Patent Application
20100247823
This disclosure relates to a molten material and package combination, and a method for packaging hot melt material.
A pouch or bag having a polyethylene inner heat seal layer, and having an aluminum foil layer have been typically used in packaging for hot melt or molten material, such as hot melt polyurethane (having, e.g., a temperature of about 250° F.). Such hot melt material is typically poured into a vertically supported pouch (laminated foil and heat seal film). In a conventional method, the air in the pouch is typically purged out of the pouch with dry nitrogen gas to eliminate moisture. The dry nitrogen gas also expands the pouch. The pouch is then sealed, and allowed to cool to the solid phase with the pouch in the vertical position. It is believed that the “vertical” cooling step is utilized to yield a uniform shape and prevent pouch material from folding and becoming embedded within the molten mass. Such vertical cooling of a 2 pound package of hot melt polyurethane from about 250° F. to ambient temperature of about 68° F. typically takes about 8 hours. Significant degradation of molten material due to cross-linking of reactive polymer can increase with long cooling times exceeding more than about 3 hours.
Disclosed herein is a method for packaging molten material that eliminates the need for purging of air with an inert gas. The disclosed method can be used in place of conventional approaches.
In one aspect, the method comprises filling a retort pouch or bag, folding the top of the pouch over near or at the molten material line to expel air from the pouch, and then sealing the pouch.
In another aspect, the method comprises laying a side of the filled and sealed pouch on a metal sheet, the side being substantially transverse to the bottom of the pouch.
In another aspect, a molten material and package combination is formed by filling a retort pouch from the top of the pouch with molten material, the pouch having a bottom opposite the top of the pouch, folding the top of the pouch over near a molten material line in the pouch to expel air from the pouch, and sealing the pouch.
Non-limiting embodiments will now be described with reference to the accompanying drawings.
It will be appreciated by those skilled in the art, given the benefit of the following description of certain exemplary embodiments of the method and packaging disclosed here, that at least certain embodiments of the invention have improved or alternative production aspects. These and other aspects, features and advantages of the invention or of certain embodiments of the invention will be further understood by those skilled in the art from the following description of exemplary embodiments.
The method disclosed herein can reduce or eliminate drawbacks of conventional approaches. The method disclosed herein can provide for more efficient packaging of molten material. The method disclosed herein eliminates the need to purge air from the packaging with an inert gas, and thus eliminates the need for and operation of purging equipment. The method can be useful for packaging any molten material, e.g., molten material having a melting point between about 150 to 300 degrees Fahrenheit. The method can be to package molten material in a suitably sized package, e.g., about a 2 to 50 pound package of molten material. In a preferred embodiment, the molten material is packaged in a 2 to 10 pound package of molten material. A more preferred embodiment can be 2 to 5 pound package of molten material, or about 2 pounds of molten material.
In accordance with an example of the disclosed method, a retort pouch or bag having an inner heat seal layer and a foil layer can be used. The inner heat seal layer can comprise any suitable material, including e.g. polypropylene and polyethylene. In a preferred embodiment, the inner heat seal can comprise a high melting polypropylene. The foil layer can comprise an aluminum foil. As shown in
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It has been found that in following the above steps there is not enough moisture present in the minimal airspace of the pouch to form undesirable moisture induced skin on the material. The flat shape allows multiple pouches to be placed inside different cartons to create many package configurations. This method eliminates the step of purging air with an inert gas, as well as time-consuming steps, after cooling, of clipping a corner of the pouch, evacuating the inert gas, and resealing the pouch.
Following the method disclosed herein results in a packaged molten material that does not have significant wrinkling and in which no portion of the packaging is significantly embedded in the packaged material. After the packaged material is cooled to the solid phase, such as cooling at ambient temperature, the packaged material can be easily transported to a point of use. At the point of use, the packaging can be removed from the packaged material, and the packaged material can be heated in a suitable apparatus to a molten state and applied in accordance with its intended use. Such intended use can be an adhesive, e.g., a hot melt adhesive, to bond similar or disparate structures and/or materials together. The packaging can be readily removed from the packaged material since, as noted above, it does not become significantly embedded in the packaged material.
The methods disclosed above in connection with the present invention are hereby incorporated herein with respect to another aspect of the present invention, i.e., a molten material and package combination 60, shown in
Those of skill in the art will recognize that any or all the steps described above can be performed with apparatus and/or devices that are automated, and which can be facilitated with computer control, and are thus included within the scope of the present invention.
It will be apparent to persons skilled in the art that various modifications and alterations to the preferred embodiments mentioned above may be made without departing from the underlying concept of the inventions. All such modifications and alterations are included within the scope of the present invention.
