US2932385A

US2932385A - Multicompartment package with internal breaker strip

Info

Publication number: US2932385A
Application number: US569538A
Authority: US
Inventors: Bollmeier Emil Wayne; Leo F Vokaty
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1956-03-05
Filing date: 1956-03-05
Publication date: 1960-04-12
Anticipated expiration: 1977-04-12
Also published as: GB859434A; DE1186800B; CH377278A; JPS3926597B1; DE1227382B; FR75473E

Description

E. W. BOLLMEIER ETAL Filed March 5, 1956 ,477D /VE 5 MULTICOMPARTMENT PACKAGE WITH INTERNAL BREAKER STRIP April 12, 1960 u mm wm Wwf Y m mur 2 5 m wm M 6 ...m fm /f H w WF f f Wn@ m f X /w ,/N 6 I i HH -l W MULHCOMPARTMENT PACKAGE WITH INTERNAL BREAKER srRn Emil Wayne Bollmeier, Mendota Heights, and- Leo F.

Vokaty, New Canada Township, Ramsey County,

Minn., assignors to Minnesota Mining & Manufacturlng Company, St. Paul, Minn., a corporation of Delaware Y Application March s, 1956, serial No. 569,538 i Claims. (Cl. 20G-47) This invention relates to the packaging of liquid or plastic materials, and particularly to interreactive materials which, when mixed together, set up or cure to a heat-resistant, hard and tough state. The invention relates to the packaged products and in particular to the novel multicompartment package having an internal breaker stripv providing for removal at will of the bar rier between separate compartments of the package.

Various liquid or plastic components may be enclosed in the separate compartments of the package. Upon breaking of the interior barrier or barriers, Ithese components may then be eiectively mixed together by hand manipulation of the outer envelope of the package. While the; contents need not be reactive with each other, they maybe, and preferably are, interreactive either at room temperature or on the application of heat. A typical andvprefen'ed combination of reactive components comprises as a iirst material a liquid epoxy 4resin and as a second material a stable mixture of liquidV organic polysulde polymer and a tertiary amine activator for the epoxy resin. When mixed together, these two materials react exothermally and produce a heat-resistant, hard and tough resinous product which is particularly useful as an' electrical insulating material.

The invention will now be more fully described in connection with the accompanying drawing, in which:

.Figure 1 is a planview, and Figure 2 is a cross-sectional view, of a preferred form of our multicompartrnent package. 'FiguresS' and 4 illustrate, in cross-section, modiied forms of internal barriers inthe package of Figures 1 andy 2;

Figure 5 is a sectional View of an alternative type of multicompartment package;l n 'i Figures 6, 7 and 8 illustrate inAcross-section additional modifications of internal barriers; and

Figure 9 is a plan view of common edge portions of two `of the packages of Figure 1 during a typical conv tinuous process of manufacture.

The package 10 of Figures 1 and 2 is made of two sections 11 and 12 of thermoplastic polymeric film, heat sealed at the edges 13 to provide a hermetically closed envelope,v The two sides of the package are also heat sealed to the opposite surfaces of an interiorV breaker strip 15 Y.along a central area 14, thus separating the package 10 into `two compartments, oneof whichcontains, for example, a liquid epoxy resin, the other then containing curing agents and activators for the epoxy resin. The seal at the breaker strip is of sufficient strength to maintain complete separation of the reactive contents of the two segments of the envelope during all normal handling,l packaging, shipping and storing operations.`

TheY heat seal between the sections 11 and12 of thermo# plastic lm and the breakeristrip 15 is conveniently made-by a process involving passing one of thetwo sheet materials in strip form continuously over a roller having a narrow peripheral `heated area, passing the 2,932,385 Patented Apr. 12, 1(9 60 Y from the second of the partially heated rollers. Such a process is capable of providing a bond between the several surfaces which is fully as strong as the bond produced between the two identical outer sheet materials under heat and pressure, but only if the breaker strip is also identical in physical structure with Ithe outer sheets. In the present instance, the breaker strip being of dissimilar` physical structure is, surprisingly, found to adhere with considerably reduced force to the outer sheets. The continuous strip formed as above indicated is -then formed into separate two-compartment packages by sealing under heat and pressure the edges 13 as indicated in Figure 1 and separating the packages along the connecting edge seal. The liquid or plastic reactive materials are metered into the compartments thus provided just prior to completion of the peripheral seal.

In activating and using the package of reactive resinforming components just described, the two panels 11 and 12 are separately gripped at the central areas of one of the compartments and are jerked rapidly apart along the central seam 14, thus 4breaking the seal between ione or the other of the panels and the breaker strip 15 without damaging the permanent edge seal 13, and permitting the reactive contents to be combined within the envelope. Combination is effected by hand manipulation of the envelope and is continued until a homogeneousmixture is obtained and the reaction has commenced'. One corner of the envelope is then opened, for example by cutting along dotted line A of Figure 1, and the contents flow or are squeezed out into a waiting mold or other cavity as desired, where the reaction continues to completion.

From the application described, it will be apparent that the heat seal between the panels 11 and 12 and the breaker strip 15 must be substantially less strong than the heat seal between the panels themselves at the outer peripheral edge 13.

l It has been found that any attempt to produce a differential heat seal by pressing the two panels directly together at temperatures or pressures lower than those required to provide the rupture resistant edge seal 13, invariably results either in la strong seal which cannot readily be broken or in a weakseal which is incapable of maintaining the desired separation between the two compartments of the envelope. Evan though accurate control of temperature, pressure and time be achieved, the normal variations in thickness of extruded iilm, surface irregularities, .and other uncontrollable variations precludey the vrformation of such internal seals on any commercially useful basis.

We have now found that the insertion of a suitable breaker strip 15 between the tilm sections 11 and 12 overcomesthese difficulties and provides a package which is entirely resistant to accidental joining of the several compartments, while being easily activated by hand pulling whenever desired. Surprisingly, we have found thatfthe breaker strip may be identical in chemical composition with the outer iilms 11 and 12, the only necessary diference being a dierence in physical orientation or equivalent property.

As a preferred example, the envelope of Figures l and 2 is produced from polyethylene lm which has been produced by extrusion from a tubing die, and the barrier strip 15 is produced from a film of chemically identical polyethylene Vwhich has been extruded from a flat sheeting die, and to approximately the same thickness. The ma- 3 terials appear to weld together under heat and pressure to substantially the same degree, but it is found that the bond obtained between the two dissimilar films, while being entirely adequate to maintain separationl between the two compartments of the package during normal handling, is still readily broken by hand jerking or pulling on the two film walls of the envelope adjacent the center seal. kOn the other hand, the edge bond 13 is found to be completely resistant to such hand pulling, the film ordinarily breaking at some point removed from such bond when placed under suflicient stress.

Polyethylene film alone is somewhat lower in tensile strength than may be required for certain types of packages. The lm is desirably reinforced by laminating with another film, such as cellophane or polyester lm, or metal foil, or paper, which has much higher tensile strength, but is incapable of heat sealing. In such structure; the polyethylene surface of the composite film forms the inner surface of the envelope and the product is therefore identiiiable as a thermoplastic polymer film. IThe breaker strip is not laminated, but is composed entirely of polyethylene having a different physical orientation from that of the polyethylene layers of the films 11 and 12 forming the container.

The same results are obtained by reversing the two types of films, i.e., by employing for the envelope a lm which has been prepared by extrusion from a flat sheeting die, and for the breaker strip a film formed with a tubing die.

Equivalent results are obtained with envxelopes and breaker strips which are chemically different while still capable of forming an effective heat seal having less resistance to rupture than a heat seal of either material to itself. One example is an ethylcellulose-envelope with a breaker strip of plasticized nitrocellulose. Another is a polyethylene-lined envelope with a chlorinated rubber breaker strip. e

While the bond between the film and the barrier strip of the package of Figures 1 and 2 will ordinarily break along the plane of the initial juncture between the two, there may be at times some transfer of polymer from the breaker strip to the outer iilrn, or vice versa, when the package is activated. The modified structures illustrated in Figures. 3 and 4 provide for deliberate transfer of portions of the breaker strip to the outer films.

In Figure 3, the two films 31 and 32, corresponding with iilms 11 and 12 of Figure 2, are bonded to opposite sides of breaker strip 35 which consists of a central fibrous portion 33 and surface lms 36 and 37. Thesurface films are of the same composition as the envelope, and form with the. latter a heat seal which is equally as strong as the seal formed around the outer edges S13-of the envelope 10 of Figures. 1 and 2. The fibrous central layer 38 is suiciently strong to provide adequate resistance to ordinary handling, and is suiiiciently dense to prevent any appreciable transfer of liquid from one compartment of the package to the other. However thersection 38 provides a weakened plane at the center of the breaker strip, so that, when the sides of the package are jerked apart, the breaker strip splits along this central plane. The resulting two halves of the breaker strip remain attached to the respective sides of the envelope. YMixingrof the liquid or plastic components is then accomplished by hand manipulation as in the case of the envelope in Figures 1 and 2.

An example of a structure corresponding to that illustrated in Figure 3 employs as the breaker strip a Structure consisting of a thin porous paper coated on both surfaces with a thin continuous llayer of polyethylene which is heat scalable to' the polyethylene-lined outer envelope. The paper center remains'porous, any slight penetration by the reactive materials in the package resulting in the formation of an impervious resinous reaction prod- .uct` along one or the other of its exposed-edges.

f aeaasse Y breaker strip 45 a strip of polymeric material which is substantially softer and of lesser internal strength than the thermoplastic interior surface portion of the

films

41 and 42 of the outer envelope, to which it is heat sealed. Activation of the package byierking apart the

side walls

41 and 42 then results in a tearing away of a substantial portion of the breaker strip 45, as indicated by the dotted lines 46, the material remaining attached to one or the other of the envelope walls. Materials which have proven highly satisfactory in such a structure include high molecular weight polyethylene iilm envelopes and low molecular weight, but still solid, polyethylene breaker strips.

The structure'. illustrated in Figure 4 employs as the 75 The envelope structures thus far illustrated have been indicated as constructed of two separate sections of lm, sealed around the entire periphery as well as along the central area 14. The same results may be obtained by employing a single section of film, folding it along a centrol' line to form an edge, and then completing the envelope by heat sealing the remaining portions as necessary. A still further variation employs extruded tubular lm as the envelope, the breaker strip being inserted and sealed in place across a centralsection and the ends of the tube then being closed by heat sealing. The liquid or plastic contents are obviously introduced into their respective compartments prior to nal heat sealing, and may be introduced either at the end or at a side of the package, depending on the particular structure employed as well as other factors.

A somewhat different but closely analogous structure is illustrated in Figure 5. `In this example, the package 50 consists of a relatively'rigid but still flexible one-piece envelope 51 having an internal peripheral channel 59 into which is set a closely iitting and somewhat less flexible diaphragm 55 serving as a breaker strip. The package is activated by pressure applied to one end of the package or capsule, causing the diaphragm to be snapped out of its normal retaining channel, thus permitting mixing of the interreactive contents. The reactive mixture is then forced from the capsule through the tip 52 which is opened for this purpose by cutting along dotted line A.

The breaker strip or diaphragm 55 of Figure 5 is not required to be heat sealed to the walls 51 of theV capsule 50, but the relative rigidity of the structure, as compared withl the structures illustrated in the previous figures, produces substantially the equivalent effect. The liquid or plastic contents are prevented from intermingling prior to activation of the cartridge. Ihe breaker strip is effectively removed from its initial position by manipulation of the envelope when required, and by stresses which are' insufficient to cause damage to the outer envelope.

The breaker strip 65 of Figure 6 is formed of two layers66 'and 67 of thermoplastic film material of the same chemical but different physical structure. The two sections are lightly bonded together, e.g., by techniques. herein describedand the composite is bonded to the two outer iilms `61 and 62 forming the center seal ofthe package as'shown in Figure 1. When the package is opened, the breaker strip fails along the central interface, thus permitting the reactive contents of the two compartments of the package to be intermixed.

'Ihe packages of which the breaker strip and' adjacent portions are indicated in Figures 7 and 8 provide for the inclusion of a third reactive component within the breaker strip itself. In Figure 7, the breaker strip is in the form of a hollow thin sealed tube or cylinder, sealed along opposite paraxial areas to the

outer films

71 and 72. In this case the latter films are indicated as of composite structure, having an inner thermoplastic layer and an outer layer of increased strength. Such a film has already been described in connection with the descriptionof' the package in Figure 1. The thin film formingV the breaker strip 75 has sufficient thickness or body to permit the formation of a strong bond between it' andi the thermoplastic surfaces of the outer films', but isl much lower inftensile strengththanthe laminated films. When the latter are jerked apart, in using the package, the lm of the breaker stripV fails, thus liberating the reactive component initially contained` therein Y and also permitting mixing of the `reactive components of this and the other two chambers of the package.V

Another modification, illustrated in Figure 8, employs a tubular breaker strip 8S constructed of two strips 86 and 87 of -thin thermoplastic filmmaterial sealed to the'outer laminated Vlms 81 and 82 and to each other along the edges, but separated along the central areas to form a third compartment for reactive material. It will be apparent that the films 86 and 87 may be sealed to the outer sheets 81 and 82 along areas other than the sealed edge areas of the breaker strip `85. Since the films 86 and'87 are thinner and of lower tensile strength than the outer laminates, the breaker strip fails in the same manner as that of Figure 7, i.e., by tearing of the film material, and hence the several bonds between thermoplastic surfaces may be made as strong as desired. I

In all of these packages, it will be observed that the binder `strip provides an increased thickness at the outer edge of the package, i.e., at the corner 19 of Figure 1. Undersuch conditions it would normally be expected thatleakage would occur at such points due to insuicient bonding at the 'juncture between the breaker strip and the outer sheet materials. Surprisingly, the packages of this invention are found to be completely free of any such leakage, even after the package has been activated by jerking the outer panels rapidly apart along the central seam as hereinbefore described. It is believed that this result is accomplished in 4the following manner. As shown in Figure 9, the formation of a seal between the outer sheet materials to forma common edge of adjacent packages in a continuous strip of the film material results in a displacement of the thermoplastic polymer at the corner area 19, as indicated by the extension of the dotted line indicating the boundaries of the breaker strip 15. In the packages of Figures l and 2, 4, 6, 7 and 8, the thermoplastic breaker strip is effectively masticated `and integrated with the thermoplastic material of the outer film or laminate. In the structure of Figure 3, the thermoplastic material additionally penetrates and impregnates the fibrous layer 38. In all cases, there is produced a peripheral bond 13 which is no thicker at the corner area 19 than at any other point around the entire periphery of the package. The corner area is at least as well bonded as the remainder of the peripheral seal, and in many cases is found to have `a superior bond due to the additional sligh-t ridge of polymer along the inner edge of the peripheral seal, as at area a of Figure 9. As before indicated, cutting the seal along the central line c of Figure 9 severs the completed package from the adjacent package next in line in the continuous method of manufacture described.

This application is a continuation-in-part of the copending application Serial No. 386,992 of Emil Wayne Bollmeier and Leo F. Vokaty, led October 19, 1953.

What is claimed is as follows: l

1. A package comprising a hermetically closed envelope of thermoplastic polymer lfilm enclosing a hollow breaker strip of a thermoplastic polymer material having less internal strength than said lm, adherently heat sealed to said lm along a narrow line around the entire interior cross-section of said envelope, and itself providing a hermetically closed envelope interiorly of said package.

2. A multicompartment package comprising a hermeti- 6 under aV stress insuicient to break th'e adherent bond between 'the envelope and the surfaces of the breaker strip.`

3. The multicompartment package of claim 2 containing in one compartment a liquid resinous component and in another compartment, separated from said one compartmentY by lthe separable breaker strip,. another reactant material reactive with said liquid resinous material to produce `a heat-resistant, hard and tough resinous product. Y.

4. A multi-compartment package for a plurality of separately compartmentized inter-reactive miscible contents, comprising Van upper thermoplastic polymer film wall section, a coinciding lower thermoplastic polymer film wall section, and an intermediate narrow laminar breaker strip across the entire width of said wall sections and intermediate the ends thereof, said breaker strip being sealed along its entire length to corresponding opposing narrow areas of said wall sections to provide a disruptable barrier between the resulting two compartments of said barrier, and said breaker strip comprising a central disruptable porous fibrous layer having a thermoplastic polymer lm layer on each side thereof.

5. vA multi-compartment packageV as dened in claim 4 in which the opposing lateral edgev areas of said coinciding Wall sections are permanently sealed together to form outer edges of said package, the fibrous layer of said breaker strip remaining internally substantially free of the thermoplastic polymer film material between said sealed edge areas and being impregnated with said material within said edge areas.

6. A multi-compartment package for a plurality of separately compartmentized inter-reactive miscible contents, comprising a first thin flexible wall section having an inner exposed-surface thermoplastic polymer film and a reinforcing film laminated thereto, a coinciding second thin texible wall section having an inner exposedsurface thermoplastic polymer film and a reinforcing film laminated thereto, said inner' films being capable of being permanently sealed together under heat and pressure, and an intermediate narrow breaker strip across the entire width of said wall sections and intermediate the ends thereof and comprising a central thin fibrous layer having an exposed thin thermoplastic polymer film layer on each side thereof, welded along opposite central flat surface areas of said strip to each of said wall sections along the full width of the inner surface of each said wall section.

7. A multi-compartment mixing-package for a plurality of separately compartmentized miscible contents, comprising a rst thin strong liexible thermoplastic polymer film wall section, an opposing coinciding second thin strong 'flexible thermoplastic polymer film wall section, said sections being capable of being permanently sealed together under heat and pressure, and an intermediate narrow breaker strip across the entire width of said wall sections and intermediate the ends thereof, adherently heat sealed along opposite central -iiat surface areas of said strip to each of said wall sections along the full width of the inner surface'of each said Wall section and providing a compartment-separating seal capable of being broken by hand pulling on said opposing wall sections.

8. A multi-compartment mixing-package for a plurality of separately compartmentized miscible contents, comprising a first thin flexible wall section having an inner exposed-surface thermoplastic polymer film and a reinforcing lm laminated thereto, a coinciding second thin flexible wall section having an inner exposed-surface thermoplastic polymer film and a reinforcing film laminated thereto, said inner films being capable of being permanently sealed together under heat and pressure, and an intermediate narrow breaker strip across the entire width of said Wall sections and intermediate the ends thereof, adherently heat sealed along opposite central at surface areas of said strip to each of said wall sections '7 along the full width of lthe inner surface .of :each said wall section; said breaker striprcomprising a laminar web material readily separable into two laminae along Vlan interior plane and providing a compartment-separating seal ycapable of being broken by hand pulling on said opposing wall sections.

9. A multi-compartment mixing-package for a plurality of separately compartmentized mis'cible contents, comprising a :rst thin flexible Wall section havingva'n inner exposed-surface thermoplastic polymer 4film and a reinforcing film laminated thereto, a coinciding second thin ilexible wall section having an inner .exposed-surface thermoplastic polymer tilm and a reinforcing ilm laminated thereto, said inner lilms being capable .of rbeing permanently sealed together under heatand pressure, and an intermediate narrow breaker vstrip across .the `entire width of said wall Vsections and intermediate .fthe ends thereof, adherently heat sealed alongop'osite central at surface areas of said strip to each of said wall sections along vthe full width of the inner surface .of each'said wall section; said breaker strip being va strip 4of thermoplastic polymer material having Vless internal strength than said wall sections and providing a compartment-separating seal capable of being brokenby hand'pulling on said opposing wall sections.

:10. A multi-compartment mixing-package for a plu; l

rality of separately compartmentized miscible contents, comprising a rst thin exible wall section having Van inner exposed-surface thermoplastic polymer lrn and a reinforcing lilm laminated thereto, a coinciding second thin ilexible wall section having an inner exposed-surface thermoplastic polymer lm and a reinforcing 'lm laminated thereto, said inner films being capable of being permanently sealed together under heat and pressure, and an intermediate narrow breaker strip Vacross the entire width of said wall sections and intermediate the ends thereof, welded along opposite central flat surface areas of said strip to each of said wall sections along'the ,full width of the inner surface of each said wall sectionysaid breaker strip consisting of two layers of thermoplastic ilm material lightly bonded together and providing a compartment-separating seal capable of being broken by hand pulling on said opposing wall sections.

References Cited in the le of this patent UNITED STATES PATENTS 2,245,738 Taylor June 17, 1941 2,560,535 Allen Iuly17, 19,51

2,605,896 Rohdin Aug. 5, 1952 FOREIGN PATENTS 711,186 Great Britain June 23. 1954

Claims

1. A PACKAGE COMPRISING A HERMETICALLY CLOSED ENVELOPE OF THERMOPLASTIC POLYMER FILM ENCLOSING A HOLLOW BREAKER STRIP OF A THERMOPLASTIC POLYMER MATERIAL HAVING LESS INTERNAL STRENGTH THAN SAID FILM ADHERENTLY HEAT SEALED TO SAID FILM ALONG A NARROW LINE AROUND THE ENTIRE INTERIOR CROSS-SECTION OF SAID ENVELOPE, AND ITSELF PROVIDING A HERMETICALLY CLOSED ENVELOPE INTERIORLY OF SAID PACKAGE.