US3475246A - Heat sealed pull tab - Google Patents

Heat sealed pull tab Download PDF

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Publication number
US3475246A
US3475246A US617405A US3475246DA US3475246A US 3475246 A US3475246 A US 3475246A US 617405 A US617405 A US 617405A US 3475246D A US3475246D A US 3475246DA US 3475246 A US3475246 A US 3475246A
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US
United States
Prior art keywords
lid
tab
pull tab
container
heat
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US617405A
Inventor
Stafford D Collie
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Huhtamaki Consumer Packaging Inc
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Phillips Petroleum Co
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Priority to US408281A priority Critical patent/US3321123A/en
Application filed by Phillips Petroleum Co filed Critical Phillips Petroleum Co
Priority to US61740567A priority
Application granted granted Critical
Publication of US3475246A publication Critical patent/US3475246A/en
Assigned to SEALRIGHT CO., INC. A DE CORP. reassignment SEALRIGHT CO., INC. A DE CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: PHILLIPS PETROLEUM COMPANY A DE CORP.
Anticipated expiration legal-status Critical
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/74Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by welding and severing, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area
    • B29C65/743Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by welding and severing, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area using the same tool for both joining and severing, said tool being monobloc or formed by several parts mounted together and forming a monobloc
    • B29C65/7441Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by welding and severing, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area using the same tool for both joining and severing, said tool being monobloc or formed by several parts mounted together and forming a monobloc for making welds and cuts of other than simple rectilinear form
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C59/00Surface shaping of articles, e.g. embossing; Apparatus therefor
    • B29C59/007Forming single grooves or ribs, e.g. tear lines, weak spots
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/18Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112Single lapped joints
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/11Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
    • B29C66/112Single lapped joints
    • B29C66/1122Single lap to lap joints, i.e. overlap joints
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/01General aspects dealing with the joint area or with the area to be joined
    • B29C66/05Particular design of joint configurations
    • B29C66/10Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/13Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/131Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/50General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/53Joining single elements to tubular articles, hollow articles or bars
    • B29C66/534Joining single elements to open ends of tubular or hollow articles or to the ends of bars
    • B29C66/5346Joining single elements to open ends of tubular or hollow articles or to the ends of bars said single elements being substantially flat
    • B29C66/53461Joining single elements to open ends of tubular or hollow articles or to the ends of bars said single elements being substantially flat joining substantially flat covers and/or substantially flat bottoms to open ends of container bodies
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/80General aspects of machine operations or constructions and parts thereof
    • B29C66/81General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps
    • B29C66/814General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/8145General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the constructional aspects of the pressing elements, e.g. of the welding jaws or clamps
    • B29C66/81457General aspects of the pressing elements, i.e. the elements applying pressure on the parts to be joined in the area to be joined, e.g. the welding jaws or clamps characterised by the design of the pressing elements, e.g. of the welding jaws or clamps characterised by the constructional aspects of the pressing elements, e.g. of the welding jaws or clamps comprising a block or layer of deformable material, e.g. sponge, foam, rubber
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/80General aspects of machine operations or constructions and parts thereof
    • B29C66/83General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
    • B29C66/832Reciprocating joining or pressing tools
    • B29C66/8322Joining or pressing tools reciprocating along one axis
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D17/00Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions
    • B65D17/28Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness
    • B65D17/401Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness characterised by having the line of weakness provided in an end wall
    • B65D17/4012Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness characterised by having the line of weakness provided in an end wall for opening partially by means of a tearing tab
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00General aspects of processes or apparatus for joining preformed parts
    • B29C66/70General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2577/00Packages formed by enclosing articles or materials in preformed containers, e.g. boxes, cartons, sacks, bags
    • B65D2577/10Container closures formed after filling
    • B65D2577/20Container closures formed after filling by applying separate lids or covers
    • B65D2577/2041Pull tabs
    • B65D2577/2058Pull tabs attached to the closure
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2577/00Packages formed by enclosing articles or materials in preformed containers, e.g. boxes, cartons, sacks, bags
    • B65D2577/10Container closures formed after filling
    • B65D2577/20Container closures formed after filling by applying separate lids or covers
    • B65D2577/2075Lines of weakness or apertures
    • B65D2577/2091Lines of weakness or apertures in cover
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T156/00Adhesive bonding and miscellaneous chemical manufacture
    • Y10T156/10Methods of surface bonding and/or assembly therefor
    • Y10T156/1052Methods of surface bonding and/or assembly therefor with cutting, punching, tearing or severing
    • Y10T156/1082Partial cutting bonded sandwich [e.g., grooving or incising]

Description

Oct. 28, 1969 s. D. COLLIE 3, 75,24

HEAT SEALED PULL TAB Original Filed Nov. 2, 1964 3 Sheets-Sheet 1 FIG.

INVENTOR. S. D. COLLIE A 7' TORNE KS Oct. 28, 1969 s. o. COLLIE 3,475,246

HEAT SEALED PULL TAB Original Filed Nov. 2, 1964 3 Sheets-Sheet INVENTOR. s. D. COLLIE BY I A 7" TOR/VEYS 1969 s. D. COLLJE 3,,475246 HEAT SEALED PULL TAB I Original Filed Nov. 2, 1964 3 Sheets-Sheet Z lLl/I/I/I/I/I/l/l/l/I //I l l// I [/1] F G 3d INVENTOR. S. D. COLL! E A TTORNEYS United. States. Patent 3,475,246 p 'HEAT SEALED PULL TA Stafford D. Collie, Kansas City,' Mo., assignor to Phillips Petroleum Company, a corporation of Delaware Original application Nov. 2, 1964,,Ser. No. 408 ,2 81, now a Patent N0.r3,321,123, dated May 23, 1 967. Divided and this application Feb. 20, 1967, Ser..No. 617,405

. Int. Cl. B2'9c 27/06; B321) 31/20 applying pressure to the pull tab; heating the bottom survface of the plastic lid thereby causing the pull tab to be heat-sealed to the lid. The tab can be key-shaped thus producing a key-shaped opening in the lid when the tab is removed. I

This is a division of application Ser. No. 408,281, filed Nov. 2, 1964, now Patent No. 3,321,123.

The present invention relates to sealed thermoplastic containers. In one aspect it relates to those thermoplastic containers which can be opened to permit the removal of the contents Without requiring the use of special implements. In another aspect, the invention relates to a heat-sealed pull tab which may be applied to the top of said container whereby the tab forms a shaped opening in the lid when it is peeled therefrom. In yet another aspect, the invention relates to thermoplastic containers .which are opened by tearing a plastic pull tab material along a predetermined line or region without the need of .any implement or tool. In yet another aspect this invention relates to a novel method for applying a pull tab to the lid of the container whereby the pull tab will form an opening in the lid when it is pulled or peeled therefrom.

In recent years there has been a trend toward the packaging of solid and liquid materials in thermoplastic containers. Suchcontainers-are more commercially desirable 1111311111086 containers previously made from cardboard, paper, metal and the like in that they can be molded into attractive shapes. These thermoplastic containers are formed with the lid produced separately from the body of the container, and after the body of the container is filled with a particular type of liquid material, the plastic lid is then applied by known heat-sealing methods to the open end of the container. In order to provide access to the contents of the container, it was necessary to be able to punch a hole in the plastic lid. Pull or rip tabs have been extensively used in forming such holes in the tops of metal containers; however, when this means was employed for plastic containers, the prior art experienced considerable difficulty in its attempt to provide a satisfactory tab opener which'eifected a rupturing or tearing of a hole in the plastic lid rather than the tab itself.

Moreover, the tab, although readily and conveniently removed merely by lifting or peeling it from the plastic lid, had to be sufficiently rugged towithstand the temperatures and treatment to. which said merchandise would be subjected so as not to cause a leak in the container.

One of the objectssof the present invention is to provide a novel pull tab opening means for thermoplastic containers which effects a rupturing or tearing of the hole in the plastic container rather than in the tab itself.

Another object is to provide a method of making a' package or container of thermoplastic material embodying novel means for enabling a person to readily open the package.

Yet another object of the invention is to provide a method for applying a pull tab to a thermoplastic lid for a container whereby the pull tab fills a shaped opening in the lid of the container, thereby making it possible to maintain a hermetic seal within the container.

A further object of the invention is to provide a novel method of making a unique form of pull tab which is suitable for application to containers made from thermoplastic materials, and to provide such a method which can be used in conjunction with the application of the pull tab itself to the plastic container.

A further object of the invention is the provision of a novel heat-sealed pull tab for producing an opening in a plastic container lid positively and expeditiously which results in requiring the expenditure of a minimum of effort on the part of the user in lifting the tab and pulling the same off the container wall.

A still further object of the present invention is the provision of a heat sealed pull tab which is made an integral part of a plastic lid portion of a container and the lid portion is sealed to the container with the pull tab attached thereto.

A still further object of the present invention is to provide a thermoplastic container having a seal, although readily and conveniently removed merely by lifting or peeling off the tab in the manner aforesaid, sufficiently rugged to withstand the temperatures and treatment to which such merchandise is ordinarily subjected.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same become better understood by reference to the following detailed description which is considered in connection with the accompanying drawings wherein:

FIGURE 1 shows a diametric view of the container of the present invention as it would be merchandised;

FIGURE 2 shows a view similar to FIGURE 1 i1- lustrating the removal of the pull tab from the lid of the container;

FIGURES 3a to 3d illustrate by way of example, the steps of the process of the subject invention in securing the pull tab to the lid of the container;

FIGURE 4 shows a diametric view of the underside of the pull tab after it has been removed from the lid;

FIGURE 5 shows a diametric view of the lid showing another embodiment in the method of securing the tab thereto.

This invention teaches a novel method for applying a pull tab to a plastic lid for a container in such a manner that the plastic in that portion of the lid immediately beneath the tab is structurally weakened so that it will adhere to the tab upon the tab being peeled or pulled from the top surface of the lid whereby an opening is conveniently formed in the top of the container.

The invention will be described hereinafter as applied to a bag or container having at least its lid portion consisting of thermoplastic material, but it will be understood by those skilled in the art that the pull tab of the invention can be applied to a wrapper for any object, regardless of size or shape.

More particularly in describing the invention, in FIG- URE l, is shown a container 1 comprising a body 3 and a lid 5. The container may be made of any suitable flexible thermoplastic material, such as a vinyl plastic or polyethylene, or other polymeric, plastic material, or of a paper material coated with a flexible thermoplastic coating.

A thermoplastic pull tab 7 is sealed to the lid 5 with heat and pressure according to a process hereinafter described. Although the pull tab may take various shapes,

the key hole shape represented in the drawings is preferred. The body of the pull tab is formed near the pe-- riphery of the lid with a curved edge 9a defining the face thereof, and an elongated edge 9b extending from this curved edge toward the center of the lid. This edge 9b facilitates the removal of the tab from the lid. The lid should be sufiiciently flexible to permit the tab to be lifted away from the surface of the lid and to permit the tab to be peeled ofi; however, it is also desired that it have sufficient firmness and toughness to form a rigid cover for the container capable of withstanding really rugged handling.

One method which may be used for carrying out the invention is that described in FIGURES 3a and 3d, in which there is shown a rubber mat 10 having a raised nipple 12 integral therewith, the nipple is substantially of the same design as the opening in the lid 5. A steel ruled die 11 in this preferred embodiment takes the shape of a key hole having a sharp curved edge 11a defining the base thereof and an elongated edge 11b extending therefrom. This steel rule die is then glued to the rubber mat in such a manner that the die surrounds the nipple causing it to protrude above the edges of the steel die. The plastic tab 7 is then centered over the steel die and the topside of the plastic lid is then centered over the pull tab as shown in FIGURE 3.

A Teflon covered heating head 13 having a source of heat (not shown) is applied to the under side of the plastic lid 5. This lid is then pressed down onto the rubber mat causing the rubber nipple which extends above the edges of the steel die, to become compressed thereby pushing the tab against the top side of the lid which has been weakened by the application of heat on its under side from the head 13. This action of heat and pressure bonds the tab to the lid. At the same time the lid comes into contact with the sharp edges 11a and 11b of the die 11 which causes the plastic lid to be weakened structurally along the contour of these edges. As a result the bond between the tab and the lid is stronger than that portion of the plastic lid which comes into contact with the sharp edges of the aforesaid die. Another important feature of this invention is that the heat is applied to the under side of the lid. Thus even if the container lid and the tear tab are of the same material and of the same thickness, the lid, not the tab, will tear because it receives more heat and is preferentially softened. By varying the amount of heat and pressure, it is possible to control the amount of pull required to remove the tab from the lid. The more heat and pressure, the easier it becomes to remove the tab. The temperature applied depends on the melting point of the polymer; however, the temperature can be raised considerably if the time and pressure variables are reduced.

For example, a tab of 18 mils thickness was heat sealed to a lid of 13 mils thickness at a temperature of 250 F. with a pressure of approximately 100 pounds/ square inch and a dwell time of 1 /2 seconds was suitable.

It is to be noted that the pull tab of the subject invention differs from the tear strip method of opening thermoplastic bags in that the tear strip must be of a heavier and stronger material than the bag itself whereas the effectiveness of the subject invention is dependent upon the heat and pressure, not the thickness of material used. It is possible to employ a tab being considerably lighter and weaker than the material from which the lid is made.

When the pull tab has been heat sealed to the lid as set forth hereinabove, the lid may be applied to the container according to conventional methods. When it is desired to open the container to provide access to the contents, the tab 7 is lifted away from the surface of the t" lidS along the edge 9b and then grasped with the fingers and peeled off.

The lid, having been previously weakened along a line which followed the contour of the edges of the die used in applying the tab to the lid, is fractured along this line so that as a result that portion of the lid sealed to the tab remains intact therewith and leaves an opening in the tape of a key on the lid. Because of the manner in which this tab was applied to the lid, its removal occurs cleanly without forming jagged edgesaround the key hole.

In another embodiment (see FIGURE 5) one end 15 of tab 7 is positioned over the nipple 12. Heat and pressure are once more applied to the lid 5 as described hereinabove so that only the end 15 of the tab 7 is sealed to the lid. When this tab 7, after being sealed in this manner, is pulled from the lid it will pull that portion of the lid which has been weakened by the heat and pressure through the combined action of die 11 and nipple 12 along with it, thereby creating an opening in the lid.

In the foregoing, the invention has been described with reference to a specific illustrative device and method. It will be evident, however, that modifications and variations, as well as the substitution of equivalent elements and steps of those described for illustration, may be made without departing from the broader scope and spirit of the invention as defined by the appended claims. Specification and drawing are to be regarded in an illustrative rather than a restrictive sense.

I claim:

1. A process for forming an opening in the thermoplastic lid, comprising the steps of bringing a pull tab also consisting of a thermoplastic material in contact with a portion of the plastic lid on the top surface thereof; applying pressure to the top surface of said portion of the lid; applying heat to the bottom surface of said portion of the lid, thereby causing the pull tab to be heat sealed to the said portion of the lid and also causing the said portion of the lid to become sufiiciently structurally weakened so that when the pull tab is removed this portion of the lid will remain attached to the pull tab and thereby cause an opening to be made in the lid.

2. The process according to claim 1 wherein said lid and said tab are polyethylene, said tab having the shape of the desired opening and said pressure is applied directly to said pull ta'b as'heat is applied directly to the bottom surface of the lid thereby causing the pull tab to be heat sealed to the said portion of the lid and causing the said portion of the lid to be sufficiently structurally weakened along the outer periphery of said pull tab.

3. The process according to claim 2 wherein said pull tab is key shaped and said pressure is applied along a line forming a closed key-shaped loop.

4. A process according to claim 1 wherein a heating head having a heat source is applied to the under side of said plastic lid, applying pressure to said lid to cause said lid to be pressed down onto a mat; compressing the tab against the top side of the lid which has been softened and weakened by the application of heat on its under side by said heating head thereby bonding said tab to said lid.

5. The process according to claim 1 wherein said pressure directly applied to said pull tab is about pounds per square inch and said heat applied to the bottom surface of said lid is about 25 0 F. 7

References Cited UNITED STATES. PATENTS DOUGLAS J. DRUMMOND, Primary Examiner

Claims (1)

1. A PROCESS FOR FORMING AN OPENING IN THE THERMOPLASTIC LID, COMPRISING THE STEPS OF BRINGING A PULL TAB ALSO CONSISTING OF A THERMOPLASTIC MATERIAL IN CONTACT WITH A PORTION OF THE PLASTIC LID ON THE TOP SURFACE THEREOF; APPLYING PRESSURE TO THE TOP SURFACE OF SAID PORTION OF THE LID; APPLYING HEAT TO THE BOTTOM SURFACE OF SAID PORTION OF THE LID, THEREBY CAUSING THE PULL TAB TO BE HEAT SEALED TO THE SAID PORTION OF THE LID AND ALSO CAUSING THE SAID PORTION OF THE LID TO BECOME SUFFICIENTLY STRUCTURALLY WEAKENED SO THAT WHEN THE PULL TAB IS REMOVED THIS PORTION OF THE LID WILL REMAIN ATTACHED TO THE PULL TAB AND THEREBY CAUSE AN OPENING TO BE MADE IN THE LID.
US617405A 1964-11-02 1967-02-20 Heat sealed pull tab Expired - Lifetime US3475246A (en)

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Application Number Priority Date Filing Date Title
US408281A US3321123A (en) 1964-11-02 1964-11-02 Heat sealed pull tab
US61740567A true 1967-02-20 1967-02-20

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378074A (en) * 1981-05-18 1983-03-29 Minnesota Mining And Manufacturing Company Easy open closure system
FR2841817A1 (en) * 2002-07-02 2004-01-09 Europlastiques Sa Food product container has tab moulded to base to facilitate removal from product when inverted
US8809744B2 (en) 2010-12-01 2014-08-19 Scentsy, Inc. Wax removers for scent warmers and related methods

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3032463A (en) * 1961-06-07 1962-05-01 Morgan Adhesives Co Method for making punched label stock
US3297508A (en) * 1962-12-10 1967-01-10 Meyercord Co Dry strip decalcomania or transfer and method of use

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3032463A (en) * 1961-06-07 1962-05-01 Morgan Adhesives Co Method for making punched label stock
US3297508A (en) * 1962-12-10 1967-01-10 Meyercord Co Dry strip decalcomania or transfer and method of use

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4378074A (en) * 1981-05-18 1983-03-29 Minnesota Mining And Manufacturing Company Easy open closure system
FR2841817A1 (en) * 2002-07-02 2004-01-09 Europlastiques Sa Food product container has tab moulded to base to facilitate removal from product when inverted
US8809744B2 (en) 2010-12-01 2014-08-19 Scentsy, Inc. Wax removers for scent warmers and related methods

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Owner name: SEALRIGHT CO., INC. A DE CORP.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:PHILLIPS PETROLEUM COMPANY A DE CORP.;REEL/FRAME:004099/0393

Effective date: 19821116