GB873220A - Polypropylene films and methods for their production - Google Patents
Polypropylene films and methods for their productionInfo
- Publication number
- GB873220A GB873220A GB4031358A GB4031358A GB873220A GB 873220 A GB873220 A GB 873220A GB 4031358 A GB4031358 A GB 4031358A GB 4031358 A GB4031358 A GB 4031358A GB 873220 A GB873220 A GB 873220A
- Authority
- GB
- United Kingdom
- Prior art keywords
- film
- polypropylene
- treatment
- shrink
- allowed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
- B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
-
- 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
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
-
- 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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Abstract
A process is described for making a polypropylene film of substantially uniform thickness in which at least 75% by weight of the polypropylene is insoluble in boiling n-heptane, and in which the polypropylene shows preferential molecular orientation (as determined by X-ray diffraction) with the molecular chain axes in the plane of the film, the molecules of polypropylene in the amorphous regions of the film being sufficiently free from internal strains so that the film has a linear shrinkage of not greater than 6% when heated for 1 min. at 120 DEG C., and the degree of molecular orientation being such that the film has a breaking tensile stress of at least 18,000 p.s.i., in any direction in the plane of the film, when measured on a specimen prepared by using a stamping cutter according to B.S.S. 903 Part A2 (1956) type C specimen at 20 DEG C. in two directions substantially at right angles substantially simultaneously. In the process, polypropylene film, sheet or tube in which at least 75% by weight of the polypropylene is insoluble in boiling n-heptane, made by melt-extrusion and quenching, is passed through a narrow zone in which it is heated rapidly to a temperature in the range 120 DEG -170 DEG C., at which it may be uniformly drawn but below the crystalline melting point of the polypropylene, and is freely drawn during or immediately after such passage in at least the direction along the length of the film and, before, during, or after such drawing, is stretched transversely such that the area of the undrawn film is increased 16-100 times, and is then heattreated at from 75 DEG -170 DEG C., preferably 145 DEG -160 DEG C., the degree of crystallinity of the film before drawing and the drawing temperature, rate and ratio and heat-treatment conditions being so chosen that the product conforms to the above criteria regarding linear shrinkage and breaking tensile stress. By rapid heating is meant heating by, e.g., infra-red radiation for at most 5 seconds, and by free drawing is meant drawing between a feeding means and a haul-off means. During heat-treatment the film should not be allowed to shrink in any direction by more than 15%. Alternatively, a two-stage heattreatment may be used, the film being allowed to shrink in the second stage, which may be effected at from 110 DEG -130 DEG C. Undrawn tubular film may be drawn in two directions substantially at right angles substantially simultaneously, and the heat-treatment stage may be effected in a continuous process in which the film is prevented from lateral contraction by internal pressure and from longitudinal contraction by means of feed and haul-off rollers. Alternatively, during heat-treatment, the diameter of the inflated tabular film is allowed to shrink while longitudinal contraction is substantially prevented. Specification 840,191 is referred to.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB4031358A GB873220A (en) | 1958-12-15 | 1958-12-15 | Polypropylene films and methods for their production |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB4031358A GB873220A (en) | 1958-12-15 | 1958-12-15 | Polypropylene films and methods for their production |
Publications (1)
Publication Number | Publication Date |
---|---|
GB873220A true GB873220A (en) | 1961-07-19 |
Family
ID=10414286
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB4031358A Expired GB873220A (en) | 1958-12-15 | 1958-12-15 | Polypropylene films and methods for their production |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB873220A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3214503A (en) * | 1962-09-28 | 1965-10-26 | Hercules Powder Co Ltd | Uniaxial orientation of polypropylene film |
US3217073A (en) * | 1962-04-26 | 1965-11-09 | Eastman Kodak Co | Process for the manufacture of biaxially oriented polypropylene film |
US3382306A (en) * | 1964-06-12 | 1968-05-07 | Hercules Inc | Process of forming elastic polypropylene film |
US5152946A (en) * | 1991-01-30 | 1992-10-06 | Hercules Incorporated | Producing low shrink packaging film |
US10753919B2 (en) * | 2015-02-27 | 2020-08-25 | Dow Global Technologies Llc | Methods and systems for measuring the forces of a shrink film |
-
1958
- 1958-12-15 GB GB4031358A patent/GB873220A/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3217073A (en) * | 1962-04-26 | 1965-11-09 | Eastman Kodak Co | Process for the manufacture of biaxially oriented polypropylene film |
US3214503A (en) * | 1962-09-28 | 1965-10-26 | Hercules Powder Co Ltd | Uniaxial orientation of polypropylene film |
US3382306A (en) * | 1964-06-12 | 1968-05-07 | Hercules Inc | Process of forming elastic polypropylene film |
US5152946A (en) * | 1991-01-30 | 1992-10-06 | Hercules Incorporated | Producing low shrink packaging film |
US10753919B2 (en) * | 2015-02-27 | 2020-08-25 | Dow Global Technologies Llc | Methods and systems for measuring the forces of a shrink film |
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