Method for producing a thermoplastics folder and the like by...

Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor

Reexamination Certificate

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Details

C156S251000, C156S267000, C156S290000, C156S308400, C229S067100

Reexamination Certificate

active

06254707

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a method and article produced thereby from laminated thermoplastic material having a uniform and an attractive marginal edge adjacent to seal by simultaneous sealing and tears/cutting of the marginal edge of the material thereby producing an attractive and finely finished article.
HISTORY AND BACKGROUND OF THE INVENTION
Stationery articles such as folders, portfolios and pocket document binders have long been produced such as illustrated in U.S. Pat. Nos. 5,876,143; 5,059,052; 5,752,721 and 5,417,509, including paper folders such as U.S. Pat. Nos. 4,934,584 and 3,516,599. Vinyl folios and folders are illustrated in U.S. Pat. Nos. 5,873,513 and 4,629,349. More specifically, polyethylene, polypropylene and polyvinyl chloride articles are illustrated in patents U.S. Pat. Nos. 5,275,438; 5,445,417 and 5,266,140.
Today, paper materials are less likely to be used in stationery paper products having pockets because of the durability factor. They do not stand up under heavy service necessating more durable materials. Problems have developed with the use of folders made of certain thermoplastic materials which tend to pick up the ink from inserted letters or the like leaving the transferred ink on the folders in an unsightly manner, and often where the folders are transparent, causing interference with subsequent articles placed in the folders because of ink transferred thereon at an earlier date.
Polypropylene has been found to be a thermoplastic material which when made into folders does not pick up ink from the papers inserted therein; whereas polyethylene and polyvinyl chloride tend to pick up ink.
Metallic polyethylene, polypropylene and polyvinyl chloride thermoplastic films are found to produce exceptional fine finished articles when used with this process probably due to the heat transfer of the metallic particles in the thermoplastic films. These metallic thermoplastics consist of aluminum powders, giving a special sheen to the folder as for example in silver, gold, red, green, blue, purple, etc. The metallic thermoplastics are available from American Profil of Cedar, Rapids, Iowa.
Where heat sealing is used in the manufacture of stationery articles such as folders and the like, it has been found necessary to use a two-stage system for producing the folders. This two-stage involves sealing the marginal edges followed by a cutting operation to remove the waste of flash materials adjacent the sealed edge. Unfortunately, it has been found that the cutting operation, being subsequent, often leaves marginal strips adjacent to seal which are uneven and unsightly. Further, the subsequent cutting and squaring off of the edges produces sharp corners which often injured or at least cause annoyance to the individual using such articles. In particular, polypropylene is ordinarily difficult to tear.
In most instances where a heat sealed is used, the attempt is to make the seal even in length, height and width. Depending on material, it has been found that if the seal is made having serrations, there is less likelihood of leakage or opening up of the seal. To some extent this is dependent upon the type of thermoplastic material used.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of this invention to provide a method and the article produced thereby which results from the simultaneous sealing and tear/cutting of the marginal edge of the article.
Another object of this invention is to provide a method and article produced thereby which uses ultrasound to vibrate the die having both the cutting and sealing edges to simultaneously seal and tear/cut the margin of the article produced.
A further object of this invention is to provide a method and the article produced thereby which utilizes polypropylene film such as sheet or role material.
Still further object of this invention is to provide a method and the article produced thereby which provides an even bead along the marginal edge of the article produced.
And a further object of this invention is to provide a method and the article produced thereby which has a uniform serrated seal and a marginal edge parallel to the serrated seal.
A still further object of this invention is to provide a method and the article produced thereby in which the corners of the article are rounded rather than pointed.
A further object of this invention is to provide a method and the article produced thereby which eliminates prior two step operation of sealing and subsequent cutting thereby reducing cost of operation.
Another object of this invention is to provide a method and the article produced thereby which gives the article a finished look by producing a uniform bead along the marginal edge.
Yet object of this invention is to provide a method and the article produced thereby which provides a die bar which by special machining eliminates distortion of the die bar providing a distortion factor of not over 0.001″.
A still further object of this invention is to provide a method and the article produced thereby which utilizes a step arrangement in the seal edge of the die to allow for even flow of the plastic material depending upon of the number of laminating sheets to be sealed by the seal operation.
A further object of this invention is to provide a method and the article produced thereby which relieves the stresses produced during the seal and tear/cut operation by relieving overflow material produced thereby producing a finer finished article.
Another object of this invention is to provide a method and the article produced thereby which enables the manufacture to tear or strip the article from the excess waste material around the margin which was earlier not possible due to the difficulty to tear polypropylene material.
Yet another object of this invention is to provide a method and the article produced thereby which utilizes ultrasound in order to seal and tear/cut the material in a manner to provide uniform edges to the article.
In summary, this invention relates to the method and article produced thereby which provides an attractive uniform marginal edge with a strong leak proof seal.
These and other objects will be apparent from the following description and the drawings which are described as follows:


REFERENCES:
patent: 3516599 (1970-06-01), Buttery
patent: 4629349 (1986-12-01), Pitts
patent: 4934584 (1990-06-01), Wyant
patent: 5059052 (1991-10-01), Casper
patent: 5266140 (1993-11-01), Kohno
patent: 5275438 (1994-01-01), Struhl
patent: 5417509 (1995-05-01), Schwartz
patent: 5445417 (1995-08-01), Bromer et al.
patent: 5752721 (1998-05-01), Balbas
patent: 5863383 (1999-01-01), Bussey
patent: 5873513 (1999-02-01), Ong
patent: 5876143 (1999-03-01), Ong

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