WO1999048761A1

WO1999048761A1 - Automated method of attaching a handle to a container

Info

Publication number: WO1999048761A1
Application number: PCT/US1999/006516
Authority: WO
Inventors: Crawford Lyons
Original assignee: Graham Packaging Company, L.P.
Priority date: 1998-03-26
Filing date: 1999-03-25
Publication date: 1999-09-30
Also published as: CA2323911A1

Abstract

A method of permanently attaching a separate plastic handle (14) to a blow-molded plastic container (10) using an adhesive acceptable to existing recycling technology. The container body (12) is filled and capped before the handle (14) is glued to the container body (12). Preferably, the container body (12) is hot-filled and capped in automated machinery, and the hot-filled and capped container body (12) is permitted to cool to a predetermined temperature before the handle (14) is adhesively secured to the sidewall (24) of the container (10) with a hot melt adhesive.

Description

AUTOMATED METHOD OF ATTACHING A HANDLE TO A CONTAINER

Field of the Invention

The present invention relates to a method of permanently attaching a separately manufactured handle to a blow molded plastic container, and more particularly, the present invention relates to a method of gluing a plastic handle with a hot melt adhesive to a plastic bottle in an automated process

Background of the Invention

In the packaging of liquids, especially juice, recyclable blow-molded plastic containers are commonly filled and capped in an automated "hot-fill" process in which containers are filled with a beverage at an elevated temperature, are sealed, and are then allowed to cool The containers use vacuum flex panels to provide sufficient flexure to compensate for pressure and volume changes resulting from cooling of the hot-filled and capped containers. For example, U.S Patent No. 5,392,937 issued to Prevot et al , and owned by the assignee of the present application, discloses the use of vacuum flex panels in a hot-fillable, blow-molded container

Some containers require the use of handles to afford a consumer an easier ability to lift the container and/or pour its contents, preferably with one hand Smaller sized containers, such as 64 ounces and below, generally do not need handles because a consumer can grasp the sides of the container and manipulate the container with one hand However, larger containers, such as gallon containers, may require some form of handle in order for a consumer to have greater control of the container while lifting or pouring its contents with one hand

U. S Patent No. 5,622,579, which issued to Tobias and which is assigned to the assignee of the present application, discloses methods of ultrasonically welding a separately manufactured handle to an unfilled and uncapped blow molded plastic container One disclosed method requires that the empty container be pressurized with a gas to rigidity the walls of the container during the application of ultrasonic energy Another disclosed method requires the insertion of a backstop into the container and the positioning of the backstop against the sidewall of the container to rigidify selected portions of the container sidewall during the application of ultrasonic energy .After the handle is attached to the container, the empty container is filled and capped Co-pending U S Patent Application No 08/694,388, filed on

August 7, 1996 and assigned to the assignee of the present application, discloses a container having a separately manufactured handle permanently bonded to the container sidewall

U S Patent Nos 4,257,525, 4,273,246, 4,280,859, 4,368,826, 4,372,454 and 4,629,598, all of which issued to Thompson, disclose the use of adhesives to secure one end of an integrally formed handle, or both ends of a separately formed handle, to a blow molded container For instance, see the disclosure at column 12, lines 36-40 of the '525 Thompson patent For reasons to be discussed, the containers disclosed in the Thompson patents are not intended to be, or are capable of being, hot-filled in an automated process

Plastic containers which are manufactured by high-speed automated equipment preferably should be completely recyclable utilizing conventional recycling equipment and techniques Thus, any adhesive used on the containers, such as to attach a handle, should be recyclable along with the container body and handle This effectively limits the types of adhesives which can be utilized on such containers

The hot-fill process presents another obstacle to the use of adhesives since heat of the hot-filled liquid can cause the recyclable type of adhesive to fail in securing the handle to the bottle The handle may become dislodged during shipping or use by the consumer, or more seriously, may become dislodged during automated hot-filling and capping processes resulting in spillage of liquid at an elevated temperature

Another manufacturing problem is that the sidewall of an empty container may not be sufficiently rigid to allow a recyclable adhesive to create a secure bond between the container and handle when the handle is placed in pressure contact against the container For instance, any buckling of the container sidewall during setting of the adhesive may weaken the bond created by the adhesive, or may result in an inadequate bond being formed.

Although various of the above referenced methods for permanently attaching a handle to a container may be satisfactory for their intended purposes, a need exists for a reliable automated method of permanently gluing a plastic handle to a blow-molded plastic container The method should be capable of use with hot-filling techniques, and the entire container including the adhesive should be recyclable In addition, the handle attachment formed by the method should be capable of accommodating forces exerted under normal consumer use for package sizes of at least one gallon, and the manufacture of the container bodies and separate handles, and the method of attachment thereof, should be cost effective

Objects of the Invention

With the foregoing in mind, a primary object of the present invention is to provide an improved method of permanently attaching a separate handle to a blow- molded container in a reliable automated manner

Another object of the present invention is to provide a method of attaching a handle to a container in an automated hot-fill process

A further object of the present invention is to provide a container which is cost effective, structurally sound, aesthetically acceptable to consumers, and completely recyclable using conventional recycling techniques and processes

Summary of the Invention

The present invention provides an automated method of permanently attaching a handle to a blow molded plastic container Before the handle is attached to the container, the empty container is fed to a filling machine, filled with a liquid, and capped The separately manufactured handle is permanently attached by means of an adhesive to the filled and capped container Preferably, the empty container is hot- filled, the filled and capped container is cooled before the handle is attached, and the adhesive is a hot melt type of adhesive Brief Description of the Drawings

The foregoing and other objects, features and advantages of the present invention should become apparent from the following description when taken in conjunction with the accompanying drawings, in which Fig 1 is an elevational view of a container produced by the method of the present invention,

Fig 2 is an elevational view of the container illustrated in Fig 1 rotated 90° clockwise about a central vertical axis through the container,

Fig 3 is a perspective view of a separately formed handle, and Fig 4 is a flow chart of the steps of the automated method of the present invention

Detailed Description of the Preferred Method

Before turning to the unique aspects of the method of the present invention, a discussion follows concerning an example of a container which can be produced from the method

FIGs 1 and 2 illustrate a container 10 which has a permanently attached handle and which is produced from the method according to the present invention

The container 10 can be used to package a variety of products, but is particularly useful in packaging liquids, such as juice beverages filled hot The container 10 can be manufactured in various sizes, but is especially suitable for large sizes, such as a gallon, which usually requires two hands to manipulate effectively

The container 10 has a body portion 12 and a handle 14 which are formed separate from one another The body portion 12 is preferably produced by conventional blow molding operations, and the handle 14 is preferably produced by conventional injection molding techniques Both the body portion 12 and the handle

14 are preferably made from the same plastic, such as PET, so that both may be recycled without requiring separation The body portion 12 has a base 20, a finish 22 and a sidewall 24 extending between the base and finish The sidewall 24 includes a dome 26 located adjacent to the finish 22 and a lower portion 28 adjacent the base 20 As illustrated, the dome 26 and lower portion 28 are separated by a peripheral rib 30 The container 10 is preferably manufactured so that it is suited for hot-filling, however, the container 10 is also useful in non-hot-fill applications If the container is used in hot-fill processes, either the lower portion 28, the dome 26, or both, can have any number or type of vacuum flex panels for accommodating the volumetric changes of the container contents after the container is hot-filled, sealed and cooled FIG 1 illustrates a container which has four vacuum flex panels 32 located entirely in the lower portion 28 of the container (two vacuum flex panels 32 are shown in FIG 1, and two are located on the opposite side of the container, which is a mirror image of FIG 1) The lower portion 28 also provides label mounting areas To this end, peripheral rib 30 acts as an upper label bumper and a lower peripheral rib 34 acts as a lower label bumper

The container body portion 12 has an inwardly set recess 36 for providing a space for the user's fingers between the body portion 12 and the handle 14 The recess 36 can also provide a vacuum flex panel as disclosed in co-pending U S Application No 08/694,348 filed August 7, 1996, the disclosure of which is incorporated herein by reference

An upper handle mounting surface 50 is formed in the body portion 12 directly above the recess 36, and a lower handle mounting surface 52 is formed in the body portion 12 directly beneath the recess 36 The upper and lower handle mounting surfaces, 50 and 52, are preferably formed planar and substantially vertical but could extend at an angle relative to the vertical Both are preferably formed to readily receive a predetermined amount of adhesive as will be discussed

As shown in FIG 3, the handle 14 is preferably a rigid strap-type handle, which, when attached to the body portion 12, spans across the recess 36 in spaced relation therewith While the shape of the handle 14 can vary, it should preferably have a grip portion 56 which can be grasped comfortably by the consumer The handle 14 also has upper and lower ear attachment tabs, 58 and 60, which extend from opposite ends of the grip portion 56 and which are adapted to receive a predetermined amount of adhesive as will be discussed The upper tab 58 engages and is glued to the upper handle mounting surface 50, and the lower tab 60 engages and is glued to the lower handle mounting surface 52

Turning to the method of the present invention, and referring to FIG 4, the empty container body portion 12 and the handle 14 are produced in separate processes Although a specific body portion and handle configuration is discussed in detail above, any cooperatively engagable container body and handle configuration could be utilized by the method of the present invention In addition, the container body portions 12 and handles 14 can be produced and then shipped to the filling, capping, and attachment location, or alternatively, one or both can be manufactured at the filling location site and automatically transferred to downstream machinery

The body portion 12 is fed into any type of automated filling machinery (not shown) which is known in the art and which is used for automatically filling containers Preferably, the filling machinery is adapted to fill containers with a juice at an elevated temperature, for instance, at a temperature between about 178°F and 185°F

Immediately after the container body portions 12 are filled, they are transferred to automated capping machinery (not shown) which applies caps 16 to the container finishes for sealing the beverage within the container bodies

Preferably, after the containers are hot-filled and capped, the filled and capped container bodies are cooled to a temperature between about 60°F and 100°F, either by allowing them to cool while in transit, or by applying cooling air The amount of cooling is dependant on the type of adhesive used to attach the handle and the specific temperature requirements of the adhesive Alternatively, the hot-filled and capped container bodies could be cooled in a cooling chamber (not shown) or the like to speed cooling of the filled and capped container bodies If the container bodies are not hot-filled, the cooling step can be eliminated After the filled and capped containers are within a desired temperature range, a predetermined amount of adhesive 18 is applied to the upper and lower handle attachment tabs, 58 and 60, or to the upper and lower mounting surfaces, 50 and 52, on the container body 12, or to both The container body 12 and handle 14 are then brought into direct contact such that the upper tab 58 engages the upper mounting surface 50 and the lower tab 60 engages the lower mounting surface 52 The container body 12 and handle 14 are maintained in this engaged condition for a predetermined period of time to allow the adhesive to set and permanently secure the handle to the container body The filled, capped and handle attached container is then ready to be packed and shipped

By way of example and not by way of limitation, the adhesive is preferably a hot melt adhesive which can be removed from the container body and handle using current recycling technology The specific hot melt adhesive selected will determine the extent of cooling required and the period of time necessary to maintain the container body and handle in an engaged position before the adhesive properly sets For example, one useable hot melt adhesive is H.B Fuller HM-1672 which requires the container body to be at a temperature no greater than about 100°F and which requires about 3 seconds to set Alternatively, other hot melt adhesives could be used such as H B Fuller HM- 1853, or National Starch Instant Lok 342928 requiring cooling of the container body to between about 50°F and 150°F and requiring setting times of between about 1 second to 3 seconds

The present invention provides several advantages One advantage of filling and capping the container body before attaching the handle is that the sidewall of the container body is relatively rigid when the handle is attached as compared to the condition of the container body when the handle is attached to the sidewall of an empty container The rigid sidewall permits the handle to be brought firmly into contact with the container sidewall and held firmly against the sidewall for the period of time required for the adhesive to set This ensures that a reliable bond is created between the handle and sidewall enabling the container to withstand the rigors of shipping and use Another advantage of the method is that it avoids handles becoming dislodged from containers containing hot liquid. In addition, the method yields improved operating efficiencies by reducing the complexity of integrated blow molding and filling systems.

While a preferred method of manufacture and container have been described in detail, various modifications, alterations, and changes may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1 An automated method of permanently attaching a separate handle (14) to a container (10), comprising the steps of feeding an empty blow molded plastic container (10) to a filling machine, filling said empty container (10) in said filling machine, capping said filled container (10), and thereafter attaching a separately manufactured plastic handle (14) to said filled and capped container (10)

2 The method according to claim 1 , wherein said feeding, filling, capping and attaching steps are accomplished in the stated sequence

3 The method according to claim 1 , wherein said attaching step utilizes an adhesive to secure said handle (14) to said container (10)

4 The method according to claim 3, wherein said container (10) is filled with a liquid and wherein said liquid is hot-filled into said container (10) at a temperature of at least about 178┬░F

5 The method according to claim 3, further comprising the step of cooling said hot-filled and capped container (10) before attaching said handle (14) during said attaching step

6 The method according to claim 5, wherein said hot-filled and capped container (10) is cooled to a temperature of about 90┬░F or lower before said handle (14) is attached

7 The method according to claim 3, wherein said adhesive is a hot melt adhesive 10

8 The method according to claim 2, wherein said container (10) has a sidewall (24) with an inwardly set recess (36); wherein said handle (14) has a grip portion (56) between opposite ends (58, 60); and wherein said opposite ends (58, 60) are permanently attached with an adhesive to said sidewall (24) so that said grip portion (56) spans said recess (36).

9. The method according to claim 8, wherein said handle (14) is of injection molded plastic

10 An automated method of permanently attaching a separate handle (14) to a container (10), comprising the steps of feeding an empty blow molded plastic container (10) to a filling machine, hot-filling said empty container (10) in said filling machine, capping said hot-filled container (10), permitting said hot-filled and capped container (10) to cool; and attaching a separately manufactured plastic handle (14) to said capped container (10) after said capped container (10) has cooled.

1 1 The method according to claim 10, wherein said feeding, filling, capping, cooling and attaching steps are accomplished in the stated sequence.

12 The method according to claim 11, wherein said container (10) has a sidewall (24) with an inwardly set recess (36); wherein said handle (14) has a grip portion (56) between opposite ends (58, 60), and wherein said opposite ends (58, 60) are permanently attached with a hot melt adhesive to said sidewall (24) at locations above and below said recess (36) so that said grip portion (56) spans said recess (36)

13 A method according to claim 12, wherein the temperature of said beverage at filling is at least about 178┬░F, and wherein the temperature of said capped container (10) is less than about 90┬░F before said handle (14) is attached 11

14. A method according to claim 13, further comprising the steps of blow molding plastic containers (10) and injection molding plastic handles (14).

15 A blow molded plastic container (10) having a permanently attached handle (14) manufactured by the method according to claim 1.

16 A container (10) having a handle (14) for use in lifting and pouring its contents, comprising: a blow-molded plastic container body (12) having a base (20) and a finish (22) interconnected by a sidewall (24), said sidewall (24) having an inwardly set recess (36), and an elongate separately-formed plastic strap handle (14) having a grip portion (56) between opposite ends (58, 60), said opposite ends (58, 60) being permanently glued with a hot melt adhesive to said sidewall (24) so that said grip portion (56) spans said recess (36)