CA2314456A1 - Pressure sensitive adhesive tear tape - Google Patents
Pressure sensitive adhesive tear tape Download PDFInfo
- Publication number
- CA2314456A1 CA2314456A1 CA002314456A CA2314456A CA2314456A1 CA 2314456 A1 CA2314456 A1 CA 2314456A1 CA 002314456 A CA002314456 A CA 002314456A CA 2314456 A CA2314456 A CA 2314456A CA 2314456 A1 CA2314456 A1 CA 2314456A1
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- CA
- Canada
- Prior art keywords
- film
- tape
- pressure sensitive
- sensitive adhesive
- tear tape
- 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.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/20—Adhesives in the form of films or foils characterised by their carriers
- C09J7/22—Plastics; Metallised plastics
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2423/00—Presence of polyolefin
- C09J2423/006—Presence of polyolefin in the substrate
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2467/00—Presence of polyester
- C09J2467/006—Presence of polyester in the substrate
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Adhesive Tapes (AREA)
Abstract
A tear tape for attachment to an overwrap material is formed by longitudinally drawing a bi-axially oriented film of a polymeric material, preferably polyester so as to effect further orientation in the longitudinal direction. After drawing a layer of a pressure sensitive adhesive is applied on one surface a nd a release coat is applied to the other surface so as to provide a release acti on when contacting the pressure sensitive adhesive. The film is longitudinally slit with the adhesive layer thereon into a plurality of side by side tapes which are woun d into individual supply packages for supply to an end use machine. The additional drawing can be carried out at a draw ratio and at a temperature such that th e heat shrink characteristics of the tape are matched to the overwrap material for heat shrinking of the overwrap onto the underlying product without puckering. The extra longitudinal strength imparted by the drawing allows the formation of a thinner tape while matching the absolute strength value required to carry out the tearing action.
Description
PRESSURE SENSITIVE ADHESIVE TEAR TAPE
This invention relates to a method of forming a pressure sensitive adhesive tear tape of high tensile strength and low elongation and to a tape formed by the method.
BACKGROUND OF THE INVENTION
Pressure sensitive adhesive tapes with which the present invention is concerned are widely used as tear tapes, but in addition it may be possible to use tapes of the present invention as pressure sensitive strapping, as reinforcement for corrugated products and for similar purposes.
Tear tapes are widely used in packaging to tear a packaging material along a tear line defined by the tear tape. This is used in filmic packaging materials but also can be used with paper or board materials such as for soapboxes or courier envelopes. The tear' tape thus forms a very small part of the packaging material but provides a function, 'which is very important for customer satisfaction. It is of course desirable therefore to reduce the amount of material and cost involved in the tear tape construction.
Tear tapes conventionally comprise a strip of a suitable plastics material and generally polypropylene is chosen as this is relatively inexpensive and yet provides the required strength characteristics. The tear tape can have a width generally in the range 1.6 mm to 8.0 mm. The width is generally selected on the basis of minimum cost.
It is generally necessary to bond the tear tape to the packaging material in order to hold the tear tape in place during the manufacturing process and to locate the tear tape in place while it is tearing the packaging film to provide a clean straight tear line.
This invention relates to a method of forming a pressure sensitive adhesive tear tape of high tensile strength and low elongation and to a tape formed by the method.
BACKGROUND OF THE INVENTION
Pressure sensitive adhesive tapes with which the present invention is concerned are widely used as tear tapes, but in addition it may be possible to use tapes of the present invention as pressure sensitive strapping, as reinforcement for corrugated products and for similar purposes.
Tear tapes are widely used in packaging to tear a packaging material along a tear line defined by the tear tape. This is used in filmic packaging materials but also can be used with paper or board materials such as for soapboxes or courier envelopes. The tear' tape thus forms a very small part of the packaging material but provides a function, 'which is very important for customer satisfaction. It is of course desirable therefore to reduce the amount of material and cost involved in the tear tape construction.
Tear tapes conventionally comprise a strip of a suitable plastics material and generally polypropylene is chosen as this is relatively inexpensive and yet provides the required strength characteristics. The tear tape can have a width generally in the range 1.6 mm to 8.0 mm. The width is generally selected on the basis of minimum cost.
It is generally necessary to bond the tear tape to the packaging material in order to hold the tear tape in place during the manufacturing process and to locate the tear tape in place while it is tearing the packaging film to provide a clean straight tear line.
2 Some packaging processes include the application of wax type adhesive to the tear tape on the packaging line so that an adhesive applicator is provided as part of the machine and applies the adhesive to the packaging film immediately prior to the tear tape application.
Tear tapes are also supplied in package form carrying a pressure sensitive adhesive on one surface. Such tapes are formed by slitting from a web of the tape material on which is already applied the pressure sensitive adhesive.
A tape of this type is shown in U.S. Patent 4,844,962 (May et al assigned to Payne Packaging Limited). This patent discloses a mono-axially oriented tape material, which up to now has provided the maximum strength at minimum thickness.
In prior U.S. Patent 4,887,714 (O'Connor assigned to,KT Industries Inc.) is shown a modified form of tear tape in which the pressure sensitive adhesive is applied as a narrower line to the tear tape strip after the tear tape has been slit from a web of the film. This process has been commercially successful and operates satisfactorily on the packaging machine. The tape manufactured in accordance with this patent has been formed from bi-axially oriented polyester, which has many desirable properties but cannot provide the required longitudinal strength when supplied in narrower widths of the order of 2 mm.
An extruded pressure sensitive adhesive material is disclosed in U.S.
Patent 5,520,868 (O'Connor) in which a base polymer film is extruded in tape width and subsequently drawn with an adhesive material on one side to reduce the thickness of both tree tape and the adhesive. This method has not achieved commercial success.
Generally, tear tapes are manufactured by extruding a web of polypropylene, polyester or other suitable material, which is then drawn in machine direction to effect orientation of the extruded layer. The amount of draw possible is
Tear tapes are also supplied in package form carrying a pressure sensitive adhesive on one surface. Such tapes are formed by slitting from a web of the tape material on which is already applied the pressure sensitive adhesive.
A tape of this type is shown in U.S. Patent 4,844,962 (May et al assigned to Payne Packaging Limited). This patent discloses a mono-axially oriented tape material, which up to now has provided the maximum strength at minimum thickness.
In prior U.S. Patent 4,887,714 (O'Connor assigned to,KT Industries Inc.) is shown a modified form of tear tape in which the pressure sensitive adhesive is applied as a narrower line to the tear tape strip after the tear tape has been slit from a web of the film. This process has been commercially successful and operates satisfactorily on the packaging machine. The tape manufactured in accordance with this patent has been formed from bi-axially oriented polyester, which has many desirable properties but cannot provide the required longitudinal strength when supplied in narrower widths of the order of 2 mm.
An extruded pressure sensitive adhesive material is disclosed in U.S.
Patent 5,520,868 (O'Connor) in which a base polymer film is extruded in tape width and subsequently drawn with an adhesive material on one side to reduce the thickness of both tree tape and the adhesive. This method has not achieved commercial success.
Generally, tear tapes are manufactured by extruding a web of polypropylene, polyester or other suitable material, which is then drawn in machine direction to effect orientation of the extruded layer. The amount of draw possible is
3 limited by the tendency of the material to fibrillate beyond a predetermined extension. After the longitudinal draw is effected, the web is drawn in the transverse direction by a tentering frame which increases the total orientation up to a level to give the required mechanical properties of strength and resistance to elongation.
This material is known as biaxially oriented. This web is then slit into a plurality of longitudinally continuous side-by side tapes which can be coated with adhesive in a process subsequent to the slitting as in the O'Connor patent set out above or can be coated in web width with the adhesive prior to slitting as in the May patent above.
However, the mechanical limitations of the orientation process limit the amount of orientation, which can be effected so that the resultant product is of reduced strength and increased thickness relative to the theoretical optimum. .
U.S. Patent 5,118,566 (Wilhelm) issued June 2, 1992 discloses that biaxially oriented film can be further oriented in the longitudinal direction.
However the process is stated to be disadvantageous with a number of problems in that the finished product has a marked longitudinal shrinkage.
Up till now, therefore, pressure sensitive adhesive tear tapes for use in adhesive attachment to an overwrap material have been manufactured either from mono axially oriented polypropylene, polyester or from biaxially oriented polyester.
These materials have displayed the necessary characteristics of strength and low elongation and have been accepted in the marketplace.
SUMMARY OF THE INVENTION
It is one object of the present invention, therefore, to provide a method of manufacturing a tear tape which has improved strength characteristics allowing the tape to be of reduced thickness and width.
According to one aspect of the invention there is provided a method for forming a tear tape comprising:
This material is known as biaxially oriented. This web is then slit into a plurality of longitudinally continuous side-by side tapes which can be coated with adhesive in a process subsequent to the slitting as in the O'Connor patent set out above or can be coated in web width with the adhesive prior to slitting as in the May patent above.
However, the mechanical limitations of the orientation process limit the amount of orientation, which can be effected so that the resultant product is of reduced strength and increased thickness relative to the theoretical optimum. .
U.S. Patent 5,118,566 (Wilhelm) issued June 2, 1992 discloses that biaxially oriented film can be further oriented in the longitudinal direction.
However the process is stated to be disadvantageous with a number of problems in that the finished product has a marked longitudinal shrinkage.
Up till now, therefore, pressure sensitive adhesive tear tapes for use in adhesive attachment to an overwrap material have been manufactured either from mono axially oriented polypropylene, polyester or from biaxially oriented polyester.
These materials have displayed the necessary characteristics of strength and low elongation and have been accepted in the marketplace.
SUMMARY OF THE INVENTION
It is one object of the present invention, therefore, to provide a method of manufacturing a tear tape which has improved strength characteristics allowing the tape to be of reduced thickness and width.
According to one aspect of the invention there is provided a method for forming a tear tape comprising:
4 providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages for supply to an end use machine.
The film may be formed of polyester, polypropylene, nylon or polyethylene.
Preferably the film is drawn to a thickness less than 35 microns which may be less than 20 microns and even down to 12.7 microns.
Preferably the tape has a width less than 5 mm, which may be less than 2 mm, a break strength of greater than 1.5 Ibs and an elongation to break in the range 15 to 60 % and more preferably in the range 30% to 50%.
According to a second aspect of the invention there is provided a method for wrapping an article with a tearable film comprising:
forming a tear tape by:
providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages for supply to an end use machine.
The film may be formed of polyester, polypropylene, nylon or polyethylene.
Preferably the film is drawn to a thickness less than 35 microns which may be less than 20 microns and even down to 12.7 microns.
Preferably the tape has a width less than 5 mm, which may be less than 2 mm, a break strength of greater than 1.5 Ibs and an elongation to break in the range 15 to 60 % and more preferably in the range 30% to 50%.
According to a second aspect of the invention there is provided a method for wrapping an article with a tearable film comprising:
forming a tear tape by:
providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
5 longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages;
supplying the wrapping material;
applying the tear tape to the wrapping material such that it is attached thereto by the adhesive;
wrapping the wrapping material around the article and heat shrinking the wrapping material to engage tightly around the article;
and selecting a draw ratio for the drawing of the film such that the elongation of the tape so formed is matched to the wrapping material such that the heat shrinking is effected without puckering of the tear tape.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:
Figure 1 is a schematic illustration of a method for manufacturing a :?0 tear tape according to the present invention.
Figure 2 is an isometric view of a package including an overwrap material and a tear tape attached thereto.
Figure :3 is a cross-sectional view of two overlapping portions of the overwrap material at a seam where the tear tape passes through the seam.
:?5 In the drawings like characters of reference indicate corresponding parts in the different figures.
and winding the tapes into individual supply packages;
supplying the wrapping material;
applying the tear tape to the wrapping material such that it is attached thereto by the adhesive;
wrapping the wrapping material around the article and heat shrinking the wrapping material to engage tightly around the article;
and selecting a draw ratio for the drawing of the film such that the elongation of the tape so formed is matched to the wrapping material such that the heat shrinking is effected without puckering of the tear tape.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:
Figure 1 is a schematic illustration of a method for manufacturing a :?0 tear tape according to the present invention.
Figure 2 is an isometric view of a package including an overwrap material and a tear tape attached thereto.
Figure :3 is a cross-sectional view of two overlapping portions of the overwrap material at a seam where the tear tape passes through the seam.
:?5 In the drawings like characters of reference indicate corresponding parts in the different figures.
6 DETAILED DESCRIPTI N
In Figure 1 is shown a supply 10 of a web 11 of a bi-axially oriented film of a suitable polymer material. Preferably material is polyester but other materials such as polypropylene, polyethylene and nylon can also be used in some cases. The preferred material is polyester.
The film when supplied has a thickness in the range 0.00048" to 0.0020". The elongation of the film in the longitudinal direction will range from 80 to 120 % and 60 to 90°/~ in the transverse direction.
The film when supplied is biaxially oriented that is it has been initially oriented in a longitudinal direction and subsequently oriented in the transverse direction to provide orientation in both directions as opposed to the single longitudinal direction of monoaxially oriented materials. The tensile strength of the film in the longitudinal direction will range from 20,000 to 30,000 psi and 30,000 to 35,000 psi in the transverse direction.
Commercial material is available from a number of suppliers including for example DUPONT and Mitsubishi.
In the <~rrangement shown in Figure 1, the film in its initial biaxially oriented state is passed through a feed roll system 12 for controlling a feed speed of the sheet and is fed therefrom to a delivery roll system which carries the sheet forwardly from the feed rollers to a wind up section 14. The feed section 12 and the delivery section 13 are operated at predetermined speed ratio controlled by a drive control system 15 of a conventional nature. Thus a predetermined level of draw can be provided between the rollers 12 and 13 so as to increase the speed of the film as it is drawn away frorn a drawing section 16 between the two sets of rollers.
In a :?5 heating section the aheet material can be heated by a heater 17 such that the material is heated to a temperature to allow drawing to be effected. The pre-drawing
In Figure 1 is shown a supply 10 of a web 11 of a bi-axially oriented film of a suitable polymer material. Preferably material is polyester but other materials such as polypropylene, polyethylene and nylon can also be used in some cases. The preferred material is polyester.
The film when supplied has a thickness in the range 0.00048" to 0.0020". The elongation of the film in the longitudinal direction will range from 80 to 120 % and 60 to 90°/~ in the transverse direction.
The film when supplied is biaxially oriented that is it has been initially oriented in a longitudinal direction and subsequently oriented in the transverse direction to provide orientation in both directions as opposed to the single longitudinal direction of monoaxially oriented materials. The tensile strength of the film in the longitudinal direction will range from 20,000 to 30,000 psi and 30,000 to 35,000 psi in the transverse direction.
Commercial material is available from a number of suppliers including for example DUPONT and Mitsubishi.
In the <~rrangement shown in Figure 1, the film in its initial biaxially oriented state is passed through a feed roll system 12 for controlling a feed speed of the sheet and is fed therefrom to a delivery roll system which carries the sheet forwardly from the feed rollers to a wind up section 14. The feed section 12 and the delivery section 13 are operated at predetermined speed ratio controlled by a drive control system 15 of a conventional nature. Thus a predetermined level of draw can be provided between the rollers 12 and 13 so as to increase the speed of the film as it is drawn away frorn a drawing section 16 between the two sets of rollers.
In a :?5 heating section the aheet material can be heated by a heater 17 such that the material is heated to a temperature to allow drawing to be effected. The pre-drawing
7 rollers, drawing rollers and annealing roller are heated to a temperature to allow drawing to be effected.
The sheet is maintained in web width by the rollers 12 and 13 and is rolled in web width at the winding section 14.
The roll from the winding section 14 is passed to a feed supply 14A for feeding a second section of the process in which the drawn film is coated on its underside by a coating system 18 applying a release coat material of conventional nature. On the upper surface of the film is applied initially an optional printing step 19 which applies band of printed information or simple printed colored lines along the length of the sheet. Downstream, or in some cases upstream of the printing section is a coating section 20 which applies a conventional pressure sensitive adhesive material over the full area of the sheet. .The materials are dried and set so that the sheet carrying the applied materials is wound into a section 21 to form a further supply roll 21A. In a third section of the method, the sheet material from the supply roll 28A is passed through a slitting station 22 and is wound into individual tapes at a series of take up winding sections 23A, 23B and 23C to form individual packages of the slit tape.
Thus when formed each tape is defined by a base film material 30 and a covering adhesive layer 31 which extends to edges of the tape as indicated in Figure 3. An optional printing layer 32 is applied on the upper surface of the tape with the adhesive layer 31. An opposite release coating 33 is carried on the tape to prevent bonding of the reverse side of the tape to the adhesive layer during the packaging process.
As sho~nrn in Figures 2 and 3 the tear tape defined by the base film 30 and the adhesive layer 31 is attached to an overwrap material 40 so that it is carried thereby. The overwrap material is wrapped around a packaged article 41 such as a
The sheet is maintained in web width by the rollers 12 and 13 and is rolled in web width at the winding section 14.
The roll from the winding section 14 is passed to a feed supply 14A for feeding a second section of the process in which the drawn film is coated on its underside by a coating system 18 applying a release coat material of conventional nature. On the upper surface of the film is applied initially an optional printing step 19 which applies band of printed information or simple printed colored lines along the length of the sheet. Downstream, or in some cases upstream of the printing section is a coating section 20 which applies a conventional pressure sensitive adhesive material over the full area of the sheet. .The materials are dried and set so that the sheet carrying the applied materials is wound into a section 21 to form a further supply roll 21A. In a third section of the method, the sheet material from the supply roll 28A is passed through a slitting station 22 and is wound into individual tapes at a series of take up winding sections 23A, 23B and 23C to form individual packages of the slit tape.
Thus when formed each tape is defined by a base film material 30 and a covering adhesive layer 31 which extends to edges of the tape as indicated in Figure 3. An optional printing layer 32 is applied on the upper surface of the tape with the adhesive layer 31. An opposite release coating 33 is carried on the tape to prevent bonding of the reverse side of the tape to the adhesive layer during the packaging process.
As sho~nrn in Figures 2 and 3 the tear tape defined by the base film 30 and the adhesive layer 31 is attached to an overwrap material 40 so that it is carried thereby. The overwrap material is wrapped around a packaged article 41 such as a
8 pack of cigarettes or the like. The overwrap material is overlapped at a seam 42 and the tear tape passes through the seam from underneath the overwrap material so that a tab 43 of the tear tape is exposed at the seam for pulling of the tear tape to effect tearing of the averwrap material 40.
As shown in Figure 3, at the seam 42 on either side of the tear tape there is a narrow arE;a 44 defined by the finite thickness of the tear tape which can allow penetration of air and escape of moisture thus allowing the contents to be increased or decreased in moisture content with the possibility of spoilage of the contents after a period of storage.
According to the present invention, the additional drawing step of the biaxially oriented material allows the film to be reduced in thickness from a conventional thickness of the order of 45 microns down to a thickness which is less than 35 microns and more preferably less than 20 microns. It is the intention to minimize the thickness of the finished tape while providing sufficient longitudinal strength. This allowable thickness reduction in the finished tape is obtained due to the fact that the longitudinal strength is relatively significantly increased by the additional drawing of the film.
Of course, in order to provide a predetermined strength which is necessary for the tearing action, a predetermined longitudinal strength is required :20 which is of the order of 40,000 Ibs per square inch (which equates to an absolute value of 1.5 Ib. for a tape of the order of 0.0787 inches in width and 0.00048 inches in thickness). Thus the strength of the tape should be greater than 1.5 Ibs.
In order to achieve this in conventional tear tapes, a thickness greater than 35 microns is normally required since thinner material does not have the :?5 sufficient strength characteristics. However the increase in strength provided by the
As shown in Figure 3, at the seam 42 on either side of the tear tape there is a narrow arE;a 44 defined by the finite thickness of the tear tape which can allow penetration of air and escape of moisture thus allowing the contents to be increased or decreased in moisture content with the possibility of spoilage of the contents after a period of storage.
According to the present invention, the additional drawing step of the biaxially oriented material allows the film to be reduced in thickness from a conventional thickness of the order of 45 microns down to a thickness which is less than 35 microns and more preferably less than 20 microns. It is the intention to minimize the thickness of the finished tape while providing sufficient longitudinal strength. This allowable thickness reduction in the finished tape is obtained due to the fact that the longitudinal strength is relatively significantly increased by the additional drawing of the film.
Of course, in order to provide a predetermined strength which is necessary for the tearing action, a predetermined longitudinal strength is required :20 which is of the order of 40,000 Ibs per square inch (which equates to an absolute value of 1.5 Ib. for a tape of the order of 0.0787 inches in width and 0.00048 inches in thickness). Thus the strength of the tape should be greater than 1.5 Ibs.
In order to achieve this in conventional tear tapes, a thickness greater than 35 microns is normally required since thinner material does not have the :?5 sufficient strength characteristics. However the increase in strength provided by the
9 present invention allows a significant reduction of the thickness of the material and thus significantly reduces the dimensions of the air penetration zones 44.
Yet further, significant reduction in the thickness of the film acts to allow formation of a package of significantly increased length of material since the package can only t>e formed up to a predetermined diameter and therefore a reduction in thickness generates an increase in length within the predetermined volume of the finished package. This increase in length on a supply package has significant ergonomic improvements allowing reduced operator down time.
Yet further it has been found that the slit edges of a tape formed in this manner are improved relative to those generated from mono axial oriented materials since the transverse orientation allows an enhanced slitting action thus avoiding the generation of slitting problems and the generation of stray fibers or fibrillation at the slit edges.
In a particularly preferred process, the overwrap material when applied to the package 41 is of a character which allows a heat shrink action to occur so that the overlap material is pulled down tight onto the outside surface of the package thus avoiding bubbles and wrinkles which detract from the appearance of a the graphics on the printed outside surface of the package itself. Yet further, the longitudinal extension of the tear tape can be controlled by modifying the draw ratio :?0 controlled by the drive system 15 and the draw temperature so that the elongation is tailored to the particular heat shrink characteristics of the overwrap material. In this way puckering of the tear tape during the heat shrink process is avoided since the characteristics of the tear tape are directly tailored to the characteristics of the overwrap material.
?5 It has been determined that the amount of elongation or extension in the tear tape can effect the puckering of the overwrap film when the tear tape is applied. If the tear tape has a low elongation in the range of 15 to 30 % the puckering of the tear tape is noticeable. If the tear tape has an elongation in the range of 30 to 60 % the puckering appears to be more controlled when the tear tape is applied to the overwrap film. The heat that is applied to the overwrap film causes 5 the film to shrink or lose elongation in the longitudinal and transverse directions.
The tear tape, because of the biaxial orientation and heat set properties, will remain more stable with less puckering to the overwrap film when applied compared to a monoaxial film. The draw ratios to the film that imparts elongation characteristics from a range of 15 to 60 % are from a range of 1.3/1.0 to 1.8/1Ø
Yet further, significant reduction in the thickness of the film acts to allow formation of a package of significantly increased length of material since the package can only t>e formed up to a predetermined diameter and therefore a reduction in thickness generates an increase in length within the predetermined volume of the finished package. This increase in length on a supply package has significant ergonomic improvements allowing reduced operator down time.
Yet further it has been found that the slit edges of a tape formed in this manner are improved relative to those generated from mono axial oriented materials since the transverse orientation allows an enhanced slitting action thus avoiding the generation of slitting problems and the generation of stray fibers or fibrillation at the slit edges.
In a particularly preferred process, the overwrap material when applied to the package 41 is of a character which allows a heat shrink action to occur so that the overlap material is pulled down tight onto the outside surface of the package thus avoiding bubbles and wrinkles which detract from the appearance of a the graphics on the printed outside surface of the package itself. Yet further, the longitudinal extension of the tear tape can be controlled by modifying the draw ratio :?0 controlled by the drive system 15 and the draw temperature so that the elongation is tailored to the particular heat shrink characteristics of the overwrap material. In this way puckering of the tear tape during the heat shrink process is avoided since the characteristics of the tear tape are directly tailored to the characteristics of the overwrap material.
?5 It has been determined that the amount of elongation or extension in the tear tape can effect the puckering of the overwrap film when the tear tape is applied. If the tear tape has a low elongation in the range of 15 to 30 % the puckering of the tear tape is noticeable. If the tear tape has an elongation in the range of 30 to 60 % the puckering appears to be more controlled when the tear tape is applied to the overwrap film. The heat that is applied to the overwrap film causes 5 the film to shrink or lose elongation in the longitudinal and transverse directions.
The tear tape, because of the biaxial orientation and heat set properties, will remain more stable with less puckering to the overwrap film when applied compared to a monoaxial film. The draw ratios to the film that imparts elongation characteristics from a range of 15 to 60 % are from a range of 1.3/1.0 to 1.8/1Ø
10 Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.
Claims (20)
1. A method for forming a tear tape comprising:
providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages for supply to an end use machine.
providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages for supply to an end use machine.
2. The method according to Claim 1 wherein the film is formed of polyester.
3. The method according to Claim 1 wherein the film is formed of polypropylene.
4. The method according to Claim 1 wherein the film is formed of nylon.
5. The method according to Claim 1 wherein the film is formed of polyethylene.
6. The method according to Claim 1 wherein the film is drawn to a thickness less than 35 microns.
7. The method according to Claim 1 wherein the film is drawn to a thickness less than 20 microns.
8. The method according to Claim 1 wherein the tape has a width less than 5 mm.
9. The method according to Claim 1 wherein the tape has a width less than 2 mm.
10. The method according to Claim 1 wherein the tape has a break strength of greater than 1.5 lb.
11. The method according to Claim 1 wherein the tape has an elongation to break ins the range 15 to 60% and more preferably 30% to 50%.
12. A method for wrapping an article with a tearable film comprising:
forming a tear tape by:
providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages;
supplying the wrapping material;
applying the tear tape to the wrapping material such that it is attached thereto by the adhesive;
wrapping the wrapping material around the article and heat shrinking the wrapping material to engage tightly around the article;
and selecting a draw ratio for the drawing of the film such that the elongation of the tape so formed is matched to the wrapping material such that the heat shrinking is effected without puckering of the tear tape.
forming a tear tape by:
providing a bi-axially oriented film of a polymeric material having first and second surfaces;
longitudinally drawing the film so as to effect further orientation in the longitudinal direction;
applying a layer of a pressure sensitive adhesive covering the first surface of the drawn film;
arranging the second surface so as to provide a release action when contacting the pressure sensitive adhesive;
longitudinally slitting the film and the adhesive layer thereon into a plurality of side by side tapes;
and winding the tapes into individual supply packages;
supplying the wrapping material;
applying the tear tape to the wrapping material such that it is attached thereto by the adhesive;
wrapping the wrapping material around the article and heat shrinking the wrapping material to engage tightly around the article;
and selecting a draw ratio for the drawing of the film such that the elongation of the tape so formed is matched to the wrapping material such that the heat shrinking is effected without puckering of the tear tape.
13. The method according to Claim 12 wherein the film is formed of polyester.
14. The method according to Claim 12 wherein the film is formed of polypropylene.
15. The method according to Claim 12 wherein the film is formed of nylon.
16. The method according to Claim 12 wherein the film is formed of polyethylene.
17. The method according to Claim 12 wherein the film is drawn to a thickness less than 35 microns.
18. The method according to Claim 12 wherein the film is drawn to a thickness less than 20 microns.
19. The method according to Claim 12 wherein the tape has a width less than 5mm, a break strength of greater than 40000 psi and an elongation to break in the range 30% to 50%.
20. The method according to Claim 19 wherein the tape has a width less than 2mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002314456A CA2314456A1 (en) | 2000-07-21 | 2000-07-21 | Pressure sensitive adhesive tear tape |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002314456A CA2314456A1 (en) | 2000-07-21 | 2000-07-21 | Pressure sensitive adhesive tear tape |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2314456A1 true CA2314456A1 (en) | 2002-01-21 |
Family
ID=4166769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002314456A Abandoned CA2314456A1 (en) | 2000-07-21 | 2000-07-21 | Pressure sensitive adhesive tear tape |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2314456A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1754587A1 (en) | 2005-08-19 | 2007-02-21 | Wipak Walsrode GmbH & Co. KG | Tear strip for packagings |
-
2000
- 2000-07-21 CA CA002314456A patent/CA2314456A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1754587A1 (en) | 2005-08-19 | 2007-02-21 | Wipak Walsrode GmbH & Co. KG | Tear strip for packagings |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |