Process in the manufacture of flexible containers

Oct 18, 1966

PROCESS IN THE

e. w. platt 3,279,331

MANUFACTURE OF FLEXIBLE CONTAINERS

Filed July 1, 1964

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TIC. 1

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fig. 4

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FIG. 5

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United States Patent Office _{Patenled Oct}.’ ₁₈,₁₉₆₆

3,279,331

PROCESS IN THE MANUFACTURE OF FLEXIBLE CONTAINERS

Eric W. Platt, 14 Harcourt St, New Farm, Brisbane, Queensland, Australia

Filed My 1, 1964, Ser. No..379,616 Claims priority, application Australia, July 8, 1963, 32,776/63

Claims. (Cl. 93—35)

This invention relates to an improved flexible container and the process in its manufacture, and is particularly· directed to a rapid and efficient method of separately sealing, unsealing, and resealing the mouth opening of each of a number of separate bag units which go to make up the ; flexible container.

The paper bag has been in use· for many years as a means for packaging goods for carrying purposes. Following the recent development of plastic material there have been occasions when it has been found preferable to replace a paper bag with one constructed from a thin sheet of polyvinyl chloride or some other suitable plastic substance. The use of a plastic bag introduces the acceptable properties of added strength and transparency, and has the definite advantage over a paper bag in that it may be used for the carriage of liquid, a use to which a paper bag cannot be satisfactorily applied.

In the known construction of paper bags, and in the more recent construction of plastic bags, no provision appears to have been made for a rapid sealing of the bag opening to retain the goods therein; a rapid unsealing of the bag opening to remove some of the goods therefrom; and a rapid resealing of the bag opening after some of the goods have been removed therefrom to retain the remaining goods in closed condition within the bag.

It is the principal object of the present invention to meet the above weakness revealed in present day flexible bag construction.

Other objects of the invention will become apparent as the description proceeds.

In accordance with the present invention I provide a method for the construction of flexible containers, said method consisting of the process of selecting a rectangular sheet of flexible material considerably greater in length than in width; folding the sheet about a longitudinal axis to enable the two side edges to lie in proximity to one another; applying one or more narrow strips of adhesive substance over the surface of the folded sheet, each strip extending for the full length of the flexible material; sealing the end edges of the folded sheet to form a long flexible container; applying a number of intermediate seals to divide said flexible container into a number of individual bag units each having a mouth opening which may be sealed and resealed by the application of finger pressure to the adhesive substance.

One specific method of application of this invention consists in the process of selecting a rectangular sheet of fluid impermeable flexible material having predetermined length and width; folding said sheet about its mid-axial line such that its two side edges meet; inwardly folding each of the meeting side edges to form a pair of inturned lips of equal width along the mouth edge of the container; applying a fluid impermeable seal along the open end edges of the container formed from folding the sheet of flexible material; applying a fluid impermeable seal at spaced intervals across the width of the folded container to divide it into a number of individual bag units; forming a fluid impermeable adhesion between the confronting surfaces of the inturned lips, said adhesion being limited to the extent of providing a narrow opening to receive a length of tubing for the admission or withdrawal of fluid or granular substance into or from each individual unit;

resealing the opening after the fluid or granular substance has been admitted or withdrawn from an individual unit of the container; and forming perforations extending within the length of each seal dividing the container into a number of individual units to separate each bag unit from the container as desired.

In applying this invention to paper bag construction, the seals at the end edges of the container, and the intermediate· seals dividing the container into a number of individual bag units, are formed by the use of any well known strongly binding glutinous material.

When applying this invention to the construction of a flexible plastic container it has been found preferable to form the rectangular sheet from polyvinyl chloride. As this is a thermoplastic substance, the seals at the end edges of the container and the intermediate seals dividing the container into a number of individual bag units may be formed by the application of heat or high frequency current to the outer surface of the folded sheet.

When applying the intermediate seals to divide the flexible container into a number of individual bag units, it is preferable to form a tear strip down the centre of each of the intermediate seals. This tear strip permits easy detachment of bag units from the container length, and may be constructed of any well known form, such as a strip of weakened material, or a line of perforations.

It has been found convenient to support the container length by winding it around the outer surface of a roller housed within a dispenser. When it is desired to sever a bag unit from the container it is only necessary to unwrap the required length of container from the roller to the extent of bringing its tear strip into contact with a sharp edge located along one side of the dispenser. _

Although for general purposes the seal dividing the ; container into separte bag units is formed as a straight sealing strip, for novelty and advertising purposes, the side edges of the dividing seals may be curved to present a series of bag units shaped into the form of animals, clowns, or other novelties particularly appropriate as a method ) of drawing public attention to the virtues of the substance within the bags.

The narrow strip or strips of adhesive substance over the surface of the folded sheet may be applied thereto in a number of different ways. One method is to have a surface layer of suitable adhesive material directly sprayed onto the sheet. A second method is to utilize a double sided adhesive tape, one side adhering firmly to the surface of the folded sheet and the other side providing the desired sealing and resealing facilities across an opening in the container. A third method is to utilize a single sided adhesive tape. One section of the width of this single sided adhesive tape adheres to the surface of the sheet adjacent the edge of an opening into the container, whilst the other section of the tape width forms a tongue which extends slightly into the opening and thereby serves as a strip for sealing and resealing the opening. A fourth method is to fold the width of a long double sided adhesive strip over the end edge of an inner wall of the contaner. In this latter method a sealing strip is provided which is double acting in that it serves to seal and reseal openings on either side of the wall.

On each occasion when a double sided adhesive tape is employed it may be expedient to supplement the grip of the tape over the surface of the folded sheet by the addition of a slightly stronger adhesive substance at spaced intervals along its length. This would expel any chance of the tape being pulled away from the surface of the container when applied as a seal across openings within the container.

When forming the container it has been found convenient under certain circumstances to extend the end edges of the container walls slightly beyond the outer side

3,279,331 edges of the strips of adhesive substance. This enables tabs to be formed which serve to provide finger gripping means at positions in proximity to the sealable opening. To break the seal formed by the adhesive substance across the opening, an outward pull is applied manually to these tabs.

It has been found in practice that a container having a sealing strip applied thereto in the manner as revealed in this specification can be rapidly and tightly sealed and resealed at least thirty times without losing any power of adhesion from the adhesive material.

The container, together with each of the bag units formed from this container, may be constructed of a par^tla. ^ar _^cross^sectional shape depending upon the use to which it is to be applied. A number of suitable shapes will now be described by reference to FIGURES 1 to 14 of the accompanying drawing.

Referring to FIG. 1, the initial fold of the rectangular sheet is formed about a mid-axial line, and the mouth of the container is provided between a pair of inturned lips 1 . A pair of matching double sided adhesive tapes 3 4 pass over the two facing surfaces of the inturned lips ’ In this type of construction, by the use of fluid impermeable polyvinyl chloride sheeting as the substance forming the container, the mouth opening may be sealed to retain 25 liquid therein, and may be unsealed to the extent of providing a narrow opening to receive a length of tubing for the passage of liquid to or from the container. A liquid container of this form has the advantage that owing to its face. In addition, the pressure of any liquid or granular substance passing into the pockets 5, 6, formed by the mturned lips will assist to retain the seal over the mouth opening of the container. The use of a pipe or a straw 35 m^Str ^tO- ^{PaSS liquid into the} container and withdraw the liquid from the container serves to pre^v“i tbe retention of liquid over the adhesive surfaces which under some circumstances may result in a deteriora? tion of the holding power of the adhesive surfaces bi FIG. 2 a single inturned lip 7 is formed adjacent the ^contamer formed by the flexible sheet The end edge of the straight side 8 of the container extends slightly beyond the mouth opening to form a tab which enables an easy grip to be obtained to assist in un- 45 sealing the container mouth. The adhesive material for ^C°^sare °^{f the} mouth opening consists of a strip of single sided adhesive tape with the width section 9 having its adhesive surface firmly attached to the inner surface of the mturned lip 7, and the width section 10 depending below the lower edge of the inturned lip 7 to enable the closure of the mouth opening when .the adhesive surface s^herTJ^{00 10} ?^ngages ‘be inner surface of the side vantase^hat^A^^rMi⁶¹’ rT-i”'⁸ construction has the ad- ·—* ui uouoie siaea adhesive tape material .771 °' “ may be desired to package a granular substance within this iorm of container construction and withdraw it without any contact with an adhesive layer. This may be effected y fornung a vertical slit through the tape widths 9 10 ^a^dext“^dlng this slit through the wall of the inturned terial frnm^^{0 Γ}ί™^{ί8 a dis}charge of the material from the container through the slit in the intumed p when the mouth of the opening is unsealed, and a drawfafe 10 s^R°fV^he °^{f δΙίί when adh}esive sur- 65 lace 10 seals the mouth opening.

*ⁿ construction is very similar to that of

1G. 2 with the exception that the straight side of the container is lengthened slightly to form a sealable lid which has a downward fold. 11. The end of this downward 70 fold is formed with an intumed lip 13 to permit the hous“⁸ [be lower portion of a double sided adhesive tape 12. The inwardly facing surface at the upper section of the tape 12 permits the end of the lid to be seated against the outer wall face of the container, and the inturned lip 75 provides means for gripping the lid when it is desired to break the seal. The additional compartment formed by the lid may serve as a storage for any implements or materials desired to supplement the main body of material within the container.

In FIG. 4 the seal of the mouth of the container is effected by a strip of double sided adhesive tape IS having one side attached to the inner surface face of the container and extending adjacent the edge of a container wall which assists in the formation of the mouth opening. The other side wall of the container is extended beyond the mouth opening into a downward fold 16 to serve as a lid for the container which has an inturned end to receive a further strip of double sided adhesive tape in a identical ^to that described with reference to FIG. 3.

The form of folds illustrated in FIGS. 5 and 6 again consists of a container having one side wall upwardly extending to assist in the formation of a mouth opening, and the other side wall extending beyond the mouth opening into downward folds 18, 19, to serve as container lids, hi the embodiment of the invention as illustrated in FIG 5, a double sided adhesive tape 20 is bent over the upper end edge of the upright container wall 20α. This tape is *^iiached ^to. ^b°th ^sides of wall 20α. On account of the bend in this adhesive tape it may serve the dual purpose of sealing the mouth opening by bringing the opposite walls of the container into adhesive engagement ^and„^a!s? ^ssrves as a means for sealing outer surface of the container wall 20a. In FIG. 6 the upright wall 22α is provided with an inturned lip 22 over which the double sided adhesive tape 21 is attached to lorm the dual purpose seal.

The form of fold illustrated in FIG. 7 is particularly acceptable in cases where it is desired to include a sealab e pocxet above the container to house material suitable tor use in association with the material within the container closure. If the container enclosure includes a soft drink, the .pocket may contain a drinking straw, or it may contain flavoring essence to mix with the liquid ¹1 ^c°^{ntainer t0} form a cocktail mixture The sealable pocket may provide a housing for advertising matter serving to advance the sale properties of the prod. uct included within the container. The pocket 23 may house a drinking straw 24 and the wall 25 of the container serves to divide its mouth portion from the pocket 23 SenZ^a“t f°^{f the c}°ⁿ,^{taincr is} extended beyond the mouth openm₀to form a lid with a downward fold portion 27 ' ,ίσηΐ a^D'^{S Of} ,^{the container} mouth opening and the seal^f a ftrin^{6 P}r°?^keL²³ ?! ^e,^{ffected b}y dual functioning of a strip of double sided adhesive tape 28 bent to pass around the upper edge of the container wall 25. A fur^of_f^doub!® ^s‘^ded adhesive tape 29 is attached the lid. ---------- ^±uld portion 27 of ve^Hnn¹^ ^{8 ther}f -^{S ni}“^strated application of the invention to a container formed as a single fold. In this form of fold the side walls 30, 31 of the container ex Se^Sf?Tr ^b7°^{nd the mouth openin}S to provide adeft?dedred^n^{S ίθΓ n}’^a™^alIy «ripping the container when slated tL “T^6a ? · ^m°^{Uth opening after k} bas been ^ed· Tbe sealing stop 32 is a double sided adhesive t^ie attached to the inner surface of the container wall 31 adjacent the mouth opening. This form of container and bTa unhs^may '^{be ad}.^{apted to paper} containers of plasfic s£eXZ “ ^{bag U}“^{tS formed}

In FIG. 9 the fold is very similar to that of FIG. 8 with the exception that the lower wall of the container is formed with a depending lip 34, and a double sided adhesive strip 35 is attached to the outer face of this lip o seal the mouth of the container against the opposin’ wall under linger pressure applied to the outer surface of the container. This fold has an advantage over that illus3,279,331

Ο trated in FIG. 8 in that the grip of the seal across the mouth of the container may be supplemented by the pressure of some of the goods within the container.

In FIG. 10 there is illustrated a form of container which is initially closed by heat sealing the two surfaces 5 36, 37 together. A pocket 40 is formed over the upper surface of the container. This form of container may well be utilized as a carrier for fruit drinks, and a straw with a pointed end may be housed within the pocket opening^ which is sealed by a double sided adhesive strip 38 which brings the two inner side wall surfaces of the pocket into sealed engagement with each other. When it is desired to withdraw drink from the container, the pocket opening is unsealed, and a hole is punctured through the floor of the pocket with the pointed end of 15 the straw. The straw is used to suck a desired amount of the drink from the container which is closed by rescaling the pocket opening.

In FIG. 11, a folded container construction similar to that illustrated n FIG. 9 is provided with the exception 20 that the double sided adhesive tape 41 is provided over the inner surface of the wall 42 of the container.

FIG. 12 is a modification of the fold construction illustrated in FIG. 7 in that a single sided adhesive tape 43 is provided depending from the inside surface of one of 25 the side walls of the container to seal the mouth opening; a pocket 45 is provided to house matter which may be relevant to that supported within the container, and a double sided adhesive strip 44 is provided to seal the end of a lid formed by the folded extension 46 to the other 30 side wall of the container. To obtain access into the container the lid is opened by manually 'breaking its seal, and the seal at the mouth of the container is then likewise broken. On removal of a desired quantity of material from the . container it is resealed at the mouth opening 35 and the lid portion is again resealed adjacent its end.

FIGS. 13 and 14 illustrate means for adapting this invention to a plastic container or a bag unit formed from this container for the purpose of displaying an attractive variety of goods to their best advantage. In 40 this construction the mouth opening is formed over the rear surface of the container or bag which would be generally hidden from the sight of the general public when on display.

. In FIG. 13 the mouth opening is sealed by an upturned ,lip 48 having an outer surface which engages the outer face of a double sided adhesive tape 49 fixed to the inner surface of the container wall 50. When it is desired that articles be removed from the bag or container the seal is manually broken, and the bag or container is resealed by finger pressure. ™

FIG. 14 varies the construction of FIG. 13 in that the upturned lip is dispensed with. A double sided adhesive tape 51 is formed over the outer surface wall 52 of the container. qWhilst no reference has been made in the specification to adhesive tapes of any specific colour, it is to be understood that tapes in various colours are available and a most suitable colour for use with the adhesive materials would be dependent upon the particular class of goods 60 to be merchandised.

A method of construction in accordance with this invention has extensive advantages over containers employed at the present time in the packaging of small goods or relatively small quantities of liquid. These are exem- θ⁵piffled by the speed in which a bag may be sealed, and the fact that some of the goods may be removed from the bag while the remaining goods are retained within the bag which may be sealed some thirty or more times with- γθ out any noticeable reduction in the holding power of the seal.

Whilst various embodiments of this invention have been disclosed in the foregoing description I desire that it be fully understood that the limitation to the scope of this 75 : invention is determined solely by the extent of the limitation imposed by the following claims: twisting, turning