CA1199769A - System and process for orienting a multi-layer film structure - Google Patents
System and process for orienting a multi-layer film structureInfo
- Publication number
- CA1199769A CA1199769A CA000442337A CA442337A CA1199769A CA 1199769 A CA1199769 A CA 1199769A CA 000442337 A CA000442337 A CA 000442337A CA 442337 A CA442337 A CA 442337A CA 1199769 A CA1199769 A CA 1199769A
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- layer
- temperature
- comparatively
- orienting
- comparatively low
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/023—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B38/00—Ancillary operations in connection with laminating processes
- B32B38/0036—Heat treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/02—Physical, chemical or physicochemical properties
- B32B7/027—Thermal properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
- B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
- B29C35/12—Dielectric heating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/50—Properties of the layers or laminate having particular mechanical properties
- B32B2307/514—Oriented
- B32B2307/516—Oriented mono-axially
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/50—Properties of the layers or laminate having particular mechanical properties
- B32B2307/514—Oriented
- B32B2307/518—Oriented bi-axially
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2310/00—Treatment by energy or chemical effects
- B32B2310/12—Treatment by energy or chemical effects using dielectric properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/03—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers with respect to the orientation of features
Abstract
SYSTEM AND PROCESS FOR ORIENTING A MULTI-LAYER
FILM STRUCTURE
ABSTRACT
A method and system for orienting a multilayer polymeric film structure involve differential heating of the different film layers thereof by dielectric heating and then orienting the film layers at their respective optimal orientation temperatures.
FILM STRUCTURE
ABSTRACT
A method and system for orienting a multilayer polymeric film structure involve differential heating of the different film layers thereof by dielectric heating and then orienting the film layers at their respective optimal orientation temperatures.
Description
7l6~
~-2064 -1-SYSTEM A D PROCESS FOR ORIENTING A MULTI-LAYER
FILM STRUCTURE
The present invention relates to a system and process for orienting a multi-layer film structure.
The uniaxial and biaxial orientation of polymer films is a common commercial operation. Such orientation improves the physical properties of the films such as, flexibility, Elmendorf tear strength, elongation, tensile-strength, Mullen burst strength, impact strength and cold strength propertiesO The desired orientation is accomplished by subjecting the polymer film to longitudinal and/or transverse tensile stress at a temperature somewhat above the second order transition temperature or the glass transition temperature thereof. A
problem is however encountered when orienting a multi-layer film laminate of different polymeric films, ~or example, a film composed of a polyethylene layer bonded by an adhesive to a polyvinylidene chloride film which in turn is adhesively bonded to a second polyethylene film. The core layer, i.e. the polyvinylidene chloride film, has a higher softening point than the polyethylene film and, thus, the structure must be heated above the ideal or optimum orientation temperature for the polyethylene film. On orientation this will result in either a hazy film with less than optimum physical properties or a film with little or no orientation or, in the worst casq, a non-processible film, which is to say, a film so hot that it splits during orientation, resulting in no film at all. It is, therefore, an object o~ the present invention to minimize or alleviate this problem.
Accordingly, the invention resides in one aspect in a system for orienting a multi-layered film structure of (1) at least one polymeric layer optimally orientable at a comparatively low temperature and (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature and being capable of being heated to said higher temperature by dielectric heating means;
said system comprising in combination:
7~
(a) means ~or heating said structure to said comparatively low temperature;
(b) dielectric ~eating means adapted to heat said layer (2) to said comparatively higher temperature while not substantially, directly increasing the temperature of layer (l); and (c) means for uniaxially orienting said structure while a temperature di~ferential exists between said layer (1) and layer (2), said di~ferential being of a magnitude at least generally corresponding to that between said comparatively low and said comparatively higher temperatures.
Preferably, the system also includes:
(d) further heating means for heating said structure to a second comparatively low temperature;
(e) further dielectric genera-ted heating means adapted to heat said layer (2) to a second comparatively higher temperature ~hile not substantially directly increasing the temperature of layer (l);
(f) Further orientiny means for biaxially orienting said structure while a temperature differential exists between layer (1) and layer (2), sald differential being of a magnitude at least generally corresponding to that between said second comparatively low and said second comparatively higher temperaturesO
In a further aspect~ the invention resides in a process for orienting a multi-layer layer structure comprising the steps of:
(a) preparing a multi-layered structure comprising (1) at least one polymeric layer optimally orientable at a comparatively low temperature and in association therewith (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature, and being capable of being heated to said hiyher temperature by dielectric heating means;
(b) heating said structure to said comparatively low temperature;
(c) while at said low temperature subjecting said structure to dielectric heating to heat said other polymeric layer to said comparatively higher temperature; and F-2064 ~3-(d) while a temperature differential exists between said layer (1) and layer (2), uniaxially orienting said structure; said differential being of a magnitude at least generally corresponding to that between said comparatively low and comparatively higher temperatures.
Preferably at least one layer of said structure is at least substantially free of polar substituents and at least one other layer of said structure contains at least a substantial number of polar substituents. The polar free layer can be a polyolefin, for example, polyethylene. The other layer or layers can be a thermoplastic layer containing polar substituents.
The present system and process take advantage of the fact that dielectric heating ene~gy will cause some polymers to increase in temperature quite rapidly while other polymers will heat, under the same conditions, at best, only slowly. This observation will permit, for example~ a dual layer laminate of a polymer which will not respond rapidly to dielectric heating and a polymer which will respond rapidly by increasing in temperature, to be uniaxially and biaxially oriented while each polymer is at a temperature which is optimal for its orientation. In order to accomplish this result the laminate is first heated to a temperature which is the optimum temperature for uniaxial or machine direction orientation of one of the polymers and while at this temperature the other layer is heated by dielectric heating .
The laminate is then uniaxially oriented. Thereafter, ~he temperature of this laminate is brought to or maintained at a temperature which is optimum for the biaxial orientation of the polymer which will not rapidly respond to dielectric heating and while at this temperature the laminate is subjected to sufficient dielectric heating to raise the other polymer to a temperature which is optimum for its biaxial orientation. When both layers are at these temperatures, the layer is then biaxially oriented and thereafter cooled to below these temperatures.
Dielectric heating as employed herein is understood to mean heating the polymer layers by placing them in a radio-frequency 76~
electric field. The films to be heated are positioned between flat or contoured electrodes which are connected to an oscillator which produces radio Frequency waves in the range of from 1 hertz to 10 megahertz with the electrodes at a potential of 1 to 20 kilovolts.
Some of the energy of the electric field between the electrodes is absorbed by the polymers but to a different degree in each polymer.
This facilitates bringing the different polymer layers to their respective orientation temperatures. Conventional radiant heat from, for example9 resistors can heat a laminate to the orientation temperature of one layer and dielectic heating can produce a temperature differential between the layers by only heating, or by heating to a greater extent, the other polymer layer. The temperature of said one layer may be to some extent affected by its pnysical association with the other layer heated by dielectric heating DUt this can be taken into consideration in preheating the laminate and in establishing the necessary optiumum orientation temperature differential.
Dielectric heating could also be employed at microwave frequencies, i.e. up to several thousand megahertz, by modifying the systems so as to employ a resonant cavity. This is not to be confused with microwave heating employing the use oF a wave guide or other microwaYe applicator.
It has been determined that the power requirements for heating certain polar substituent-containing polymer fiims to orientation terrlperature are well within the range of dielectric heating systems. Any suitable dielectric heating apparatus or system can be employed for establishing the temperature differential between associated polymers in the laminate. For example, after a conventional oven or heat chamber heats the laminate to a first ternperature, which is the optirnum orientation temperature For a nonpolar polymer layer of the laminate, the laminate can be passed through a dielectric heating apparatus such as a Model CP10-~, equipped with a 3.7 Kw power source~ available from Thermex Inc., 8ay Shore, New York. The laminate is then uniaxially oriented using any .~
7~
suitable means, e.g. differential speed rollers which can stretch the films up to 5 times and more. Thereafter, the laminate is heated to the optimum biaxially orientation temperature of the nonpolar film in a heat cham~er and then the temperature differential for biaxial orientation is established by means of the dielectric heating apparatus. Biaxial orientation is immediately effected by any suitable means, e.g. a T.M. Long orienter, followed by cooling.
It has been determined that 8 Kw of power can heat a 0.8 mil (0.02 mm) polyvinylidene chloride layer in a 30 inch (76 cm) wide web travelling at 500 feet/minute (15.2 m/minute) to a temperature which is 30F (17C) above of that of a polyethylene web bonded thereto.
This temperature differential will permit the biaxial orientation of both layers at their respective optimal orientation temperatures.
The invention is illustrated by the following examples.
Example I
A five layer, 30 inch (76 cm) wide film is prepared composed of (1) a 14 mil (0.35 mm) film of polyethylene homopolymer, (2) a 1.8 mil (0.045 mm) layer of CXA 3101 adhesive, an ethylene-vinyl acetate terpolymer from DuPont Co., (3) a }.5 mil (0.088 mm) film of polyvinylidene chloride (4) a 1.8 mil (0.0045 mm) layer of CXA 3101 adhesive and (5) a 14 mil (0.35 mm) layer of pGlyethylene homopolymer. This film is machine direction (MD) oriented at a temperature of about 210F (99C) using differential speed rollers to produce an MD stretching of 5 times. The MO oriented laminate is then transverse direction (TD) oriented 7 times on a T.M. Long orienter at a temperature of about 230F (110C). The resulting product will evidence haziness, some holes, thick and thin spots, and, overall, less than optimum physical properties.
*TxadenElr~
7~
F-20~i4 -6-ample II
~ ~ilm identical to that in Example I is MD oriented 5 times at 210F (99C). This film, while preheated to a temperature of about 215F (102C), (a sui~able temperature ~or TD orientation of polyethylene) is passed through a dielectric heating apparatus of 8 Kw output. The dielectric heating energy is applied for 2 seconds which is sufficient to raise the polyvinylidene chloride film to 234-260F
(110-127C), which is a suitable TD orientation temperature. The laminate is immediately TD oriented on a T.M. Long orienter to an extent of 7 times. The resulting laninate will evidence good biaxial orientation and physical characteristics.
It is to be understood that in the foregoing example the machine direction (MD) orientation can be accomplished by ~irst heating the laminate, for example~ by radiant heat to a temperature which is optimal for the MD orientation of the polyethylene layer and thereafter while at this temperature the dielectrlc heating unit can be employed to optimally heat the polyvinylidene chloride layer to its MD orientation temperature.
In the laminate ~or biaxial orientation, any orientable film which does not read11y increase in temperature in response to dielectric hneating energy is contemplated as at least one of the layers thereof. Ex~mples of such films include polyolefin films, e.g.
polyethylene, polypropylene, polybutylene, and ole~in copolymers, such as/ ethylene propylene copolymers. Any film which is biaxially orientable and which will readily respond to the energy generated by a dielectric heating unit so as to rapidly increase in temperature is contemplated ~or the other layer of the structure. ~roadly9 any polymer containing polar substituents which will respond to such energy and cause the ~ilm to rapidly increase in temperature is contemplated. Examples of such films include polyvinylidene chloride, ~olyvinyl aloohol poly~er~l ethylene-vin~l alcohol oopolyn~rs, polyamides, polyethers and polyesters.
~.~
71~
It also is contemplated to employ film laminates which respond to dielectric heating energy with an increase in temperature and exhibit a differential in temperature between that of each film, each film being at a temperature which is optimum for its orientation. Thus, the structures to be oriented include laminates of non-polar films with polar films and, în some instances, polar films with polar fiLms.
~-2064 -1-SYSTEM A D PROCESS FOR ORIENTING A MULTI-LAYER
FILM STRUCTURE
The present invention relates to a system and process for orienting a multi-layer film structure.
The uniaxial and biaxial orientation of polymer films is a common commercial operation. Such orientation improves the physical properties of the films such as, flexibility, Elmendorf tear strength, elongation, tensile-strength, Mullen burst strength, impact strength and cold strength propertiesO The desired orientation is accomplished by subjecting the polymer film to longitudinal and/or transverse tensile stress at a temperature somewhat above the second order transition temperature or the glass transition temperature thereof. A
problem is however encountered when orienting a multi-layer film laminate of different polymeric films, ~or example, a film composed of a polyethylene layer bonded by an adhesive to a polyvinylidene chloride film which in turn is adhesively bonded to a second polyethylene film. The core layer, i.e. the polyvinylidene chloride film, has a higher softening point than the polyethylene film and, thus, the structure must be heated above the ideal or optimum orientation temperature for the polyethylene film. On orientation this will result in either a hazy film with less than optimum physical properties or a film with little or no orientation or, in the worst casq, a non-processible film, which is to say, a film so hot that it splits during orientation, resulting in no film at all. It is, therefore, an object o~ the present invention to minimize or alleviate this problem.
Accordingly, the invention resides in one aspect in a system for orienting a multi-layered film structure of (1) at least one polymeric layer optimally orientable at a comparatively low temperature and (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature and being capable of being heated to said higher temperature by dielectric heating means;
said system comprising in combination:
7~
(a) means ~or heating said structure to said comparatively low temperature;
(b) dielectric ~eating means adapted to heat said layer (2) to said comparatively higher temperature while not substantially, directly increasing the temperature of layer (l); and (c) means for uniaxially orienting said structure while a temperature di~ferential exists between said layer (1) and layer (2), said di~ferential being of a magnitude at least generally corresponding to that between said comparatively low and said comparatively higher temperatures.
Preferably, the system also includes:
(d) further heating means for heating said structure to a second comparatively low temperature;
(e) further dielectric genera-ted heating means adapted to heat said layer (2) to a second comparatively higher temperature ~hile not substantially directly increasing the temperature of layer (l);
(f) Further orientiny means for biaxially orienting said structure while a temperature differential exists between layer (1) and layer (2), sald differential being of a magnitude at least generally corresponding to that between said second comparatively low and said second comparatively higher temperaturesO
In a further aspect~ the invention resides in a process for orienting a multi-layer layer structure comprising the steps of:
(a) preparing a multi-layered structure comprising (1) at least one polymeric layer optimally orientable at a comparatively low temperature and in association therewith (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature, and being capable of being heated to said hiyher temperature by dielectric heating means;
(b) heating said structure to said comparatively low temperature;
(c) while at said low temperature subjecting said structure to dielectric heating to heat said other polymeric layer to said comparatively higher temperature; and F-2064 ~3-(d) while a temperature differential exists between said layer (1) and layer (2), uniaxially orienting said structure; said differential being of a magnitude at least generally corresponding to that between said comparatively low and comparatively higher temperatures.
Preferably at least one layer of said structure is at least substantially free of polar substituents and at least one other layer of said structure contains at least a substantial number of polar substituents. The polar free layer can be a polyolefin, for example, polyethylene. The other layer or layers can be a thermoplastic layer containing polar substituents.
The present system and process take advantage of the fact that dielectric heating ene~gy will cause some polymers to increase in temperature quite rapidly while other polymers will heat, under the same conditions, at best, only slowly. This observation will permit, for example~ a dual layer laminate of a polymer which will not respond rapidly to dielectric heating and a polymer which will respond rapidly by increasing in temperature, to be uniaxially and biaxially oriented while each polymer is at a temperature which is optimal for its orientation. In order to accomplish this result the laminate is first heated to a temperature which is the optimum temperature for uniaxial or machine direction orientation of one of the polymers and while at this temperature the other layer is heated by dielectric heating .
The laminate is then uniaxially oriented. Thereafter, ~he temperature of this laminate is brought to or maintained at a temperature which is optimum for the biaxial orientation of the polymer which will not rapidly respond to dielectric heating and while at this temperature the laminate is subjected to sufficient dielectric heating to raise the other polymer to a temperature which is optimum for its biaxial orientation. When both layers are at these temperatures, the layer is then biaxially oriented and thereafter cooled to below these temperatures.
Dielectric heating as employed herein is understood to mean heating the polymer layers by placing them in a radio-frequency 76~
electric field. The films to be heated are positioned between flat or contoured electrodes which are connected to an oscillator which produces radio Frequency waves in the range of from 1 hertz to 10 megahertz with the electrodes at a potential of 1 to 20 kilovolts.
Some of the energy of the electric field between the electrodes is absorbed by the polymers but to a different degree in each polymer.
This facilitates bringing the different polymer layers to their respective orientation temperatures. Conventional radiant heat from, for example9 resistors can heat a laminate to the orientation temperature of one layer and dielectic heating can produce a temperature differential between the layers by only heating, or by heating to a greater extent, the other polymer layer. The temperature of said one layer may be to some extent affected by its pnysical association with the other layer heated by dielectric heating DUt this can be taken into consideration in preheating the laminate and in establishing the necessary optiumum orientation temperature differential.
Dielectric heating could also be employed at microwave frequencies, i.e. up to several thousand megahertz, by modifying the systems so as to employ a resonant cavity. This is not to be confused with microwave heating employing the use oF a wave guide or other microwaYe applicator.
It has been determined that the power requirements for heating certain polar substituent-containing polymer fiims to orientation terrlperature are well within the range of dielectric heating systems. Any suitable dielectric heating apparatus or system can be employed for establishing the temperature differential between associated polymers in the laminate. For example, after a conventional oven or heat chamber heats the laminate to a first ternperature, which is the optirnum orientation temperature For a nonpolar polymer layer of the laminate, the laminate can be passed through a dielectric heating apparatus such as a Model CP10-~, equipped with a 3.7 Kw power source~ available from Thermex Inc., 8ay Shore, New York. The laminate is then uniaxially oriented using any .~
7~
suitable means, e.g. differential speed rollers which can stretch the films up to 5 times and more. Thereafter, the laminate is heated to the optimum biaxially orientation temperature of the nonpolar film in a heat cham~er and then the temperature differential for biaxial orientation is established by means of the dielectric heating apparatus. Biaxial orientation is immediately effected by any suitable means, e.g. a T.M. Long orienter, followed by cooling.
It has been determined that 8 Kw of power can heat a 0.8 mil (0.02 mm) polyvinylidene chloride layer in a 30 inch (76 cm) wide web travelling at 500 feet/minute (15.2 m/minute) to a temperature which is 30F (17C) above of that of a polyethylene web bonded thereto.
This temperature differential will permit the biaxial orientation of both layers at their respective optimal orientation temperatures.
The invention is illustrated by the following examples.
Example I
A five layer, 30 inch (76 cm) wide film is prepared composed of (1) a 14 mil (0.35 mm) film of polyethylene homopolymer, (2) a 1.8 mil (0.045 mm) layer of CXA 3101 adhesive, an ethylene-vinyl acetate terpolymer from DuPont Co., (3) a }.5 mil (0.088 mm) film of polyvinylidene chloride (4) a 1.8 mil (0.0045 mm) layer of CXA 3101 adhesive and (5) a 14 mil (0.35 mm) layer of pGlyethylene homopolymer. This film is machine direction (MD) oriented at a temperature of about 210F (99C) using differential speed rollers to produce an MD stretching of 5 times. The MO oriented laminate is then transverse direction (TD) oriented 7 times on a T.M. Long orienter at a temperature of about 230F (110C). The resulting product will evidence haziness, some holes, thick and thin spots, and, overall, less than optimum physical properties.
*TxadenElr~
7~
F-20~i4 -6-ample II
~ ~ilm identical to that in Example I is MD oriented 5 times at 210F (99C). This film, while preheated to a temperature of about 215F (102C), (a sui~able temperature ~or TD orientation of polyethylene) is passed through a dielectric heating apparatus of 8 Kw output. The dielectric heating energy is applied for 2 seconds which is sufficient to raise the polyvinylidene chloride film to 234-260F
(110-127C), which is a suitable TD orientation temperature. The laminate is immediately TD oriented on a T.M. Long orienter to an extent of 7 times. The resulting laninate will evidence good biaxial orientation and physical characteristics.
It is to be understood that in the foregoing example the machine direction (MD) orientation can be accomplished by ~irst heating the laminate, for example~ by radiant heat to a temperature which is optimal for the MD orientation of the polyethylene layer and thereafter while at this temperature the dielectrlc heating unit can be employed to optimally heat the polyvinylidene chloride layer to its MD orientation temperature.
In the laminate ~or biaxial orientation, any orientable film which does not read11y increase in temperature in response to dielectric hneating energy is contemplated as at least one of the layers thereof. Ex~mples of such films include polyolefin films, e.g.
polyethylene, polypropylene, polybutylene, and ole~in copolymers, such as/ ethylene propylene copolymers. Any film which is biaxially orientable and which will readily respond to the energy generated by a dielectric heating unit so as to rapidly increase in temperature is contemplated ~or the other layer of the structure. ~roadly9 any polymer containing polar substituents which will respond to such energy and cause the ~ilm to rapidly increase in temperature is contemplated. Examples of such films include polyvinylidene chloride, ~olyvinyl aloohol poly~er~l ethylene-vin~l alcohol oopolyn~rs, polyamides, polyethers and polyesters.
~.~
71~
It also is contemplated to employ film laminates which respond to dielectric heating energy with an increase in temperature and exhibit a differential in temperature between that of each film, each film being at a temperature which is optimum for its orientation. Thus, the structures to be oriented include laminates of non-polar films with polar films and, în some instances, polar films with polar fiLms.
Claims (8)
1. A system for orienting a multi-layered film structure of (1) at least one polymeric layer optimally orientable at a comparatively low temperature and (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature and being capable of being heated to said higher temperature by dielectric heating means; said system comprising in combination:
(a) means for heating said structure to said comparatively low temperature;
(b) dielectric heating means adapted to heat said layer (2) to said comparatively higher temperature while not substantially, directly increasing the temperature of layer (1); and (c) means for uniaxially orienting said structure while a temperature differential exists between said layer (1) and layer (2), said differential being of a magnitude at least generally corresponding to that between said comparatively low and said comparatively higher temperatures.
(a) means for heating said structure to said comparatively low temperature;
(b) dielectric heating means adapted to heat said layer (2) to said comparatively higher temperature while not substantially, directly increasing the temperature of layer (1); and (c) means for uniaxially orienting said structure while a temperature differential exists between said layer (1) and layer (2), said differential being of a magnitude at least generally corresponding to that between said comparatively low and said comparatively higher temperatures.
2. A system as claimed in claim 1 and further comprising:
(d) further heating means for heating said structure to a second comparatively low temperatuare;
(e) further dielectric heating means adapted to heat said layer (2) to a second comparatiavely higher temperature while not substantially directly increasing the temperature of layer (1);
(f) further orienting means for biaxially orienting said structure while a temperature differential exists between said layer (1) and layer (2), said differential being of a magnitude at least generally corresponding to that between said second comparatively low and said second comparatively higher temperatures.
(d) further heating means for heating said structure to a second comparatively low temperatuare;
(e) further dielectric heating means adapted to heat said layer (2) to a second comparatiavely higher temperature while not substantially directly increasing the temperature of layer (1);
(f) further orienting means for biaxially orienting said structure while a temperature differential exists between said layer (1) and layer (2), said differential being of a magnitude at least generally corresponding to that between said second comparatively low and said second comparatively higher temperatures.
3. A process for orienting a multi-layer film structure comprising the steps of:
(a) preparing a multi-layered structure comprising (1) at least one polymeric layer optimally orientable at a comparatively low temperature and in association therewith (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature, and being capable of being heated to said higher temperature by dielectric heating means;
(b) heating said structure to said comparatively low temperature;
(c) while at said low temperature subjecting said structure to dielectric heating to heat said other polymeric layer to said comparatively higher temperature; and (d) while a temperature differential exists between said layer (1) and layer (2), uniaxially orienting said structure; said differential being of a magnitude at least generally corresponding to that between said comparatively low and comparatively higher temperatures.
(a) preparing a multi-layered structure comprising (1) at least one polymeric layer optimally orientable at a comparatively low temperature and in association therewith (2) at least one other polymeric layer optimally orientable at a comparatively higher temperature, and being capable of being heated to said higher temperature by dielectric heating means;
(b) heating said structure to said comparatively low temperature;
(c) while at said low temperature subjecting said structure to dielectric heating to heat said other polymeric layer to said comparatively higher temperature; and (d) while a temperature differential exists between said layer (1) and layer (2), uniaxially orienting said structure; said differential being of a magnitude at least generally corresponding to that between said comparatively low and comparatively higher temperatures.
4. The process as claimed in claim 3 and further comprising the steps of:
(e) reheating said structure to a comparatively low temperature;
(f) while at said low temperature subjecting said structure to dielectric heating to heat said layer (2) to a comparatively higher temperature while not substantially directly increasing the temperature of layer (1); and (g) while a temperature differential exists between said layer (1) and layer (2) biaxially orienting said structure, said differential being of a magnitude at least generally corresponding to that between said second comparatively low and said second comparatively higher temperatures.
=
(e) reheating said structure to a comparatively low temperature;
(f) while at said low temperature subjecting said structure to dielectric heating to heat said layer (2) to a comparatively higher temperature while not substantially directly increasing the temperature of layer (1); and (g) while a temperature differential exists between said layer (1) and layer (2) biaxially orienting said structure, said differential being of a magnitude at least generally corresponding to that between said second comparatively low and said second comparatively higher temperatures.
=
5. A process as claimed in claim 3 wherein layer (1) is at least substantially free of polar substituents and layer (2) contains at least a substantial number of polar substituents.
6. A process as claimed in claim 5 wherein layer (1) is a polyolefin and layer (2) is a thermoplastic polar substituent-containing polymer.
7. A process as claimed in claim 6 wherein layer (2) is a member selected from polyvinylidene chloride, polyvinyl alcohol, an ethylene-vinyl alcohol copolymer, a polyamide, a polyether and a polyester.
8. A process as claimed in claim 3 or claim 4 wherein said structure is bonded together by means of at least one adhesive layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/454,208 US4472330A (en) | 1982-12-29 | 1982-12-29 | System and process for simultaneously orienting the films of a film laminate |
| US454,208 | 1989-12-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1199769A true CA1199769A (en) | 1986-01-28 |
Family
ID=23803732
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000442337A Expired CA1199769A (en) | 1982-12-29 | 1983-12-01 | System and process for orienting a multi-layer film structure |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4472330A (en) |
| EP (1) | EP0113204B1 (en) |
| JP (1) | JPS59135125A (en) |
| CA (1) | CA1199769A (en) |
| DE (1) | DE3378260D1 (en) |
| ES (1) | ES528471A0 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5055355A (en) * | 1983-08-01 | 1991-10-08 | Allied-Signal Inc. | Oriented film laminates of polyamides and ethylene vinyl alcohol copolymers |
| DE3802146C1 (en) * | 1988-01-26 | 1989-02-23 | Battenfeld Extrusionstechnik Gmbh, 4970 Bad Oeynhausen, De | |
| DE8903609U1 (en) * | 1989-03-22 | 1989-05-18 | Hoechst Ag, 6230 Frankfurt, De | |
| US5164268A (en) * | 1990-03-09 | 1992-11-17 | The Dow Chemical Company | Oriented coextruded barrier films of polyvinylidene chloride copolymers |
| US5248470A (en) * | 1990-03-09 | 1993-09-28 | The Dow Chemical Company | Process of biaxially orienting coextruded barrier films of polyvinylidene chloride and an alkyl acrylate |
| IT1314223B1 (en) * | 1999-11-16 | 2002-12-06 | Tecno Coating Eng Srl | METHOD AND PLANT FOR THE BIORIENTATION OF THERMOPLASTIC-MULTILAYER MATERIALS. |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1127076A (en) * | 1965-12-08 | 1968-09-11 | Ici Ltd | Improved oriented films |
| FR2109357A5 (en) * | 1970-10-07 | 1972-05-26 | Doyen Leon | Sheet moulding process - using simultaneous partial surface and core melting for heavy propile moulding |
| US4022646A (en) * | 1971-11-26 | 1977-05-10 | Du Pont Of Canada Limited | Process for the manufacture of co-oriented laminated ethylene polymer films |
| US4217161A (en) * | 1976-08-10 | 1980-08-12 | Toyo Seikan Kaisha Limited | Process for making a container |
| DE2833189C2 (en) * | 1978-07-28 | 1984-09-20 | Brückner - Maschinenbau Gernot Brückner GmbH & Co KG, 8221 Siegsdorf | Method for longitudinally stretching an at least two-layer thermoplastic plastic film and device for carrying out the method |
| US4274900A (en) * | 1978-08-30 | 1981-06-23 | W. R. Grace & Co. | Multi-layer polyester/polyolefin shrink film |
| CH641406A5 (en) * | 1979-07-30 | 1984-02-29 | Tetra Pak Dev | HEAT-SEALABLE LAMINATE AND METHOD FOR THE PRODUCTION THEREOF. |
| GB2055855A (en) * | 1979-08-07 | 1981-03-11 | Ici Ltd | Heat-treating polyolefin films |
-
1982
- 1982-12-29 US US06/454,208 patent/US4472330A/en not_active Expired - Fee Related
-
1983
- 1983-12-01 CA CA000442337A patent/CA1199769A/en not_active Expired
- 1983-12-06 DE DE8383307400T patent/DE3378260D1/en not_active Expired
- 1983-12-06 EP EP83307400A patent/EP0113204B1/en not_active Expired
- 1983-12-28 ES ES528471A patent/ES528471A0/en active Granted
- 1983-12-28 JP JP58252341A patent/JPS59135125A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3378260D1 (en) | 1988-11-24 |
| US4472330A (en) | 1984-09-18 |
| EP0113204B1 (en) | 1988-10-19 |
| JPS59135125A (en) | 1984-08-03 |
| EP0113204A3 (en) | 1986-02-19 |
| ES8501673A1 (en) | 1984-12-01 |
| EP0113204A2 (en) | 1984-07-11 |
| ES528471A0 (en) | 1984-12-01 |
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