Manufacturing container or tube from paper; or other manufacturi – Container making – Pliable container
Reexamination Certificate
1999-02-25
2001-11-20
Kim, Eugene (Department: 3721)
Manufacturing container or tube from paper; or other manufacturi
Container making
Pliable container
C493S190000, C493S936000
Reexamination Certificate
active
06319184
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to plastic bag and film products that may be used for a multitude of purposes such as, but not limited to, fast foods, supermarkets, retail merchandise and point-of-purchase bags. More specifically, this invention relates to placing a useful cold seal in these plastic bags and products. For example, the cold seal is used so the bags may be fabricated in the lay flat disposition but thereafter take on specific shapes and forms, such as a square bottom. This disclosure covers the methods by which the cold seals are placed in such products.
BACKGROUND OF THE INVENTION
Cold Seals Generally
Cold seals are known. Cold seals are also infamous in plastic bag manufacture. Some explanation is in order.
When plastic was first considered as a bag material, difficulty was encountered in sealing such bags. The desired seal was the so-called “hot seal.” In such a hot seal, two layers of plastic were sealed together under a temperature and pressure where the molecular structure of the two bag layers permanently bonded and fused together.
A permanent “hot seal” is easy to identify. If one tries to tear apart the joined layers of a hot seal on a plastic bag, the seal—being two layers thick—will not part. Instead, either of the two joined layers will separate well before the hot seal itself will separate.
Unfortunately, where insufficient dwell time, insufficient pressure or insufficient temperature is utilized in what is attempted to be a “hot seal”, an imperfect hot seal results which is commonly referred to as a cold seal. Such a “cold seal” can be recognized by tearing the cold seal a part. When a cold seal is torn apart, the two joined layers of plastic separate with their structural integrity intact. It is the “cold seal” that fails and tears.
The infamy of “cold seals” relates to the customer public relations disaster, which almost always occurs when a defective “hot seal” opens in the manner of a “cold seal.” Simply stated, the customer is usually leaving the store with his plastic bags filled with carefully selected and purchased merchandise. During this departure, the defective “hot seal”—which in reality is a “cold seal”—opens. The merchandise crashes to the floor—usually with some damage.
For the reasons set forth above, the prior art has been stead fast in its avoidance of “cold seals.”
Cold seals have found one place where they have utility. Cold sealing of plastic film is a well-known process and has been applied in a multitude of ways in bag stacks to cause the bag plies to stick together in the bag pack and self open the next bag in sequence. This is described in U.S. Pat. No. 5,183,158 to Boyd and U.S. Pat. No. 5,562,580 to Beasley, et al. Both Boyd and Beasley reveal bags that have been corona treated in order to selectively cold seal—or weld—the plastic film layers together in a stack of bags.
It is to be understood that in this use, the “cold seal” does not form a structural element of the bag. In fact it has been the very careful intent of the prior art to avoid cold seals in any structural element of a bag. As will be seen herein, I claim invention in utilizing “cold seals” for the essential “one time opening” of bags fabricated in the lay flat condition to open and square out with a square bottom.
Plastic Bags Generally
Common plastic bag styles used by retailers in fast food chains, supermarkets, and general merchandise, as well as in point-of-purchase applications, are typically of the bottom seal or sideweld variety and have hot seals at these locations.
These bags are usually gusseted along their sides or along the bottom with the open bag mouth at the top. Many of these common bags have carrying handles, usually of the strap variety or die-cut holes. Typical plastic bags used in supermarket applications are about 0.0005 to 0.00065 in gauge; those used in retail merchandise bags are from 0.0005 to 0.0001; fast food bags are usually from 0.0007 to 0.00125, and; those used in point of purchase applications are typically from 0.001 to 0.004 mil thick.
Retailers usually desire to have a bag stand up on its own during clerk bag loading. Usually square bottom paper bags are used instead of plastic bags. Simply stated, square bottom paper bags stand up; plastic bags used in point-of purchase applications typically do not stand up well at all, unless they are a pouch which typically takes on a rounded shape instead of a rectangular shape like boxes.
Common plastic bags have a cost efficiency. Unfortunately, for clerk and customer, such bags have a “use” inefficiency. This “use inefficiency” relates to the multiple steps, which must be undertaken to use such bags.
Common plastic bags when manually put into use usually follow a certain sequence.
First, the clerk's fingers open the bag mouth.
Second, the clerk at one hand grasps one side of the open mouth at the top.
Third, the clerk with the other hand grasps the opposing side of the bag mouth at the top.
Fourth, the bag is pulled upward to capture air and billow open.
Fifth, the clerk's hand is inserted in the bag to “find the bottom” as the bag is placed on the packing surface.
Sixth, once the bottom is found, the hand is withdrawn, and; seventh, the user grasps the merchandise and begins loading the bag.
Variations on this theme may include the shaking of bags to get them open, the support of such bags in the open position from special racks or any of a myriad of other techniques necessary to simultaneously fill and support the bags.
Most common plastic bags are not fabricated with joints and structure to allow the bag to stand up. It would take a user several seconds to open up and put a common plastic bag in the right shape to make it stand up. It is impractical for a user in a high volume retail outlet to do this, as the cost of labor is substantial. This is one key reason most fast food restaurants still use paper bags.
Contrasted with this technique, paper bags when opened are usually set upright and allow the user to place merchandise inside the bag at the bottom. Likewise, when the bags are unloaded at home, again they are capable of standing upright. It is for this store loading convenience, the upright standing paper bags are preferred by clerks and for the home unloading convenience the upright standing paper bags are preferred by customers.
The need for economical square bottom, thin-gauged plastic bags that stand up is well-known. Some 30 plus patents in the field reflect the extreme need, but yet not a single process exists that is cost effective. The cumbersome processes associated with the many alternate methods of creating square bottom, stand-up plastic bags is evident in the bottom seal bag variety of Hansen et al, U.S. Pat. No. 3,988,870 and 4,929,224; Brinkmeier U.S. Pat. No. 3,896,709; La Fleur U.S. Pat. No. 3,915,077 and Platz, U.S. Pat. No. 3,917,159. Others have come closer to an economically viable product with the means illustrated in Ross, U.S. Pat. No. 5,102,384, and Roen U.S. Pat. No. 4,717,262. But as of yet, no process has been anywhere close to the cost effectiveness of current T-shirt manufacturing processes or that of common bottom seal and sideweld plastic bags, all these bags without a “squared out bottom.”
In the high-speed bag manufacturing processes used throughout the world, plastic bags are typically made from tube stock. This tube stock is cut out and sealed—either bottom sealed or side welded—as the last step before being packed in a carton.
Placing a square bottom on an already manufactured bag has proven to be costly. To clamp and fold over and/or seal gussets together after a bag has already been cut and sealed from its tube stock in order to create a square bottom bag is not economically viable. As illustrated in the above patents, Ross '384 and Platz '159, this bag forming process requires a costly secondary operation after the bottom sealing process is completed and the bag has been cut free from the tube stock. These processes use a relatively sophisticated grasping and clamping to accomplish the folding proce
DeMatteis Robert B.
Pansier Donald
Bob Dematteis Co.
Kim Eugene
Townsend and Townsend / and Crew LLP
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