CA1092067A - Heat shrink packaging - Google Patents
Heat shrink packagingInfo
- Publication number
- CA1092067A CA1092067A CA216,344A CA216344A CA1092067A CA 1092067 A CA1092067 A CA 1092067A CA 216344 A CA216344 A CA 216344A CA 1092067 A CA1092067 A CA 1092067A
- Authority
- CA
- Canada
- Prior art keywords
- load
- film
- laminate
- packaged
- barrier film
- Prior art date
- 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
Links
Landscapes
- Packages (AREA)
- Laminated Bodies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method of utilizing a shrink wrap film to shrink wrap or bundle a load of articles or packages having a surface portion formed of the same material as the shrink wrap film. The load is assembled and wrapped with a laminate comprising an outer ply formed of the shrink wrap film and an inner barrier film formed of a material which will not fuse to any part of the load or said portions when subjected to film-shrinking heat. The wrapped load is thereafter heated to shrink the laminate about the load. Also disclosed is the resultant package, as well as several different laminates which may be used.
A method of utilizing a shrink wrap film to shrink wrap or bundle a load of articles or packages having a surface portion formed of the same material as the shrink wrap film. The load is assembled and wrapped with a laminate comprising an outer ply formed of the shrink wrap film and an inner barrier film formed of a material which will not fuse to any part of the load or said portions when subjected to film-shrinking heat. The wrapped load is thereafter heated to shrink the laminate about the load. Also disclosed is the resultant package, as well as several different laminates which may be used.
Description
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BACKGROUND AND SUMMAl~Y OF Tl~ INV~3NTION
There is a growing tendency to package many articles in ::
. .
plastic filn~ type enclosures rathcr than in cardboard cartons or the like, particularly when there is a shortage of paper products. For example, many canned and bottled food pFoducts are now being packaged by placing them on simple cardboard or plastic trays nd th~n passing : ' ' ' . '' , ' . .......
.
, .:, .
, 1 ; ';
, . . .. . - . . :..,:, ,: . .. . . ... : . -them through conventional heat shrink apparatus in which they are wrapped in a shrinkable film material, usually polyethylene, which is then heat shrunk in place. This packaging technique is used in cases in which it has been conventional in the past.
to use cardboard cartons. These individual packages, which may consist of twelve or twenty-four cans or bottles of a product, are then loaded on pallets for shipment. Because they slide relatively easily with respect to one another they ..
must be anchored to the pallet by some suitable means, It is common to do this using shrink wrap palletizing techniques, wherein the pallet and load is enclosed at least in part by a sheet or sleeve or pre-formed enclosure formed of heat shrinkable film and then passed through a shrink tunnel where heat is applied and the film tightly shrunk about the load.
One of the most commonly used heat shrink materials for this purpose is polyethylene film, however it has been discovered that when such film is shrunk on loads of indi.vidual packages where the packages themselves are wrapped in polyethylene fiIm, the shrinking heat applied in the tunnel causes the outer polyethylene sleeve or bag to fuse to the individual packages on:the pallet, thus making it difficult i not impossible to remove the individual packages intact from the pallet when they reach their destination.
It is therefore a primary object of the present invention to provide a packaging system, including method, film and package, which permits utilization of relatively inexpensive and readily available polyethylene as the primary shrink wrap material and which obviates the aforementioned .
disadvantage of known techni~es~. A related object : 2 bm:
. : . - ,:, - ' : ' ~.,' :.' , , ' ' ,: . . . : . .
1~)9Z06'7 .
resides in the provision of an improved shrink wrap material having greater toughness and strength than the commonly used polyethylene film.
In one particular aspect the present invention provides .
a method of utilizing a shrink wrap film to shrink wrap or :
bundle a load of one or more articles where an exposed surface thereon is formed of the same material as is said film, comprising the steps of assembling the load to be wrapped, wrapping at least a portion of the load with a laminate comprising an outer ply formed of said material and an inner barrier ~ply formed of a material which will not fuse to said exposed surfaces on said load when subjected to a film-shrinking heat, and heating the laminate to shrink same around the load.
In another particular aspect the present invention provides a packaged load including two layers of heat shrunk fllm : surrounding said load at least in part and having contiguous portions in relatively intimate engagement, one of said layers being a substantially continuous laminate of a heat shrinkable film of a given material and a barrier film, the other of said layers being a heat shrinkabls film of the same general composition as said given material, said laminate being positioned with said barrier film on the side of said laminate facing the other of said layers, said barrier film being formed from a heat shrinkable material which will not fuse to said given material when in contact therewith and subjected to film shrinking temperatures These and other objects of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevational view of a heat shrinkable . . . : :
, . .
. . : .
., . ,. : . :
,: . .: . . ... . , .: . .
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~ ~9;~1)67 film embodying the principles of the present invention and utilized in the form of a tube or sleeve, shown open;
Figure 2 is a side elevational view of a heat shrinkable film embodying the principles of the present invention and utilized in the form of a center-fold bag, shown in collapsed state;
Figure 3 is a side elevational view of a heat shrinkable -film embodying the principles of the present invention and utilized in the form of a gusseted bag, shown in a collapsed state; ~ . ~
Figure 4 is a sectional view of the laminate construction v of the heat shrinkable film of the present invention; and Figure 5 is a perspective view of a pallet load which has been packaged according to the principles of the present invention.
DETAILED DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
' The benefits of the present invention are derived from the u~e of a laminate as the heat shrinkable film material.
.
~ This laminate, shown in cross-section in Figure 4, comprises a primary ply 12 which is preferably formed of conventionally ~ .
used heat shrinkable polyethylene ' ,' ' ` ~ :' ':.:' : ' ' :
: .
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. .. . ~. . : : .
, 109206~
film. Layer or ply 12 has laminated thereto a continuous barrier layer or ply 14 which is formed of a material which (a) is heat shrinkable to approximately the same extent as polyethylene under similar heating conditionj, ~b) will heat seal to itself, (c) will not heat seal or fuse to polyethylene when subjected to fllm-shrinking temperatures, (d~ is of a material similar in flexibility to polyethylene, and (e) can be laminated to polyethylene. One material which has been found to have these characteristics and provide the 10 ~ ! advantages of the invention, and which is relatively available and economical is polybutylene, a high molecular weight isotactic polymer. This material is a polyolefin and is synthesized from butene-l monomer It is the preferred material. Other materials which can have these characteristics are polypropylene, polyvinyl chloride, and Surlyn 1601 resin, the latter being an ionomer resin manufactured by E. I. DuPont de Nemours and Co. Polybutylene is preferred over polypropylene because it is much stronger and tougher and results in a completed wrap ~ of improved toughness and strength, and it is preferred over polyvinyl chloride and Surlyn 1601 because lt is less expensive.
The heat shrinkable laminate may be formed in accordance with known laminating techniques, using standard ~` procedures. For example, the barrier ply may be co-extruded with the primar~ polyethylene ply in either blown form or sheet form, it may be coated on the primary ply with a sheet extruder, or separate film plys may be laminated together using conventional adhesives or other known lamination techniques.
It is important tha-t the barrier ply be continuous and-~ully ~, . .
r~ 4_ bm:
, . . :` . , .: : , .
.:
~1~92~i7 coextensive with the primary ply, not only to provide increased strength but also to assure that there are no exposed portions of the primary ply which may fuse to the packages which may constitute the load. On the other hand, it is preferable to provide as thin a barrier layer as is possible to minimize the cost of the laminate, such as when polybutylene is used, In practice it has been found that a layer as thin as 1/3 of a mil of polybutylene can be coextruded with polyethylene, Because the barrier layer contributes to the strength and toughness of the heat shrunk laminate, less polyethylene may be used.for a given application than would otherwise be used in the absence of a tough barrier layer.
The laminate may be used in any conventional form to accomplish the shrink wrapping or bundling of one or more articles. For example, the laminate is shown in Figure 1 in the : ~ .
form of a tube or sleeve 10 which is adapted to be dropped over : :
a load and then shrunk in place. Alternatively, it can be in : :
the form of a conventional centerfold bag 16, such as shown in Fiyure 2, comprising a folded end 18, heat sealed side edges 22 .
~20 and an open bottom 20. Furthermore, if desired it can be ~:
utilized in the form of a conventional gusseted bag~ such as shown at 2~ in Figure 3, comprising a heat sealed end 26, integral side gussets 28 and an open bottom 30, Other forms ~ ..
will be apparent to those skilled in the art, such as in sheet :.
form for use in various types of known automatic shrink wrap equipment. . ~.
In Figure 5 there is illustrated a representative .~ :
load consisting of a plurality of rolls 3~ of polyethylene film material disposed for shipment on a pallet 32 and heat shrunk in place on the pallet by means of the.laminate of the presènt .'; '"' ~. ': . ::
, ' ' . ' ',' . ,',' ,. '.' ' "'. ,: ,': ':', ,' " . :"
l~9ZO~;;7 :
invention utilized in the form of a sleeve or tube. Conventional heat shrinking procedure~ are used in connection with the laminate of the present invention~ Because the inner barrier ply 14 will not fuse to polyethylene, the individual rolls 34 may be easily removed from the pallet after delivery without the entire shrink wrap being fused thereto, The same is true in the case of loads consisting of other types of packages having polyethylene on the outer surface thereof, Thus, there is disclosed in the above description and in the drawing several embodiments of the invention which fully and effectively accomplish the objects thereof, However, it will be apparent that other variations in the details of construction may b~ indulged in without departing from the sphere of the invention herein described, or the scope of the appended claims.
.
bm:
.
.
, '' , ~' ' . ~ : , .
.~ , .' , . ' , : ~
~ .
C ' . . .
BACKGROUND AND SUMMAl~Y OF Tl~ INV~3NTION
There is a growing tendency to package many articles in ::
. .
plastic filn~ type enclosures rathcr than in cardboard cartons or the like, particularly when there is a shortage of paper products. For example, many canned and bottled food pFoducts are now being packaged by placing them on simple cardboard or plastic trays nd th~n passing : ' ' ' . '' , ' . .......
.
, .:, .
, 1 ; ';
, . . .. . - . . :..,:, ,: . .. . . ... : . -them through conventional heat shrink apparatus in which they are wrapped in a shrinkable film material, usually polyethylene, which is then heat shrunk in place. This packaging technique is used in cases in which it has been conventional in the past.
to use cardboard cartons. These individual packages, which may consist of twelve or twenty-four cans or bottles of a product, are then loaded on pallets for shipment. Because they slide relatively easily with respect to one another they ..
must be anchored to the pallet by some suitable means, It is common to do this using shrink wrap palletizing techniques, wherein the pallet and load is enclosed at least in part by a sheet or sleeve or pre-formed enclosure formed of heat shrinkable film and then passed through a shrink tunnel where heat is applied and the film tightly shrunk about the load.
One of the most commonly used heat shrink materials for this purpose is polyethylene film, however it has been discovered that when such film is shrunk on loads of indi.vidual packages where the packages themselves are wrapped in polyethylene fiIm, the shrinking heat applied in the tunnel causes the outer polyethylene sleeve or bag to fuse to the individual packages on:the pallet, thus making it difficult i not impossible to remove the individual packages intact from the pallet when they reach their destination.
It is therefore a primary object of the present invention to provide a packaging system, including method, film and package, which permits utilization of relatively inexpensive and readily available polyethylene as the primary shrink wrap material and which obviates the aforementioned .
disadvantage of known techni~es~. A related object : 2 bm:
. : . - ,:, - ' : ' ~.,' :.' , , ' ' ,: . . . : . .
1~)9Z06'7 .
resides in the provision of an improved shrink wrap material having greater toughness and strength than the commonly used polyethylene film.
In one particular aspect the present invention provides .
a method of utilizing a shrink wrap film to shrink wrap or :
bundle a load of one or more articles where an exposed surface thereon is formed of the same material as is said film, comprising the steps of assembling the load to be wrapped, wrapping at least a portion of the load with a laminate comprising an outer ply formed of said material and an inner barrier ~ply formed of a material which will not fuse to said exposed surfaces on said load when subjected to a film-shrinking heat, and heating the laminate to shrink same around the load.
In another particular aspect the present invention provides a packaged load including two layers of heat shrunk fllm : surrounding said load at least in part and having contiguous portions in relatively intimate engagement, one of said layers being a substantially continuous laminate of a heat shrinkable film of a given material and a barrier film, the other of said layers being a heat shrinkabls film of the same general composition as said given material, said laminate being positioned with said barrier film on the side of said laminate facing the other of said layers, said barrier film being formed from a heat shrinkable material which will not fuse to said given material when in contact therewith and subjected to film shrinking temperatures These and other objects of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a side elevational view of a heat shrinkable . . . : :
, . .
. . : .
., . ,. : . :
,: . .: . . ... . , .: . .
' . ' ' ' . ': , ' '~ ~ ' ' : . , :
- , .
..
~ ~9;~1)67 film embodying the principles of the present invention and utilized in the form of a tube or sleeve, shown open;
Figure 2 is a side elevational view of a heat shrinkable film embodying the principles of the present invention and utilized in the form of a center-fold bag, shown in collapsed state;
Figure 3 is a side elevational view of a heat shrinkable -film embodying the principles of the present invention and utilized in the form of a gusseted bag, shown in a collapsed state; ~ . ~
Figure 4 is a sectional view of the laminate construction v of the heat shrinkable film of the present invention; and Figure 5 is a perspective view of a pallet load which has been packaged according to the principles of the present invention.
DETAILED DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
' The benefits of the present invention are derived from the u~e of a laminate as the heat shrinkable film material.
.
~ This laminate, shown in cross-section in Figure 4, comprises a primary ply 12 which is preferably formed of conventionally ~ .
used heat shrinkable polyethylene ' ,' ' ` ~ :' ':.:' : ' ' :
: .
`:. ' :
~ -;~ -3a- ~ :
. .. . ~. . : : .
, 109206~
film. Layer or ply 12 has laminated thereto a continuous barrier layer or ply 14 which is formed of a material which (a) is heat shrinkable to approximately the same extent as polyethylene under similar heating conditionj, ~b) will heat seal to itself, (c) will not heat seal or fuse to polyethylene when subjected to fllm-shrinking temperatures, (d~ is of a material similar in flexibility to polyethylene, and (e) can be laminated to polyethylene. One material which has been found to have these characteristics and provide the 10 ~ ! advantages of the invention, and which is relatively available and economical is polybutylene, a high molecular weight isotactic polymer. This material is a polyolefin and is synthesized from butene-l monomer It is the preferred material. Other materials which can have these characteristics are polypropylene, polyvinyl chloride, and Surlyn 1601 resin, the latter being an ionomer resin manufactured by E. I. DuPont de Nemours and Co. Polybutylene is preferred over polypropylene because it is much stronger and tougher and results in a completed wrap ~ of improved toughness and strength, and it is preferred over polyvinyl chloride and Surlyn 1601 because lt is less expensive.
The heat shrinkable laminate may be formed in accordance with known laminating techniques, using standard ~` procedures. For example, the barrier ply may be co-extruded with the primar~ polyethylene ply in either blown form or sheet form, it may be coated on the primary ply with a sheet extruder, or separate film plys may be laminated together using conventional adhesives or other known lamination techniques.
It is important tha-t the barrier ply be continuous and-~ully ~, . .
r~ 4_ bm:
, . . :` . , .: : , .
.:
~1~92~i7 coextensive with the primary ply, not only to provide increased strength but also to assure that there are no exposed portions of the primary ply which may fuse to the packages which may constitute the load. On the other hand, it is preferable to provide as thin a barrier layer as is possible to minimize the cost of the laminate, such as when polybutylene is used, In practice it has been found that a layer as thin as 1/3 of a mil of polybutylene can be coextruded with polyethylene, Because the barrier layer contributes to the strength and toughness of the heat shrunk laminate, less polyethylene may be used.for a given application than would otherwise be used in the absence of a tough barrier layer.
The laminate may be used in any conventional form to accomplish the shrink wrapping or bundling of one or more articles. For example, the laminate is shown in Figure 1 in the : ~ .
form of a tube or sleeve 10 which is adapted to be dropped over : :
a load and then shrunk in place. Alternatively, it can be in : :
the form of a conventional centerfold bag 16, such as shown in Fiyure 2, comprising a folded end 18, heat sealed side edges 22 .
~20 and an open bottom 20. Furthermore, if desired it can be ~:
utilized in the form of a conventional gusseted bag~ such as shown at 2~ in Figure 3, comprising a heat sealed end 26, integral side gussets 28 and an open bottom 30, Other forms ~ ..
will be apparent to those skilled in the art, such as in sheet :.
form for use in various types of known automatic shrink wrap equipment. . ~.
In Figure 5 there is illustrated a representative .~ :
load consisting of a plurality of rolls 3~ of polyethylene film material disposed for shipment on a pallet 32 and heat shrunk in place on the pallet by means of the.laminate of the presènt .'; '"' ~. ': . ::
, ' ' . ' ',' . ,',' ,. '.' ' "'. ,: ,': ':', ,' " . :"
l~9ZO~;;7 :
invention utilized in the form of a sleeve or tube. Conventional heat shrinking procedure~ are used in connection with the laminate of the present invention~ Because the inner barrier ply 14 will not fuse to polyethylene, the individual rolls 34 may be easily removed from the pallet after delivery without the entire shrink wrap being fused thereto, The same is true in the case of loads consisting of other types of packages having polyethylene on the outer surface thereof, Thus, there is disclosed in the above description and in the drawing several embodiments of the invention which fully and effectively accomplish the objects thereof, However, it will be apparent that other variations in the details of construction may b~ indulged in without departing from the sphere of the invention herein described, or the scope of the appended claims.
.
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.
.
, '' , ~' ' . ~ : , .
Claims (17)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of utilizing a shrink wrap film to shrink wrap or bundle a load of one or more articles where an exposed surface thereon is formed of the same material as is said film, comprising the steps of assembling the load to be wrapped, wrapping at least a portion of the load with a laminate comprising an outer ply formed of said material and an inner barrier ply formed of a material which will not fuse to said exposed surfaces on said load when subjected to a film-shrinking heat, and heating the laminate to shrink same around the load.
2. A method as claimed in Claim 1, wherein said load is assembled upon a pallet and wherein a portion of the pallet is also wrapped with said laminate, whereby the shrinking will secure said load to said pallet.
3. A method as claimed in Claim 1, wherein said outer ply is formed of polyethylene.
4. A method as claimed in Claim 1, 2 or 3 wherein said inner barrier ply is formed of a material selected from the group consisting of polybutylene, polypropylene, polyvinyl chloride and ionomer resins.
5. A method as claimed in Claim 1, wherein said outer ply is formed of polyethylene and said inner barrier ply is formed of polybutylene.
6. A packaged load including two layers of heat shrunk film surrounding said load at least in part and having contiguous portions in relatively intimate engagement, one of said layers being a substantially continuous laminate of a heat shrinkable film of a given material and a barrier film, the other of said layers being a heat shrinkable film of the same general composition as said given material, said laminate being positioned with said barrier film on the side of said laminate facing the other of said layers, said barrier film being formed from a heat shrinkable material which will not fuse to said given material when in contact therewith and subjected to film shrinking temperatures.
7. A packaged load as claimed in Claim 6, wherein said laminate is a coextruded laminate.
8. A packaged load as claimed in Claim 6, wherein said given material is polyethylene.
9. A packaged load as claimed in Claim 6, wherein said barrier film is polybutylene.
10. A packaged load as claimed in Claim 6, wherein said given material is polyethylene and said barrier film is poly-butylene.
11. A packaged load as claimed in Claim 6, wherein said barrier film has heat shrink characteristics similar to those of said given material.
12. A packaged load as claimed in Claim 6, wherein said barrier film is formed of a material which is similar in flexibility to that of said given material.
13. A packaged load as claimed in Claim 6, wherein said barrier film is formed of a material which will heat seal to itself.
14. A packaged load as claimed in Claim 6, wherein said load comprises a plurality of individual packages having articles packaged within polyethylene film.
15. A packaged load as claimed in Claim 6, wherein said barrier film is as thin as possible while being continuous and coextensive with said given material to which it is laminated.
16. A packaged load as claimed in Claim 6, wherein said barrier film is polypropylene.
17. A packaged load as claimed in Claim 6, wherein said barrier film is polyvinyl chloride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA216,344A CA1092067A (en) | 1974-12-18 | 1974-12-18 | Heat shrink packaging |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA216,344A CA1092067A (en) | 1974-12-18 | 1974-12-18 | Heat shrink packaging |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1092067A true CA1092067A (en) | 1980-12-23 |
Family
ID=4101894
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA216,344A Expired CA1092067A (en) | 1974-12-18 | 1974-12-18 | Heat shrink packaging |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1092067A (en) |
-
1974
- 1974-12-18 CA CA216,344A patent/CA1092067A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |