases 155° F. (68° C.) and in other cases 160° F. (71° C.) is placed in the container and allowed to stand at ambient conditions (72° F. (22° C.) for 12, hours, in some cases 18, hours and in other cases 24 hours.
The present invention will further be described by reference to the following examples. The following examples are merely illustrative of the invention and are not intended to be limiting. Unless otherwise indicated, all percentages are by weight and Portland cement is used unless otherwise specified.
Polystyrene resin beads (DYLITE® 271T Beads available from NOVA Chemicals Inc., Pittsburgh, Pa.) having an average particle size of about 400 μm were pre-expanded to a bulk density of 6.25 lb/ft. 12 oz. foam cups were made using the machine described in
Rim strength of five cups from each sample was measured using a Chatillon model DFGHS digital force gauge (AMETEK US Gauge Division, CHATILLON Brand Products, Largo, Fla.). The digital force gauge is set up such that the force gauge pushes against one side of a cup at a distance of one inch below the rim at a constant speed for a set distance of ¼ inch. The movement is controlled by a servo motor. When ¼ inch is reached the servo stops and the peak force value is recorded. The results are shown below.
The data demonstrate the improved rim strength of containers made using the in-mold labeling molding machine and methods according to the present invention. The rim strength of the present containers was measured as 96% greater than that measured for an unlabeled container and the rim strength of the present containers was measured as 20% greater than that measured for an after-mold labeled or “wrap labeled” container.
In-mold labeled cups according to the invention (16 ounce using paper labels) were made as described in Example 1. The insulating properties of the present containers were demonstrated by pouring water (212° F. (100° C.)) into 16 ounce cups and monitoring the liquid and outer wall temperature using a DATAQ DI740 transducer-based data acquisition system as described above. The cups evaluated were in-mold labeled cups according to the invention using a paper label (A), standard paper coffee cups available from SOLO Cup Company (B) as is, and standard paper coffee cups available from SOLO Cup Company using a standard cardboard sleeve (C). The ambient conditions were approximately 70° F. (21° C.) and 40% relative humidity. The data are summarized in the table below.
The data demonstrate the advantage of the present in-mold labeled container when compared to traditional paper containers. The present containers maintain hot liquids at a higher temperature for a longer period of time and maintain the temperature of the outer wall of the container at a level that can be reasonably held by a typical consumer.
In-mold labeled cups according to the invention (12 ounce using paper labels) were made as described in Example 1. The insulating properties of the present containers were demonstrated by pouring water (212° F. (100° C.)) into 12 ounce cups and monitoring the liquid and outer wall temperature using a DATAQ DI740 transducer-based data acquisition system as described above. The cups evaluated were in-mold labeled cups according to the invention using a paper label (D), standard paper coffee cups available from SOLO Cup Company using a standard cardboard sleeve (E), INSULAIR cups (F), and PerfecTouch cups (G). The data are summarized in the table below.
The data demonstrate the advantage of the present in-mold labeled container when compared to insulated paper containers. The present containers maintain hot liquids at a higher temperature for a longer period of time and maintain the temperature of the outer wall of the container at a level that can be reasonably held by a typical consumer.
In-mold labeled cups according to the invention (16 ounce using paper labels) were made as described in Example 1. This example demonstrates the resistance to leaking the present containers exhibit when containing undiluted cream, as well as cream with coffee. Samples were prepared for a 24 hour leak test by placing four creams with different fat contents into eight 16-ounce in-mold labeled cups as outlined in the table below.
For each sample, one cup was prepared using 3 ounces of undiluted cream that had been steamed to 150° F. to 160° F. with a home appliance cappuccino maker. Additionally, a second cup was filled with 12 ounces of coffee (1700F), then topped with 3 ounces of steamed cream at 150° F. to 160° F. to simulate a traditional cappuccino. The table below describes how each sample was prepared. Each sample was left undisturbed then observed after 24 hours.
After 24 hours, each sample was inspected for leakage. None of the eight test sample cups exhibited any leaks. The cups were then rinsed and inspected for EPS degradation. The cups did not appear to have any dissolved EPS or voids. The data demonstrate that the present containers are suitable containers for hot coffee-type beverages, such as cappuccinos or lattes, that contain steamed cream or milk, even at high fat content levels.
In-mold labeled cups according to the invention (12 ounce using paper labels) were made as described in Example 1. The insulating properties of the present containers were demonstrated by pouring water (212° F. (100° C.) into 12 ounce cups and monitoring the liquid and outer wall temperature using an AGILENT® data acquisition/switch unit and type-K thermocouple wire as described above. The cups evaluated were in-mold labeled cups according to the invention using a paper label (T), STARBUCKS® standard paper cup with standard cardboard sleeve (U), and STARBUCKS® standard paper cup (double cupped) (V). The ambient conditions were approximately 70° F. (21° C.) and 40% relative humidity. The data are summarized in the table below.
The data demonstrate the advantage of the present in-mold labeled container when compared to traditional paper containers. The present containers maintain hot liquids at a higher temperature for a longer period of time and maintain the temperature of the outer wall of the container at a level that can be reasonably held by a typical consumer.
In-mold labeled cups according to the invention (12 ounce using paper labels) made as described in Example 1, DIXIE® paper cups (without sleeve), and TROPHY® foam cups (SOLO Cup Company), all 12 ounce cups, were evalutaed as in Example 4. The data are summarized in the table below.
The data demonstrate the advantage of the present in-mold labeled container when compared to a traditional paper container and a commercially available foam container. The present containers maintain hot liquids at a higher temperature for a longer period of time and maintain the temperature of the outer wall of the container at a level that can be reasonably held by a typical consumer.
The present invention has been described with reference to specific details of particular embodiments thereof. It is not intended that such details be regarded as limitations upon the scope of the invention except insofar as and to the extent that they are included in the accompanying claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 11/506,818 filed Aug. 18, 2006 entitled “Labeled Containers, Methods, And Devices for Making Same”, which claims the benefit of priority of U.S. Provisional Application Ser. Nos. 60/710,135 filed Aug. 22, 2005 entitled “Labeled Containers, Methods and Devices for Making Same” and 60/725,517 filed Oct. 11, 2005 entitled “Labeled Containers, Methods and Devices for Making Same,” which are all herein incorporated by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60710135 | Aug 2005 | US | |
| 60725517 | Oct 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11506818 | Aug 2006 | US |
| Child | 11838335 | Aug 2007 | US |
