EP0343211A1 - Polypropylene films - Google Patents

Polypropylene films

Info

Publication number
EP0343211A1
EP0343211A1 EP88909800A EP88909800A EP0343211A1 EP 0343211 A1 EP0343211 A1 EP 0343211A1 EP 88909800 A EP88909800 A EP 88909800A EP 88909800 A EP88909800 A EP 88909800A EP 0343211 A1 EP0343211 A1 EP 0343211A1
Authority
EP
European Patent Office
Prior art keywords
biaxially oriented
polypropylene
resin
films
oriented polypropylene
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.)
Pending
Application number
EP88909800A
Other languages
German (de)
French (fr)
Inventor
Blair Grieve Wilson Syme
Allan John Crighton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Akzo Nobel Films Holding Ltd
Original Assignee
Courtaulds Films and Packaging Holdings Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=27263670&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0343211(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Priority claimed from GB8726814A external-priority patent/GB8726814D0/en
Application filed by Courtaulds Films and Packaging Holdings Ltd filed Critical Courtaulds Films and Packaging Holdings Ltd
Publication of EP0343211A1 publication Critical patent/EP0343211A1/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films 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
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10—Homopolymers or copolymers of propene
    • 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
    • B32B38/0012—Mechanical treatment, e.g. roughening, deforming, stretching
    • B32B2038/0028—Stretching, elongating
    • 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
    • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
    • B32B2309/02—Temperature
    • 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
    • B32B2323/00—Polyalkenes
    • B32B2323/10—Polypropylene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
    • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
    • C08J2323/10—Homopolymers or copolymers of propene
    • C08J2323/12—Polypropene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
    • C08L29/10—Homopolymers or copolymers of unsaturated ethers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L35/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least one other carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L35/08—Copolymers with vinyl ethers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L57/00—Compositions of unspecified polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C08L57/02—Copolymers of mineral oil hydrocarbons

Definitions

  • This invention concerns polymeric films and in particular oriented polypropylene films.
  • Biaxially oriented polypropylene homopolymer films have shown wide acceptance as packaging materials. However, for certain applications such films do not exhibit satisfactory properties, in particular for twist wrap or other instances where crease retention or dead " fold are required. Thus for twist wrap polypropylene homopolymer films have been found to be inferior to films of regenerated cellulose, the polypropylene films tending to untwist to an unacceptable degree. In some cases, untwisting can be sufficient that the wrapped article falls out of its wrapper.
  • West German Offenlegunsschrift 3535472 also describes polypropylene films for twist wrap applications, the films containing from 10 to 40 weight percent of a low molecular weight terpene resin. These films are biaxially oriented and have an elastic modulus of at least 3000MPa in both directions.
  • a biaxially oriented polypropylene film containing from 1 to 40 percent by weight of a hydrocarbon resin, the resin being substantially miscible with the polypropylene, and the film having a crease retention of at least 50% as measured by ASTM D920-49.
  • Films of the present invention have good crease retention of at least 50 percent, in particular at least 60 percent, and more particularly at least 70 percent, as measured by ASTM D920-49.
  • films of the present invention have shown good twist retention, for example values of at least 1.0 as measured by the method described in British Patent Specification 1231861 have been achieved.
  • hydrocarbon resin is used herein to refer not only to resins consisting of carbon and hydrogen only but to resins containing other atoms provided that when present such atoms do not significantly adversely affect the ability of the resins to impart crease retention to polypropylene films.
  • Hydrocarbon resins which can be used in accordance with the present invention can be selected from the terpene polymers, hydrogenated synthetic resins and compatible rosins disclosed in British Patent Specifications 993387 and 1231861. Hydrogenated synthetic terpene resins are usually preferred because they tend to be colorless or water-white compared with resins based on naturally occurring terpenes which tend to be yellow. In general it is preferred to use resins based on alicyclic terpenes.
  • the amount of hydrocarbon resin present is from 1 to 40, preferably from 10 to 25, and advantageously from 15 to 20 percent by weight based on the combined weight of the- polypropylene and the hydrocarbon resin.
  • the polypropylene is preferably a polypropylene homopolymer having a melt flow index (ASTM 1238 at 230°C under Condition L) of from 1 to 10 dg/min, and more preferably from 2 to 5 dg/min.
  • ASTM 1238 at 230°C under Condition L
  • Films of the present invention are biaxially oriented, and good crease retention characteristics, in particular of at least 50% as measured by ASTM D920-49, have been achieved by effecting stretching in the transverse direction at a temperature of at least 10, preferably at least 15, and more particularly at least 20 Centigrade degrees below the crystalline melting point of the polypropylene.
  • Such temperatures are substantially below those conventionally used in the art for orienting polypropylene film in the transverse direction.
  • Analogous films of polypropylene without the hydrocarbon resin being present would be expected to fracture under such stretching conditions.
  • conventional temperatures can be used in the machine direction.
  • a web of polypropylene homopolymer containing from 1 to 40 percent by weight of hydrocarbon resin is melt extruded, for example on to a chill roller, and then stretched in the machine direction, i.e. in the direction of extrusion, for example using heated rollers. Stretching is preferably effected at a- temperature of from 85 to 140°C, and more preferably from 90 to 120°C. The degree of stretch is preferably from 3.0 to 8.0:1, and more preferably from 4.0 to 6.0:1.
  • the mono-axially oriented film is then preferably oriented in the transverse direction using a stenter.
  • Preferred stretch ratios in the transverse direction are from ' 5.0 to 16.0:1, more particularly from 7.0 to 12.0:1.
  • films of the present invention can be provided with one or more further polymeric layers, for example to provide printable and/or heat sealable films.
  • Such layers can be produced, for example, by coextrusion with a base web of the polypropylene containing the hydrocarbon resin.
  • further polymeric layers which can be provided include those produced from polymers containing units derived from at least two of ethylene, propylene and but-1-ene.
  • Other polymeric layers which can be used include polyethylene containing units derived from at least one of hex-l-ene r oct-1-en.e and 4-methylpent-l-ene. Mixtures of such polymers can also be used.
  • Films of the present invention can include one or more additives known in the art, for example they can contain antistatic and/or slip agents.
  • specific materials which can be included with the hydrocarbon resin and/or in a further polymeric layer include silica, glycerol monostearate, bis-ethoxylated amines, fatty acid amides, e.g. erucamide, and polydimethylsiloxanes.
  • organic or inorganic fillers in the polypropylene used to form films of the present invention.
  • examples of organic fillers which can be used include polyamides and polyesters, and examples of inorganic fillers which can be used include calcium carbonate, talc, barium sulfate and clays-.
  • the filler particles can have particle sizes of from 1 to 20 microns.
  • the filler can be present in amounts of from 1 to 30 percent by weight of the film.
  • the temperature stability of films of the present invention can be improved by subjecting them to heat treatment, for example at 130 to 160°C. 'This can be beneficial where it is desired to effect heat sealing of the films.
  • films of the present invention can be provided with a metal layer, for example by lamination or vapour deposition of a metal, e.g. to produce a layer of aluminum.
  • Corona discharge treatment can be used to improve the printability of the films.
  • the thickness of films of the present invention is preferably from 20 to 40 microns, advantageously about 25 microns. If other polymeric layers are present, they preferably have a thickness of from 1 to 10 microns.
  • Films of the present invention in addition to showing good crease retention have shown increased stiffness compared with biaxially oriented polypropylene homopolymer film of the same thickness and produced under conventional processing conditions but without the hydrocarbon resin. Crease retention values in excess of 70 percent in both the machine and transverse directions (as measured by ASTM D920-49) have been achieved compared with less than 30 percent for conventional film. In addition, rigidity as measured by BS2782 (method 232) has been observed to be almost doubled in both the machine and transverse directions compared with conventional film of the same thickness.
  • a polypropylene homopolymer of melt flow index 3.0 was coextruded through a street die at 240°C. with a layer on each side of a random copolymer of propylene and ethylene containing 4% by weight of units derived from ethylene.
  • the two outer layers formed about 4% of the total weight of the sheet.
  • the extruded three layer web was chilled to 30°C using a conventional water cooled chill roll and water bath. The web was then heated to 100°C using heated rollers and then stretched in the longitudinal direction by 350%. The web was thereafter heated to 160°C " , and stretched by 900% in the transverse direction.
  • a polypropylene homopolymer of melt flow index 3.0 was compounded with 15 percent of a hydrogenated C-9 terpolymer of alpha-methyl styrene, vinyl toluene and indene (Arkon P125 - Arakawa Chemical Co., Japan), and extruded through a sheet die at 240°C.
  • the extruded polymer was chilled to 30 °C using a conventional water cooled chill roll and water bath.
  • the resulting cast web was heated to 100°C using heated rollers and then stretched in the longitudinal direction by 350%.
  • the web was thereafter cooled, reheated to 110°C, and stretched by 900% in the transverse direction.
  • a flat web of the polypropylene homopolymer used in Example 1 was coextruded with a layer on each side of a random copolymer of propylene and ethylene containing 4% by weight of units derived from ethylene.
  • the two outer layers formed about 4% of the total weight of the sheet.
  • Example 2 After chilling and longitudinal stretching of the web as in Example 1, it was stretched by 1000% in the transverse direction by means of a stenter frame oven at a temperature of 140°C. The film was then annealed at 130°C while allowing 8% reduction in width to improve its dimensional stability.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Laminated Bodies (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Materials For Medical Uses (AREA)

Abstract

This invention concerns biaxially oriented polypropylene films containing from 1 to 40 percent by weight of a hydrocarbon resin, the resin being substantially miscible with the polypropylene, and the film having a crease retention of at least 50% as measured by ASTM D920-49. The hydrocarbon resin is preferably a terpene resin, a hydrogenated synthetic resin or a compatible rosin. Crease retention values in excess of 70% have been achieved in particular by orienting the films at a temperature of at least 10 Centigrade degrees below the crystalline melting point of the polypropylene.

Description

POLYPROPYLENE FILMS
This invention concerns polymeric films and in particular oriented polypropylene films.
Biaxially oriented polypropylene homopolymer films have shown wide acceptance as packaging materials. However, for certain applications such films do not exhibit satisfactory properties, in particular for twist wrap or other instances where crease retention or dead "fold are required. Thus for twist wrap polypropylene homopolymer films have been found to be inferior to films of regenerated cellulose, the polypropylene films tending to untwist to an unacceptable degree. In some cases, untwisting can be sufficient that the wrapped article falls out of its wrapper.
It has been proposed in British Patent Specification 1231861 to produce biaxially oriented polypropylene films containing from 5 to 30% by weight of a terpene polymer, a compatible hydrogenated hydrocarbon resin, or a compatible rosin derivative, each having a softening point above 70 °C, orientation in the longitudinal or machine direction being to a greater degree than in the transverse direction. Such films are said to show twist retention.
West German Offenlegunsschrift 3535472 also describes polypropylene films for twist wrap applications, the films containing from 10 to 40 weight percent of a low molecular weight terpene resin. These films are biaxially oriented and have an elastic modulus of at least 3000MPa in both directions.
While these previous proposals appear to offer polypropylene films with twist wrap characteristics, neither provides a film which has commercially satisfactory properties.
According to the present invention there is provided a biaxially oriented polypropylene film containing from 1 to 40 percent by weight of a hydrocarbon resin, the resin being substantially miscible with the polypropylene, and the film having a crease retention of at least 50% as measured by ASTM D920-49.
Films of the present invention have good crease retention of at least 50 percent, in particular at least 60 percent, and more particularly at least 70 percent, as measured by ASTM D920-49.
In addition to good crease retention, films of the present invention have shown good twist retention, for example values of at least 1.0 as measured by the method described in British Patent Specification 1231861 have been achieved. The term hydrocarbon resin is used herein to refer not only to resins consisting of carbon and hydrogen only but to resins containing other atoms provided that when present such atoms do not significantly adversely affect the ability of the resins to impart crease retention to polypropylene films.
Hydrocarbon resins which can be used in accordance with the present invention can be selected from the terpene polymers, hydrogenated synthetic resins and compatible rosins disclosed in British Patent Specifications 993387 and 1231861. Hydrogenated synthetic terpene resins are usually preferred because they tend to be colorless or water-white compared with resins based on naturally occurring terpenes which tend to be yellow. In general it is preferred to use resins based on alicyclic terpenes.
The amount of hydrocarbon resin present is from 1 to 40, preferably from 10 to 25, and advantageously from 15 to 20 percent by weight based on the combined weight of the- polypropylene and the hydrocarbon resin.
The polypropylene is preferably a polypropylene homopolymer having a melt flow index (ASTM 1238 at 230°C under Condition L) of from 1 to 10 dg/min, and more preferably from 2 to 5 dg/min.
Films of the present invention are biaxially oriented, and good crease retention characteristics, in particular of at least 50% as measured by ASTM D920-49, have been achieved by effecting stretching in the transverse direction at a temperature of at least 10, preferably at least 15, and more particularly at least 20 Centigrade degrees below the crystalline melting point of the polypropylene. Such temperatures are substantially below those conventionally used in the art for orienting polypropylene film in the transverse direction. Analogous films of polypropylene without the hydrocarbon resin being present would be expected to fracture under such stretching conditions. However, conventional temperatures can be used in the machine direction.
In a preferred method of producing films of the present invention, a web of polypropylene homopolymer containing from 1 to 40 percent by weight of hydrocarbon resin is melt extruded, for example on to a chill roller, and then stretched in the machine direction, i.e. in the direction of extrusion, for example using heated rollers. Stretching is preferably effected at a- temperature of from 85 to 140°C, and more preferably from 90 to 120°C. The degree of stretch is preferably from 3.0 to 8.0:1, and more preferably from 4.0 to 6.0:1.
The mono-axially oriented film is then preferably oriented in the transverse direction using a stenter. Preferred stretch ratios in the transverse direction are from'5.0 to 16.0:1, more particularly from 7.0 to 12.0:1.
If desired, films of the present invention can be provided with one or more further polymeric layers, for example to provide printable and/or heat sealable films. Such layers can be produced, for example, by coextrusion with a base web of the polypropylene containing the hydrocarbon resin. Examples of further polymeric layers which can be provided include those produced from polymers containing units derived from at least two of ethylene, propylene and but-1-ene. Other polymeric layers which can be used include polyethylene containing units derived from at least one of hex-l-ener oct-1-en.e and 4-methylpent-l-ene. Mixtures of such polymers can also be used.
Films of the present invention can include one or more additives known in the art, for example they can contain antistatic and/or slip agents. Examples of specific materials which can be included with the hydrocarbon resin and/or in a further polymeric layer include silica, glycerol monostearate, bis-ethoxylated amines, fatty acid amides, e.g. erucamide, and polydimethylsiloxanes.
It is also possible to include organic or inorganic fillers in the polypropylene used to form films of the present invention. Examples of organic fillers which can be used include polyamides and polyesters, and examples of inorganic fillers which can be used include calcium carbonate, talc, barium sulfate and clays-. The filler particles can have particle sizes of from 1 to 20 microns. The filler can be present in amounts of from 1 to 30 percent by weight of the film.
The temperature stability of films of the present invention can be improved by subjecting them to heat treatment, for example at 130 to 160°C. 'This can be beneficial where it is desired to effect heat sealing of the films.
Other post orientation treatment steps known in the art can also be effected. Thus films of the present invention can be provided with a metal layer, for example by lamination or vapour deposition of a metal, e.g. to produce a layer of aluminum. Corona discharge treatment can be used to improve the printability of the films.
The thickness of films of the present invention is preferably from 20 to 40 microns, advantageously about 25 microns. If other polymeric layers are present, they preferably have a thickness of from 1 to 10 microns.
Films of the present invention in addition to showing good crease retention have shown increased stiffness compared with biaxially oriented polypropylene homopolymer film of the same thickness and produced under conventional processing conditions but without the hydrocarbon resin. Crease retention values in excess of 70 percent in both the machine and transverse directions (as measured by ASTM D920-49) have been achieved compared with less than 30 percent for conventional film. In addition, rigidity as measured by BS2782 (method 232) has been observed to be almost doubled in both the machine and transverse directions compared with conventional film of the same thickness.
The following Examples are given by way of illustration only. All parts are b -weight unless stated otherwise, and all melt flow index values are according to ASTM 1238 at 230°C under Condition L.
Example 1
A polypropylene homopolymer of melt flow index 3.0 was coextruded through a street die at 240°C. with a layer on each side of a random copolymer of propylene and ethylene containing 4% by weight of units derived from ethylene. The two outer layers formed about 4% of the total weight of the sheet.
The extruded three layer web was chilled to 30°C using a conventional water cooled chill roll and water bath. The web was then heated to 100°C using heated rollers and then stretched in the longitudinal direction by 350%. The web was thereafter heated to 160°C", and stretched by 900% in the transverse direction.
The resultant film after cooling had the properties listed in Table 1. M.D. signifies in the machine direction, and T.D. signifies in the transverse direction. Example 2
A polypropylene homopolymer of melt flow index 3.0 was compounded with 15 percent of a hydrogenated C-9 terpolymer of alpha-methyl styrene, vinyl toluene and indene (Arkon P125 - Arakawa Chemical Co., Japan), and extruded through a sheet die at 240°C. The extruded polymer was chilled to 30 °C using a conventional water cooled chill roll and water bath. The resulting cast web was heated to 100°C using heated rollers and then stretched in the longitudinal direction by 350%. The web was thereafter cooled, reheated to 110°C, and stretched by 900% in the transverse direction.
The resultant film after cooling had te properties listed in Table 1.
Example 3
A flat web of the polypropylene homopolymer used in Example 1 was coextruded with a layer on each side of a random copolymer of propylene and ethylene containing 4% by weight of units derived from ethylene. The two outer layers formed about 4% of the total weight of the sheet.
After chilling and longitudinal stretching of the web as in Example 1, it was stretched by 1000% in the transverse direction by means of a stenter frame oven at a temperature of 140°C. The film was then annealed at 130°C while allowing 8% reduction in width to improve its dimensional stability.
The resultant film after cooling had the properties listed in Table 1. TABLE 1
Property Example 1 Example 2 Example 3 (Comparison)
Thickness (micron) 30 30 25
Crease retention (%, ASTM D920-49) - M.D. 16 65 70
- T.D. 26 66 74

Claims

1. A biaxially oriented polypropylene film containing from 1 to 40 percent by weight of a hydrocarbon resin, the resin being substantially miscible with the polypropylene, and the film having a crease retention of at least 50% as measured by ASTM D920-49.
2. A biaxially oriented polypropylene film according to claim 1, where in the film has a crease retention of at least 60% as measured by ASTM D920-49.
3. A biaxially oriented polypropylene film according to claim 2, where in the film has a crease retention of at least 70% as measured by ASTM D920-49.
4. A biaxially oriented polypropylene film according to any of the preceding claims, wherein the film has a twist retention of at least 1.0.
5. A biaxially oriented polypropylene film according to any of the preceding claims, wherein the hydrocarbon resin is a terpene resin, a hydrogenated synthetic resin or a compatible rosin.
6. A biaxially oriented polypropylene film according to claim 5, wherein the hydrocarbon resin is a synthetic hydrogenated resin.
7. A biaxially oriented polypropylene film according to any of the preceding claims, having at least one further polymeric layer thereon.
8. A biaxially oriented polypropylene film according to any of the preceding claims, wherein the polypropylene contains an organic or inorganic filler.
9. A method of producing a biaxially oriented polypropylene film according to any of the preceding claims, the method comprising sequentially stretching a polymer web comprising polypropylene containing from 1 to 40 percent of a hydrocarbon resin, the stretching first being in the machine direction and then in the transverse direction, the stretching in the transverse direction being effected at a temperature of at least 10 Centigrade degrees below the crystalline melting point of the polypropylene.
10. A method according to claim 9, wherein the stretching in the transverse direction is effected at a temperature of at least 15 Centigrade degrees below the crystalline melting point of the polypropylene.
11. A method according to claim 9 or claim 10, wherein the stretching in the transverse direction is effected at a temperature of at least 20 Centigrade degrees below the crystalline melting point of the polypropylene.
EP88909800A 1987-11-16 1988-11-15 Polypropylene films Pending EP0343211A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB8726814 1987-11-16
GB8726814A GB8726814D0 (en) 1987-11-16 1987-11-16 Polypropylene films
GB8820025A GB8820025D0 (en) 1987-11-16 1988-08-23 Polypropylene films
GB8820025 1988-08-23
IN922DE1988 IN174624B (en) 1987-11-16 1988-10-25

Publications (1)

Publication Number Publication Date
EP0343211A1 true EP0343211A1 (en) 1989-11-29

Family

ID=27263670

Family Applications (2)

Application Number Title Priority Date Filing Date
EP88909800A Pending EP0343211A1 (en) 1987-11-16 1988-11-15 Polypropylene films
EP88310791A Expired - Lifetime EP0317276B2 (en) 1987-11-16 1988-11-15 Polypropylene films

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP88310791A Expired - Lifetime EP0317276B2 (en) 1987-11-16 1988-11-15 Polypropylene films

Country Status (12)

Country Link
EP (2) EP0343211A1 (en)
JP (1) JPH02504247A (en)
CN (1) CN1034164A (en)
AT (1) ATE111493T1 (en)
BR (1) BR8807306A (en)
CA (1) CA1313580C (en)
DE (1) DE3851505T3 (en)
FI (1) FI885285A (en)
GB (1) GB2212438B (en)
NO (1) NO885079L (en)
PH (1) PH25035A (en)
WO (1) WO1989004852A1 (en)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2071039T3 (en) * 1990-02-01 1995-06-16 Borden Inc MODIFIED POLYOLEFIN FILM WITH STABLE RETENTION OF ROLLING, COMPLETE FOLDING PROPERTIES AND BARRIER CHARACTERISTICS.
DE4031125A1 (en) * 1990-10-02 1992-04-09 Hoechst Ag BIAXIAL ORIENTED POLYPROPYLENE FILM FOR TURNING IN
DE4037417A1 (en) * 1990-11-24 1992-05-27 Hoechst Ag METALLIZABLE ROTARY WRAP FILM MADE OF BIAXIAL-ORIENTED POLYPROPYLENE
DE4335960A1 (en) * 1993-10-21 1995-04-27 Hoechst Ag Resin-containing, biaxially oriented polypropylene film, process for its production and its use
DE4417118A1 (en) * 1994-05-16 1995-11-23 Hoechst Ag High-strength, biaxially oriented polypropylene film
DE19536043A1 (en) * 1995-09-28 1997-04-10 Hoechst Ag Polyolefin film with cycloolefin polymer, process for its production and its use
ES2369529T3 (en) * 1995-12-22 2011-12-01 Mitsubishi Plastics, Inc. EXTENSIBLE FILM FOR FOOD PACKAGING.
US6087446A (en) 1996-03-20 2000-07-11 Hercules Incorporated Masterbatch formulations for polyolefin applications
DE19613960C5 (en) * 1996-04-09 2004-11-04 Borealis Gmbh Rupture foil
US6296983B1 (en) 1998-11-20 2001-10-02 Eastman Kodak Company Imaging element with improved twist warp
US6255395B1 (en) 1999-03-22 2001-07-03 Hercules Incorporated Masterbatches having high levels of resin
CA2423078A1 (en) * 2002-10-22 2004-04-22 Nicholas A. Farkas Scratch and mar resistant soft ethylene elastomer compositions
MX2019012181A (en) 2017-04-12 2020-02-10 Dow Global Technologies Llc Multilayer films containing a slip agent.

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1231861A (en) * 1968-04-03 1971-05-12
NL8003192A (en) * 1980-05-31 1982-01-04 Stamicarbon BIAXIALLY PROVIDED POLYPROPENE PLASTIC PRODUCTS AND METHOD FOR MANUFACTURING SUCH ARTICLES.
US4394235A (en) * 1980-07-14 1983-07-19 Rj Archer Inc. Heat-sealable polypropylene blends and methods for their preparation
JPS6147234A (en) * 1984-08-13 1986-03-07 Mitsubishi Plastics Ind Ltd Manufacturing method of heat shrinkable polypropylene film
DE3535472A1 (en) * 1985-10-04 1987-04-09 Hoechst Ag TRANSPARENT POLYPROPYLENE FILM FOR THE SWEET WRAP

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8904852A1 *

Also Published As

Publication number Publication date
FI885285A0 (en) 1988-11-15
WO1989004852A1 (en) 1989-06-01
CN1034164A (en) 1989-07-26
DE3851505T2 (en) 1995-01-12
GB2212438A (en) 1989-07-26
ATE111493T1 (en) 1994-09-15
CA1313580C (en) 1993-02-16
NO885079L (en) 1989-05-18
NO885079D0 (en) 1988-11-15
DE3851505D1 (en) 1994-10-20
FI885285A (en) 1989-05-17
EP0317276A2 (en) 1989-05-24
DE3851505T3 (en) 1999-01-28
GB8826594D0 (en) 1988-12-21
EP0317276A3 (en) 1989-05-31
PH25035A (en) 1991-01-28
JPH02504247A (en) 1990-12-06
EP0317276B2 (en) 1998-06-24
BR8807306A (en) 1990-03-13
GB2212438B (en) 1992-01-08
EP0317276B1 (en) 1994-09-14

Similar Documents

Publication Publication Date Title
AU709579B2 (en) High moisture barrier polypropylene-based film
US5212009A (en) Multi-layer transparent polyolefin film for application in shrink labelling
US5292561A (en) Transparent shrink film made from biaxially oriented polypropylene
JP2705975B2 (en) Transparent shrinkable film based on a mixture of polypropylene and a hydrocarbon resin, process for producing the same and shrinkable label made from the film
US5496600A (en) Matte biaxially oriented, multilayer polypropylene film and the use thereof
US5560885A (en) Process for the production of biaxially-oriented multilayer polyolefin film with a silk-matt finish
US5681650A (en) Heat-sealable, oriented, multilayer polyolefin film, process for the production thereof, and the use thereof
US5723088A (en) Process for the production of a heat-sealable oriented multilayer polyolefin film
EP0317276B1 (en) Polypropylene films
JPH10503976A (en) Uniaxially shrinkable biaxially oriented polyolefin film and method for producing the same
JPH0470987B2 (en)
GB2323323A (en) Polymeric label
CA2178113A1 (en) Biaxially oriented polypropylene film having a high area modulus
US5085943A (en) Polypropylene films
AU727361B2 (en) Oriented multilayer polyolefin film which is heat-sealable on both sides, its use, and process for its production
MXPA02011054A (en) Transparent, biaxially orientated polyolefinic film with improved bonding properties.
US5494717A (en) Matte, biaxially oriented, multilayer polypropylene film of high shrinkage, process for the production thereof, and the use thereof
JPH06316047A (en) Multilayer oriented heat-sealing polypropylene film having both good surface lubricity and improved shielding properties
US5246659A (en) Method of producing polyproplene films
GB2323325A (en) Heat shrinkable polyolefin film
US5484633A (en) Heat-sealable, oriented, multilayer polyolefin film, process for the production thereof, and the use thereof
JP2969657B2 (en) Polypropylene composite film and metallized polypropylene composite film
GB2212506A (en) Polypropylene films
AU621329B2 (en) Biaxially oriented polypropylene film containing 1-40 per cent hydrocarbon resin
JPH09302108A (en) Polypropylene resin composition for extrusion film and extrusion film using the same

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 19890818

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI NL SE

XX Miscellaneous (additional remarks)

Free format text: VERFAHREN ABGESCHLOSSEN INFOLGE VERBINDUNG MIT 88310791.4/0317276 (EUROPAEISCHE ANMELDENUMMER/VEROEFFENTLICHUNGSNUMMER) VOM 09.01.91.