US2475241A - Heat sealed bag - Google Patents

Description

July 5, 1949.

W. A. HERMANSON HEAT SEALED BAG Filed Feb. l, 1945 Patented July s, i949 UNITED STATES rATaNTorrlcE HEAT stalinien` BAG William A. Hermanson, Brookline, Mass.

Application February 1, 1945, Serial No. 575,715

' e claims. (ci. zoe-0.5)

The present invention relates to a heat sealed bag used particularly with infusible materials in a fluid medium such as air or water. The bag may contain a chemical such as a deodorant, an insecticide, a dehydrant or any other suitable material.

The invention in one form nds particular adaptability for deodorant and moth repellant substances such as are used in connection with clothing hanging'in closets or stored in chests or the like.

The present invention provides a bag which will wear well under heavy use and which will standV up Well during the long time that such an article is used. Some times bags of this nature are used continually as deodorants and insecticides in storage closets or rooms for long periods of time, a year or more, during which time they may be moved or rubbed inthe continual removing or changing of the stored materials. In such cases where bags of this type are used, a strong, durable bag is desirable. I have found that in such cases heat sealed bags part or separate along the sealing surface and one of the features of the present invention is to provide such a bag in which the seal remains tight and will maintain the bag in a sealed condition through its entire life.

A further feature of the present invention is that the bag may be strengthened and at the same time be more readily infusible to liquids and gases by using as one face of the bag a woven fabric heat sealed to an unwoven web with large interstices ranging from to 100 microns or more. the limiting upper limit being such that the particles of material contained in the bag will not readily drop out, and the other face of the bag may be of paper material which has been given a wet strength treatment if liquids are to be infused.

In the modiiication of the present invention, one or both sides of the bag may be made oi paper material which may be given a Wet strength treatment, and one paper sheet may be creped if desired which, with the use of a heat sealing web, will add strength to the creped sheet. b

Further advantages and purposes of the present invention will be more readily understood and appreciated from the description in the specilication below when taken in connection with the drawings illustrating the embodiment of the in- Figure 3 shows a rear view of the bag with ref erence to Figure 1.

Figures 4 and 5 show constructions in modiiied form for the walls of the bag forming the faces thereof. i f Figure 6 illustrates the arrangement of the heat sealing fibres on one face of the bag.

Figure 7 shows the arrangement of heat sealing fibres on another face ofthe bag and Figure 8 illustrates the arrangement of heat sealing libres after the faces of the bag are sealed.

In the arrangement shown in Figures 1, 2 and 3, the bag comprises two walls I and 2 which are sealed along their peripheral surfaces in the marginal areas 3, 4, 5 and 6 around the periphery of the bag. The rear wall 2 of the bag in the modiiication described in these figures comprises a loose or open woven fabric 'I to which is sealed laminated heat sealing web 8, each web preferably made of a mixture of layers of cotton and cellulose acetate ilbe'rs which have been plasticlzed to reduce the melting point range between the limits of 275 F. to 325 F. which is the same melting point range of the vinyl bres .used on the other paper sheet forming the other wall of the bag. The laminated webs may be formed in such a -rnanner that the majority of heat sealing iibres, which should be of staple, spinnable length, are aligned parallel to one another by a suitable carding process so that when the web is deposited and sealed on the woven fabric, the heat sealing fibres 9, as indicated in Figure 6, will for the majority or greater part be aligned parallel to one another across the surface of the fabric. These fibres may be parallel or perpendicular to the warp of the woven fabric or at a different angle, as indicated in Figure 6. The same type of heat sealing web may also be used on a paper web, as indicated in Figure 4 where the paper web I0, which may be porous topermit the passage of uids, is provided with a similar porous heat sealing web II having aligned cellulose acetate fibres of staple, splnnable length.

The web in Figure 4 may be used as one face of the bag providing greater or less infusibility than the other face of the bag.

The construction of the front wall forming the front face of the bag of Figures 1, 2 and 3 preferably comprises a paper web I2 to which a web of heat sealing fibres I3 has been joined. The webs I2 and I3 are joined directly after the manufacture of each web and are simply pressed together while moist. The heat sealing web I3 for this purpose is preferably made of vinyl bres or some equivalent material of non-spinnable length and preferably substantially cylindrical in shape. In such a web the vinyl fibres I4, as indicated in Figure '7, are arranged in criss-cross, intersecting or random fashion, heterogeneously dispersed or deflocculated, by means of a colloid making the solution in which the fibres are contained somewhat viscous, over the surface of the paper i2. Such fibres are, for the most part, cylindrical in form and retain such a shape when joined to the paper since no heat is used for melting the fibres in making the union of the heat sealing web with the paper. The melting points of such fibres usually range between 275 F. and 325 F.

The composite web forming the face i is preferably less permeable to liquids or fluids than the woven back face and therefore it is not as essential in the construction of this bag to maintain large, open interstices if the greater transmission of materials is to emanate from the Wall or face 2 of the bag.

In the construction of the web upon which the spinnable, staple cellulose acetate fibres, which initially may be substantially cylindrical in shape, are deposited, it will be noted that the laminated web above mentioned is joined or bonded to the woven fabric or paper web (if the latter is used) by heat and pressure so that the normal cylindrical cellulose acetate fibres 9 become flattened, as indicated in Figure 8 which shows a small sectionof a sheet under a microscope. These flattened fibres are indicated in Figure 8 as 9'. They are, however, the same fibres originally deposited on the sheet and shown as 9 in Figure 6. Figure 8 also shows the criss-cross or crossed fibres shown in Figure 7 after they have been joined by heat sealing to the fibres 9 on the sheet 1. These crossed bres I4 prime, as indicated in Figure 8, lie crossed at random over the flattened fibres 9 and afford, therefore, a greater mass of thermoplastic resin than if the heat sealing fibres -on both surfaces had been flattened by bonding to their respective webs prior to heat sealing the` peripheral edges of the bag. This union provides a stronger joint and is preferable to a joint in which suflicient heat is applied to cause the fibres to lose their identity by flowing together or in which the fibres are joined in their original cylindrical form without first bonding the carded sheet to the web or woven fabric.

If a pleated, multiple folded or creped sheet is used for one face of the bag, such as illustrated by l5 in Figure 5, the entire face may be provided with laminated Webs of mixtures of cotton and cellulose fibres, such as illustrated in Figure 6, or with a vinyl bre web such as shown in Figure 7. It is preferable where the crepe provides great permeability, becauseof its increased surface area, to use the heat sealing web of cotton and cellulose acetate fibres such as are'dep'osited on the woven fabric 1 and to provide the other face of the bag, which may be of paper, with a vinyl bre web of short staple length such as' shown in Figure 7.

The bag may be filled in any suitable manner, the filling of the same forming no part of the present invention.

The heat sealing webs are applied over the entire inner faces of the front and back sheets forming the walls of the bag. These sheets are preferably thin and flexible although they may be of stiff or semi-stiff material, if desired. The

bag itself may be hung up or laid down and for the purpose of hanging it up, a hole I 8 maybe provided in one peripheral sealed margin.

Within the specication set forth above, the invention may take various forms and shapes without changing the substance of the same.

Having now described my invention, I claim:

1. A 'bag adapted to be infused with Water and other liquids comprising two flexible, thin sheets in face-to-face contact around their peripheral surfaces and permeable to a fluid medium, one sheet having a carded heat sealing web bonded by heat thereto, said web having heat sealing fibres of spinnable, staple length, the other sheet having a web of deflocculated heat sealing fibres shorter than spinnable length pressed thereto without heat, the peripheral surfaces of the sheets being bonded together by heat.

2. A bag adapted to be infused with water and other liquids comprising two flexible, thin sheets in face-to-face contact around their peripheral surfaces and permeable to a fluid medium, one sheet having in intimate contact therewith a carded heat sealing web of plasticized cellulose acetate bres of spinnable, staple length by heat bonding, the other sheet having a web of deflocculated heat sealing vinyl fibres shorter than spinnable length pressed thereto without heat, the two heat sealing webs having approximately the same melting point range and the sheets being bonded together by heat about their marginal surfaces.

3. A bag adapted to be infused with water and other liquids comprising two flexible, thin sheets in face-to-face contact around their marginal surfaces, one sheet comprising an open woven fabric having a carded heat sealing web of plasticized cellulose acetate fibres of spinnable, staple length, said web being bonded by heat to the woven fabric, the other sheet having a web of deflocculated heat sealing vinyl fibres shorter than spinnable length pressed thereto without heat, the two heat sealing webs having approximately the same melting point range and the sheets being bonded together about their marginal surfaces by heat.

4. A bag adapted to be infused with water and other liquids comprising two flexible, thin sheets in face-to-face contact around their peripheral surfaces and permeable to a fluid medium, one sheet having a carded heat sealing web bonded by heat thereto, said web having heat sealing fibres of spinnable, staple length, the other sheet having a web of deflocculated heat sealing fibres shorter than spinnable length pressed thereto without heat, the peripheral surfaces of the sheets being bonded together by heat, the heat bondings being sufficient to flatten partially the fibres Without causing them to lose their identity.

5. A bag adapted to be infused with water and other liquids comprising two flexible, thin sheets in face-to-face contact around their peripheral surfaces and permeable to a fluid medium, one sheet having a carded heat sealing web bonded by heat thereto, said web having heat sealing flbresof spinnable, staple length, the other sheet having a web of deflocculated heat sealing fibres shorter than spinnable length pressed thereto without heat, the peripheral surfaces of the sheets being bonded together by heat, at least REFERENCES CITED The following referenices are of record in the le of this patent:

Number UNITED STATES PATENTS Name Date McKee Aug. 9, 1932 Kllander et al. Aug. 16, 1932 Saltlsbers Dec. 6, 1938 Reed May 28, 1940 Hirschhorn Aug. 4, 1942 Menzel Dec. 29, 1942 Heaton Oct. 12, 1943 Weisman May 29, 1945 Osborne Jan. 28, 1947

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