Patent Grant
6887541
1. Field of the Invention
The present invention relates to an insulated packaging material which comprises a thermal insulating layer which is laminated to a face material. The face material may be film, paper or fabric. A polymer sealant material is applied to one surface of the face material. In addition, the face material can be coated with a coating material so that it is printable, thus imparting both insulating properties and print capability to the packaging material.
2. Description of Related Art
Insulated enclosures for containers are known, such as that disclosed in U.S. Pat. No. 4,871,597. This enclosure includes a first, or inner-most fabric layer, a second inner-most insulating layer which includes a polymeric foam, a third inner-most metallized polymer film reflective layer, and an outer-most fabric mesh layer. However, the use of four different layers, although providing good insulation for the container, can be cumbersome, which limits the flexibility of the container.
Also known in the film art is a thin electrical tape which comprises a polyester web-reinforced polyester film, as disclosed in 3M Utilities and Telecommunications OEM. However, this tape, which at its thickest is 0.0075 inch (0.0190 cm.), is not suitable for use as an insulated packaging material.
Thus, there exists a need to design an insulated packaging material which is inexpensive to manufacture. Such an insulator would be thick enough to provide adequate insulation, but thin enough to be flexible.
The present invention overcomes the problems associated with the prior art by providing an insulated packaging material. This insulated packaging material has enough loft, i.e., is thick enough (greater than 0.0075 inch (0.0190 cm)) so as to provide adequate insulation when used, for example, as an insulated pouch, but is thin enough so that it is flexible, for example, as juice pouches are. The insulated packaging material of the present invention is printable, thereby enhancing its use as a packaging material.
Another advantage of the insulated packaging material of the present invention is that it is less costly to manufacture than a typical roller coated or extrusion coated adhesive laminated structure, since in a preferred embodiment it includes a co-extruded film with a heat-sealable adhesive which is used to adhere the film to an insulating layer.
Moreover, in the preferred embodiment where the film and the insulating layer are both made of polyester, and include compatible adhesives, the insulated container stock of the present invention is wholly recyclable, thereby providing significant environmental advantages over known packaging materials of the prior art.
In accordance with the present invention, the insulated packaging material of the present invention comprises a thermal insulating layer having a thermal resistance of 0.05 to 0.5 CLO (0.0077 to 0.077 m2*K/W) which is laminated to a face material, wherein the insulated packaging material has a thickness in the range of 0.0075 inch (0.0190 cm) and 0.07 inch (0.1778 cm). A polymer film or sealant that is safe for contacting foodstuff is applied to the face material on the surface that will form the interior of an insulated pouch formed from the insulated packaging material.
a is a schematic cross-sectional view of another insulated packaging material according to the present invention, showing face material on both sides of a thermal insulating layer and with a sealant applied to one of the face material layers.
b is a schematic cross-sectional view of yet another insulated packaging material according to the present invention, showing face material on both sides of a thermal insulating layer and with a thicker polymer sealant layer applied to one of the face material layers to enable the insulated packaging material to support a fitment when the material is formed into a pouch.
In accordance with the present invention, there is provided an insulated packaging material. Such a material is shown generally at 5 in
The insulated packaging material of the present invention includes a thermal insulating layer shown at 30 in
The thermal insulating layer comprises an organic thermoplastic fiber based material comprising polyester, polyethylene or polypropylene. In a preferred embodiment, the thermal insulating layer is a fiberfill batt comprising polyester. A fiberfill batt sold as THERMOLITE® Active Original by E. I. du Pont de Nemours and Company is especially suitable for use with the present invention. The fiberfill batt used with the present invention has an areal weight in the range of 10 gm/m2 to 200 gm/m2, and a bulk density of less than 0.3 gm/cm3. Alternatively, the thermal insulating layer may comprise melt blown fibers, such as melt blown polyolefins, sold as THINSULATE®, by 3M.
Many other variations of insulating material for the thermal insulating layer can be used with the present invention. For instance, the thermal insulating layer may comprise a foam. The foam may be polyurethane or polypropylene, or any other foam composition as known in the art. Or the thermal insulating layer may be made of an inorganic thermoplastic fiber based material comprising glass wool, borosilicate glass or rockwool.
Alternatively, the thermal insulating layer may comprise a knit fabric, made, for example from a tetrachannel or scalloped oval fiber, sold under the trademark COOLMAX® by E. I. du Pont de Nemours and Company of Wilmington, Del. Or the thermal insulating layer may be a woven or fleece material. The insulating layer could also comprise some sort of nonwoven, such as felt, or a highloft nonwoven or needled nonwoven fabric.
The thermal insulating layer is laminated to a face material, shown at 10 in
In a preferred embodiment, hereinafter referred to as the “co-extruded film” embodiment, the face material comprises a film which is co-extruded so that it comprises two layers. Thus, face material 10 comprises a first layer 13 and a second layer 14. In this embodiment, first layer 13 and second layer 14 are made of different materials, but form one sheet of film. Second layer 14 is heat sealable—i.e., it is made of a material which has a lower melting temperature than the material of first layer 13, so that when face material 10 is heated, second layer 14 softens and adheres to the thermal insulating layer when pressure is applied. Similarly, face material 20 comprises a first layer 22 and a second layer 24. Again, first layer 22 and second layer 24 are made of different materials, but form one sheet of film. Second layer 24 is heat sealable—i.e., it is made of a material which has a lower melting temperature than the material of first layer 22, so that when face material 20 is heated, second layer 24 softens and adheres to the thermal insulating layer when pressure is applied.
Alternatively, rather than “co-extrusion”, layers 13 and 14 and 22 and 24 may be formed by coating separate layers of polymer solution onto the surfaces of the thermal insulation layer.
As shown in
Referring to
The packaging material of the present invention can further include a coating on the face material. The coating, shown at 12 in
In a preferred configuration of the co-extruded film embodiment, films with two different thicknesses are used for the face materials, such as face material 10 and face material 20 in FIG. 1. One specific example of a film which is suitable for use as face material 10 in
According to another aspect of the present invention, the face material may be modified on the surface facing away from the thermal insulating layer to facilitate printing thereon by a corona discharge treatment. Specifically, the surface of first layer 13 or 22 is modified. The corona discharge treatment may be done in addition to, or in lieu of, the coating on the face material. Or, alternatively, on top of the coating, or instead of the coating, a vapor deposited metal layer, such as an aluminum layer, may be deposited on the surface facing away from the thermal insulating layer for decorative purposes and for adding optical effects. If this vapor deposition is done, then corona discharge treatment would typically not be performed in addition to this vapor deposition.
According to another modification of the present invention, the face material may be embossed on the surface facing away from the thermal insulating layer in such patterns as may be desired for decoration. The embossing can be done on top of the coating, after corona discharge treatment, if required, and on top of the vapor deposition. Specifically, pressure and heat may be used to make certain areas of the face material thinner, so that the surface appears raised from the areas which were made thinner. Doing so in a pattern may be used to ornament the packaging material. The heat and pressure may be applied by a shaped anvil or iron in a decorative pattern. Alternatively, heat and pressure may be applied by an engraved or etched embossing roller or an engraved reciprocating die in a platen press. The heat should be applied at 200-400° F. (93-204° C.), so that the pressure applied would create permanent indentations in the packaging material. The heat should be applied as to soften at least the face material, and perhaps also the thermal insulating layer. Softening the thermal insulating layer is less critical than softening the face material, but helps the embossing process also.
In addition, the surface modification (i.e., the coating or the corona discharge treatment) may be used to facilitate bonding to another surface with an adhesive layer. In order to bond to another surface, an adhesive Layer, such as that shown at 26 in
The packaging material of the present invention may be sealed, such as with a hot knife, at its edges so that fluid cannot penetrate the edges of the label stock. Alternatively, the packaging material may be self-sealing. In this self-sealing configuration, the packaging material may be folded back onto itself, so that the top and bottom edges are already sealed. A package or pouch made from the packaging material of the present invention is preferably sealed so that fluid cannot penetrate the edges thereof.
Further in accordance with the present invention, there is provided an insulated pouch 300. Such a pouch 300 is shown generally in FIG. 3. The insulated packaging material 5 is formed into pouch 300, by sealing the peripheral edges 302, preferably by heating. Various form-fill-seal pouching machines or stand-up pouch forming machines for forming pouches suitable for holding foodstuff and liquids are known in the art, such as an Emzo® EV1 vertical liquid pouch packaging machine available from Emzo Corp., formerly of Argentina, or a Bartelt IM offered by Klockner Bartelt of Sarasota, Fla., USA, or a Toyo Model MS offered by Toyo Machine Mfg. Co. of Nagoya, Japan. Generally, under applied compression pressure and heat, such as by a heat bar in pouch making equipment, the polymer sealant material softens and adheres together to form the sealed peripheral edge.
In one region of the pouch, a frangible seal 304 portion is formed along the outer periphery. The frangible seal ruptures more easily than the other sealed regions. For example, the frangible portion 304 will break or separate when heated to the softening point or melting point of the sealant material forming the frangible portion. The portion 304 of the sealed peripheral edge of the pouch may be made frangible by heat sealing this portion at a lower temperature or pressure. Alternatively, one or more frangible seals may be incorporated within the volume of the pouch to create separate compartments (not shown) that keep apart foodstuffs within the pouch until the frangible seals rupture upon heating or upon applied pressure.
The temperature at which the frangible portion 304 separates or ruptures varies according to the material selected. In one embodiment, the frangible seal ruptures when the temperature inside the container or pouch exceeds the lower melting point sealant's melting point or softening point. For the polymers used in the facing material of the instant insulated packaging material, the frangible seals generally rupture when the temperature inside the container or pouch formed from the material exceeds 100° C. (212° F.).
A frangible target 306 or access port for accessing the pouch volume with a straw also may be provided on one side surface of the pouch 300.
A preferred pouch is formed as a stand up pouch 310 as shown in
After the pouch 310 is formed, a fitment 314 is installed into a surface of the pouch or at its periphery. As shown in
Further in accordance with the present invention, there is provided a method for making an insulated packaging material. This method is illustrated with reference to FIG. 4. In this method, a sheet of material used for the thermal insulating layer, such as fiberfill batt 30, is fed from a supply roll 45. In addition, face material 10 is fed from a supply roll 40 and is disposed such that coating 12 is oriented away from thermal insulating layer 30 and second layer 14 is facing thermal insulating layer 30. In addition, face material 20 may be fed from a supply roll 50 and is disposed such that the adhesive layer (if required, such being shown at 26 in
A sheet of the thermal insulating layer, such as 30, and at least one sheet of face material, such as 10 are fed into a heated calender roll nip between a pair of heated calender rolls 70 and 80, shown in FIG. 4. The heated calender rolls cause the surfaces of the thermal insulating layer and the face material to adhere to each other. The calender rolls are heated to a temperature which activates the heat-sealable layer but which does not melt the entire face material as discussed above. This temperature is in the range of 200° F. to 500° F. (93° C. to 260° C.), with the preferred temperature range being 280°-320° F. (137°-160° C.) for the embodiment using co-extruded 48 gauge and 120 gauge films as the face material and a fiberfill batt as the insulating layer. However, higher temperatures in the range of 450°-500° F. (232°-260° C.) can be used at high line speeds, i.e., speeds of 300 to 400 feet (91 to 122 meters) per minute. The calender rolls are displaced from one another at a distance appropriate to create a nip pressure suitable for lamination.
Alternatively, instead of using a coextruded heat sealable film, an adhesive may be applied between the face material and the thermal insulating layer to adhere them together. This adhesive would be applied by a coating roller, not shown, which would be positioned between feed rolls 40 and 50 and calender rolls 70 and 80 in
A packaging material with a thickness of greater than 0.0075 inch (0.0190 cm.) but less than 0.07 inch (0.1778 cm), preferably between 0.010 inch (0.025 cm.) and 0.040 inch (0.102 cm.), and most preferably between 0.020 inch (0.051 cm.) and 0.030 inch (0.076 cm.) is thus produced. This packaging material could be made with one sheet of face material, as in
Alternatively, instead of using a single sheet of face material, the thermal insulating layer may be fed between two sheets of face material into the heated calender roll, which causes the surfaces of the thermal insulating layer and the face material to adhere to each other. This embodiment is also illustrated in
It should be apparent to those skilled in the art that modifications may be made to the method of the present invention without departing from the spirit thereof. For instance, the present invention may alternatively include a method for making an insulated packaging material, wherein a card web comprising thermoplastic staple fibers is fed from a commercially available card machine. This card web is run in place of the fiberfill batt in the process described above with respect to
The present invention will be illustrated by the following Examples. The test method used in the Examples is described below.
For the following Examples, CLO was measured on a “Thermolabo II”, which is an instrument with a refrigerated bath, commercially available from Kato Tekko Co. L.T.D., of Kato Japan, and the bath is available from Allied Fisher Scientific of Pittsburgh, Pa. Lab conditions were 21° C. and 65% relative humidity. The sample was a one-piece sample measuring 10.5 cm×10.5 cm.
The thickness of the sample (in inches) at 6 gm/cm2 was determined using a Frazier Compressometer, commercially available from Frazier Precision Instrument Company, Inc. of Gaithersburg, Md. To measure thickness at 6 g/cm2, the following formula was used to set PSI (pounds per square inch) (kilograms per square centimeter) on the dial:
A reading of 0.8532 on the Frazier Compressometer Calibration Chart (1 in., or 2.54 cm. diameter presser foot) shows that by setting the top dial to 3.5 psi (0.2 kilograms per square centimeter), thickness at 6 g/cm2 was measured.
The Thermolabo II instrument was then calibrated. The temperature sensor box (BT box) was then set to 10° C. above room temperature. The BT box measured 3.3 inch×3.3 inch (8.4 cm×8.4 cm). A heat plate measuring 2 inch×2 inch was in the center of the box, and was surrounded by styrofoam. Room temperature water was circulated through a metal water box to maintain a constant temperature. A sample was placed on the water box, and the BT box was placed on the sample. The amount of energy (in watts) required for the BT box to maintain its temperature for one minute was recorded. The sample was tested three times, and the following calculations were performed:
Where:
D=Thickness of sample measured in inches at 6 g/cm2. (6 g/cm2 was used because the weight of the BT box is 150 gm, the area of the heat plate on the BT box was 25 cm2). Multiplying the thickness by 2.54 converted it to centimeters.
A=Area of BT Plate (25 cm)
ΔT=10° C.
The value of 0.00164 was a combined factor including the correction of 2.54 (correcting thickness from inches to centimeters) times the correction factor of 0.0006461 to convert thermal resistance in cm2×° C./Watts. To convert heat conductivity to resistance, conductivity was put in the denominator of the equation.
A label stock was made according to the process described above with respect to
The films used as the face material were of the type sold by DuPont Teijin Films of Wilmington, Del. under the trademark MELINEX® 301-H. (This film was the same film as MELINEX® 854 as described above, but it did not include the primer coating, such as 12 and 26 as shown in FIG. 1). The composition of the heat-sealable layers (e.g., 14 and 24 in
The heat sealable layers were activated at temperatures between 240 and 350° F. (116-177° C.). The data is shown in TABLE 1 below, and is graphed in
An insulated pouch was made according to the process described above with respect to
The pouches were made by combining a roll of polyester film laminated to a polyolefin with a roll of film composed of two layers of polyester film having a layer of thermal insulator between them.
The films used as the face material were of the type sold by DuPont Teijin Films of Wilmington, Del. under the trademark MELINEX® 854. The composition of the heat-sealable layers was an isophthalic acid-based copolyester and comprised 10-50% of the total film thickness; 15-30% was preferred. The MELINEX® film was laminated to a polyethylene film of the type sold by Nova Chemicals under the trademark SCLAIR® SL-1 using a solution-based adhesive of the type sold by Rohm and Haas Co. of Philadelphia, Pa. under the trademark MORTON 503A. The adhesive was applied by a 110 Quad gravure roll with a doctor blade. The films were combined in the nip roll at 190° F. (87.8° C.) and coated at a speed of 25 feet per minute, then the laminated film was dried at 160° F. (71.1° C.). The roll containing the thermal insulator was composed of 1.2 mil MELINEX® 854, THERMOLITE® Active Original, and 0.48 mil MELINEX® 854 by DuPont Teijin films and was prepared by laminating the layers in the same way described above.
A pouch was made from this insulated packaging stock using the EMZO® EV1 vertical liquid pouch packaging machine available from Emzo Corp., formerly of Argentina. Alternate pouch making equipment includes the Bartelt IM offered by Klockner Bartelt of Sarasota, Fla., USA and the Toyo Model MS offered by Toyo Machine Mfg. Co. of Nagoya, Japan.
The rollstock was fed into the pouch packaging machine and was heat sealed on four sides and cut to desired dimensions to form pillow pouches. The heat sealable layers were activated at a seal temperature of 200° C. (392° F.). Pouches were produced at a rate of 40 pouches per minute.
This application is a continuation-in-part of U.S. patent application Ser. No. 09/832,503, filed Apr. 11, 2001, now pending.
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| Number | Date | Country | |
|---|---|---|---|
| 20030129335 A1 | Jul 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09832503 | Apr 2001 | US |
| Child | 10271377 | US |
