US2158755A - Laminated sheet material for use in making paper bags or wrappers - Google Patents

Description

7!!!!I/lflllfllllrllllll 3 Sheets-Sheet 1 FIIIIIIl/flllfllrltrlflll r/lrlIll/Ilf/ll/llllfllfl! T. A. HODGDON ET AL LAMINATED SHEET MATERIAL FOR USE IN MAKING PAPER BAGS OR WRAPPERS Filed Sept. 16, 1936 I May 16, 1939.

I N V E! YTOR 5, new ,1 110472011, BY f lfladydolz,

ATTORNEY.

May 16; 1939.

T. A. HODGDON El AL LAMINATED SHEET MATERIAL FOR USE IN MAKING PAPER BAGS OR WRAPPERS Fil'ed Sept 16, 1956 5 Sheets-Sheet 2 INVENTORi Zeadam JZ 170470 0 flzalfiffimfqdazz,

ATTORNEY May 16,1939. T. A. HODGDON ET AL LAMINATED SHEET MATERIAL FOR USE IN MAKING PAPER BAGS 0R WRAPPERS 3 Sheets-Sheet 3 INVENTORS ATTORNEY.

Patented May 16, 1939 LAMINATED SHEET MATERIAL FOR USE IN MAKING PAPER. BAGS OR WRAPPER/S Theodore A. Hodgdon, Wilbraham, Mass., and

, Paul E. Hodgdon, Readsboro, Vt.

Application September 16, 1936, Serial No. 101,098

3 Claims.

This invention broadly comprises means for laminating a plurality of webs of sheet material of what is known as hydrated sulphite pulp, or in the trade, as glassine paper which possesses a high degree of hydration and having highly calendered surfaces, so that it is practically grease-proof. It may also be made moistureproof when coated, or treated, with moisture-' proof materials,

One of the objects of the invention is to coat the base, or transparent glassine sheet of the bag-forming material with a suitable wax, that serves the double purpose of rendering the paper transparent, and, as an adhesive for binding the 1 layers or webs of the paper together.

' At the present time, bag manufacturers wishing to produce a bag with a transparent window in its fr nt, back, or sides, must usually perform a combining operation of the transparent strips with the opaque strips, before the completed bagforming material may be put through a bagforming machine; The present invention is designed to remove this objection and to produce a laminated sheet having the requisite number 5 of layers and having a transparent window, or a series of windows, wherever desired in the finished bag, and, ready for a bag-forming machine; thus lessening the cost of manufacture of the bags.

. A further object is to provide a sheet of laminated bag-forming and wrapping material that is formed with perforations, or openings, in a side or sides, of the outer covering of the lamination on its outer surface, of the finished bag, so that the contents may be readily observed through the transparent base sheet of the bag.

A further object is to provide a bag-forming, or wrapper sheet, in which its entire inner surface, or base piece, is composed of transparent glassine material, and substantially grease-proof, and nonabsorbent of wax, whereby the contents of the bag may be protected throughout its entire inner surface.

This invention is particularly designed for making laminated sheet material from glassine, which is a paper made from thoroughly hydrated sulphite pulp, and having highly calendered surfaces, so that it is substantially grease-proof and non-absorbent of wax. It is designed to produce a bag having a transparent base member that is laminated with strips, or, with a full-width opaque perforated member.

An object of the present invention is to supply,

for. wrapping and bag-making purposes, a

laminated sheet material which will be an im- 55 provement from a standpoint of flexibility. that is;

more able to withstand bendin folding and creasing, as on a bag or wrapping machine, without easily separating, opening or coming apart at the creases, or folds. This is accomplished by applying a coating of wax, which, when cooled, will remain in a thin, plastic film on both of the opposing surfaces which are to be pressed face to face, thus adding to the flexibility of each sheet, even before lamination, thus adding to the total or final flexibility of the laminated sheet.

Means is provided for cooling the laminated sheet, as it leaves the pressure rolls and a second roll is provided, spaced some distance from the cooling roll of smaller diameter. The laminated web, from this second roll, now passes around two cooling rolls I1 and I8, preferably of a temperature of about F. A take-up, or winding roll, for the completed sheet, is employed, and a suitable tension roller interposed between the takeup roll and the cooling rolls.

Further objects and nature of the invention will appear in the body of the specification with reference to the drawings and the appended claims.

Referring to the drawings:

Fig. 1 shows means for applying the transparent coating material to the base or transparent sheet on one surface only, and on the under surface of the three opaque strips which receive their coatings of wax from the same coating supply which is in the receptacle through which the base sheet passes, or is drawn, and which material is'carried up to the nip, by the rotating of the lower pressure roller.

Fig. 2 is a section of the finished laminated sheet, before the same is slitted to form the individual wrapping, or bag-forming material, shown in Figs. 3 and 4.

Fig. 5 is a detail view of a detached portion of the laminated bag-forming material, or wrapping material, before it is folded to form a bag or wrapper.

Fig. 6 is a detail view, showing diagrammatically a machine for coating both surfaces of the opaque and transparent base sheets of glassine material. Fig. 7 is a perspective view, showing one of the folded bags with the full length transparent window of the base material extending the full length of the frontof a finished bag.

Fig. 8 is a cross sectional view on the line 8-8 of Fig. '7, showing the lining of the transparent base material extending over the entire inner surface of a bag. t

Fig. 9 is a longitudinal sectional view on theline 9--9 of Fig. 8, illustrating the folded ends of a bag and the inner member of transparent material.

Fig. 10 is a modification of a completed bag, illustrating a window or perforation in the opaque material disclosing the inner transparent base member.

Fig. 11 is a view similar to Fig. 10, showing different shaped perforations in the opaque material of the bag as trade-marks as well as window openings in the opaque material.

Fig. 12 is a modification in which the outer or opaque layer is coated on one side only with a wax of low melting point for flexibility and adhesive qualities, while the other sheet or base transparent sheet is coated all over on its surface with high melting point wax, and for only a portion of its other surface with high melting point wax, so that those portions of the transparent base sheet which are covered by the opaque strips, will be left free of the high melting point wax, and the central portion of the transparent base sheet, which in the finished sheet forms the transparent window, will be coated on both sides for greater transparency and higher polish as produced by the high melting point wax.

Fig. 13 is a view on the line |3-l3 of Fig. 12, showing the mask means for preventing the wax from being applied to the opposite edges of the transparent base web of paper, and on which edges the opaque webs are secured having the low temperature melting point wax, or other adhesive thereon.

Fig. 14 is a cross sectional view on the line l4-l4 of Fig. 12, of the finished web, shown in Fig. 12, illustrating the high temperature melting point wax for imparting a polish and the low temperature melting point wax for adhesive qualities and for flexibility.

Fig. 15 is a further modification, showing the rotary perforating die means for forming openings in the single, outer opaque web covering of full width, by means of a pair of rotating dies.

Fig. 16 is a view of another form of finished bag material having windows, and showing in dotted lines where the laminated bag material is separated by the bag-folding machine, to form the individual bag, or wrapping sections.

Referring to the drawings in detail:

I indicates a supply roll of the transparent glassine material which passes over the tension, or adjusting guide roll 2. The roll I is supplied with a suitable brake device, (not shown), for adjusting the rate of travel of the unwinding of the web. 3 is a supply tank containing the suitable coating waxes, in which the pressure roll 4 is partially submerged. The web, from the roll I, is drawn tightly around the bottom surface of the roll 4, to prevent the admission of the wax, between the web and the roll, and thus keep the inner surface of the web dry. The wax, in the receptacle 3, may be heated, according to the requirements of the material to be laminated. It, therefore, receives a coating on its under surface, or, as indicated at 5. 6, 6 and 6" designate three independent rolls of opaque glassine paper from which the three opaque strips I, 8, and 3 are drawn over the tension roll I II. The rolls 5, 5 and 5" each have an independent brake device. These strips engage, or come into direct contact with the wax, 3, on the under surface 5, of the transparent, full width base sheet 'I of transparent glassine material, throughout their full widths of their under sides, which excludes the air and aids in the adhesion at the nip of the rolls. They pass under the upper pressure I l which, with the roll 4, operates to cause the webs to adhere and form the laminated web l2, leaving the transparent portions l3 and M. The material 3 serves the double purpose of protective properties and as an adhesive. The web l2 passes over the adjustable and cooling, or drying roll l5 having a temperature about 70 F.; then, over the second adjusting roll I6; then over and under the cooling, or drying coils I1 and I8 having a temperature of 180-190 F., the tensioning roll I9 and the takeup roll 20. The strips 1, 8, and 9 serve to provide the opaque strips, or portions, of the finished bag and wrapping material.

The wax, is, in every case, substantially moisture-proof, as well as polished in appearance when dry or cool; thus, it serves a triple purpose; (ll) adheres the opaque strips to the base sheet; (b) imparts protective qualities to the base sheet; and (0) increases the transparency and polished appearance of the transparent strips of the base sheet; that is; the portions of the transparent base sheet which are not covered by the opaque strips. The temperatures used in the rolls l5, l1 and I8 have been referred to above.

It will be seen, from Fig. 1, that the center opaque strip 8 is approximately twice the width of the opaque strips 1 and 9, but not exactly, and this strip is later slitted along the medium line 2| to form the two bag-wrapping finished members, shown in Figs. 3 and 4, in which the middle web 8 defines the two marginal opaque strips 22 and 23 and the visible transparent portions of I3 and I4.

Referring to Fig. 5, the finished laminated web I2 is shown with the severed edges 24 and 25,

which represent the length of one of the finished bag elements, before it is finally folded by the bag-making machine. This view shows the partial folds, or crimps, of the bag at 26 and 21; the finished bag being indicated in Figs. 7, 8, and 9, in which the full width transparent, base material l of glassine extends completely around on the entire inner surface of the bag, which is an important feature of our invention, to protect the contents and to increase the thickness of the bag.

Actually, the transparent base material is, at this point, not only grease-proof glassine, but has been rendered moisture-proof, as well, in the operation shown in Fig. 1. Thus, we might say in which the full width transparent base sheet I of coated glassine extends completely around on the entire inner surface of the bag, which is an important feature of our invention, inasmuch as the base sheet is of a highly grease-proof glassine to start with, and is coated with moisture-proof material in addition, to protect the contents.

It will be seen from the description of the apparatus, shown in Fig. 1, that the takeup roll 20 is a finished laminated web, ready for the bag-forming machine, and does not require any further building up of the strips for forming the bag material, before it is folded on a bag-forum ing machine.

Referring to Fig. 6, in which the supply roll 28 of the transparent base glassine sheet passes over the tension roll 29 and under the lower pressure roll 30, which is partially immersed in a tank of coating wax 3|, the web 32, then passes under the submerged roll 33. This web is therefore coated on both sides, as it leaves the roll 33. A second web 34, from a second supply roll 01' opaque glassine material, passes under the sub merged roll 35, which i:-'. in the same paraffin coating wax, located in the tank 3!, where it is Yll also coated on both ofiits sides, as shown, for laminating and for transparency. The two webs then come together and are forced into close contact by means of the pressure rolls 30 and 36, to form the finished web 31. This web is therefore coated on both of its upper andlower surfaces, with the coating wax, as well as on the two inner surfaces for increasing its transparency. I

Therefore, it is to be understood that the view shown in Fig. 6 coats both sides of the base sheet, as well as the two opaque side strips, corresponding to strips 1, 8, and 9 in Fig. 1.

Thus, a bag may be formed having a transparent window the full length of its face or sides, fully coated with moisture-proofing material all the way around on both its inner and its outer surfaces.

Referring to Fig. 12, which illustrates means for coating the transparent base sheet over the entire width of one of its sides or surfaces with a wax, having a high degree melting point, then I coating only a strip of its opposite surface with the same high degree melting point wax, leaving side portions of the base sheet uncoated, said side portions to later receive a coating of low degree melting point wax or other knownadhesive, at the time they are covered by the opaque strips. I

In this apparatus, there are two supply rolls 42 of opaque glassine paper which pass under the waxing roll 43, which is partially immersed in the supply tank 44 of low degree melting point wax, and coats one side only of the opaque web strips 42' from the rolls 42, as shown in Fig. 12. The webs then pass over a doctor element 45 to remove any surplus and under the lower pressure roll 46, of the drip tank 41. At this point they are drawn upward to the other upper pressure roll 48, where they meet the web 49 of transparent glassine material from the supply roll 50.. The glassine, fromthis web, engages the waxing roll which rotates-in a bath of high melting point coating wax 52,,and is coated on its entire lower side only; then, around the conditioning roll 53 that is steam-heated; then over the waxing roll 54, which is located in the supply tank 55, of wax of high melting point, as I in tank 52'. In this construction, it is desirable that only the upper center portion 56 (see Fig. 13), be left with the transparent coating wax 52 of high melting point to give it a polished surface. 51 and 58 are mask elements located on the rod 59 and adjustable to prevent the under surface of the web 49 from taking up any of the high melting point coating wax 52 at the opposite under side edges of the web 49, from the roll 54, whereby portions of the opposite side edges of the web 49 are left dry for receiving the webs of-opaque materiaLfrom the two rolls 42 and is forced into contacttherewith by the rollers and 48. This operation produces the laminated bag material for forming the bag shown in Fig. 7; that is to say; with the central portion that is transparent and extends the full length of the bag. The finished laminated web 60 is then passed around the cooling and tension rolls 6| and 82 and over and under the cooling and drying rolls 63 and 54, which have therein a cooling, or drying temperature medium, depending upon the coating material used, as described, to the final takeup 65.

Referring to Fig. 15, which is the same as Fig. 12, with the exceptions that the opaque web is full width from the supply roll 42" that passes or article, shown in Fig. 10.

It is particularly understood that the finished bag material that is formed, as described, is of a grease and moisture-proof nature, as well as transparent. The transparent portions are for inspection of the contents. The opaque portions give a clean, white appearance to the package 7 as well as a double thickness.

Thelaminated sheet material, having a transparent base material and opaque strips, is a complete and finished article, ready for the bag manufacturer, and, whether with the continuous window, or the openings of various forms in the opaque material, as shown in Fig. 11, are used. This article is, therefore, of double thickness.

It should be particularly understood that we do not limit ourselves to the size, number, or location of the transparent window portions of the bag or wrapper, as they can be extended to cover the entire surface or face of the package, as well as portions of the sides and ends, thus making the transparent window portion of the package much larger than the laminated portion. The 'folds or'bends therefore, are not limited to the area which is laminated, or of double thickness.

It should be further understood that while an important feature of our invention is the transparent base sheet of full width, that is; extending all the way around the inside of the bag or wrapper, thus giving maximum protection to the contents of the package, it is possible when desired, to supply the base sheet not in full width, in order to make a portion of the side edges of the laminated sheet of single thickness, rather than double thickness, with the object of using less paper and for making a seam or joint at the back or bottom of the package which will be less bulky than when the base. sheet does extend all the way "to the edges of the opaque member.

We do not, therefore limit ourselves to a base 1. A laminated sheet comprising, a base member-of transparent glassine, a transparent wax coating covering one surface, its opposite surface having a transparent wax coating thereon, opaque glassin'e strips secured to the second coating at the opposite" side edges but spaced apart atthe center portion of the base member, whereby the two coatings of transparent wax render the center portion more transparent.

2; As an article of manufacture, a sheet of greaseproof and moistureproof glassine paper, both surfaces of said sheet having a coating of wax for imparting to said sheet a glossy finish, one surface of said sheet having strips of opaque glassine paper superposed thereon and spaced from the center lineof said sheet.

3. A .laminatedsheet for wrapping paper and bags, comprising a base sheet of ;transparent glassine paper, said base sheet being provided with a continuous thin film of transparent wax on both surfaces, a plurality of strips of opaque glassine secured on the upper surface of said base sheet and parallel to the side edges of said base sheet and spaced from each other, the film of wax on the upper surface of said base sheet serving as a. binder for securing said opaque strips on said base sheet, the coating of transparent wax on both surfaces of said base sheet serving to increase the transparency of the exposed portions of said base sheet.

THEODORE A. HODGDON. PAUL E. HODGDON.

Images