WO1991008260A1 - Melange extrudable a chaud, corps thermoplastique et sa fabrication - Google Patents

Melange extrudable a chaud, corps thermoplastique et sa fabrication Download PDF

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Publication number
WO1991008260A1
WO1991008260A1 PCT/US1990/006779 US9006779W WO9108260A1 WO 1991008260 A1 WO1991008260 A1 WO 1991008260A1 US 9006779 W US9006779 W US 9006779W WO 9108260 A1 WO9108260 A1 WO 9108260A1
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WIPO (PCT)
Prior art keywords
acrylic polymer
thermoplastic body
copolymer
methyl acrylate
film
Prior art date
Application number
PCT/US1990/006779
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English (en)
Inventor
Jeffrey Michael Schuetz
Original Assignee
Viskase Corporation
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
Application filed by Viskase Corporation filed Critical Viskase Corporation
Publication of WO1991008260A1 publication Critical patent/WO1991008260A1/fr

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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
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • 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
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L27/00—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 halogen; Compositions of derivatives of such polymers
    • C08L27/02—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 halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L27/04—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 halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
    • C08L27/08—Homopolymers or copolymers of vinylidene chloride
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/08—Homopolymers or copolymers of acrylic acid esters
    • 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
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B32B2307/734—Dimensional stability
    • B32B2307/736—Shrinkable

Definitions

  • This invention relates to a hot extrudable blend
  • thermoplastic body comprising vinylidene chloride-methyl acrylate copolymer and an acrylic polymer lubricant-type processing aid, a thermoplastic body having at least a discrete portion formed from the blend, and a method for preparing the thermoplastic body.
  • the latter may for example be a monolayer film formed from the hot extrudable blend, or a multilayer film having one layer as for example a core barrier formed from the blend.
  • Primal meat cuts, or primals are large cuts of meat, smaller, for example, than a side of beef, but larger than the ultimate cut that is sold at retail to the consumer.
  • Primal cuts are prepared at the slaughter house and are then shipped to a retail meat store or an institution such as a restaurant where they are butchered into small cuts of meat called sub-primal meat cuts or sub-primals. Sub-primals may also be prepared at the slaughter house. When primals and sub-primals are prepared at the slaughter house, they are usually packaged in such a way that air (i.e., oxygen) is prevented from contacting the meat during shipping and
  • One way to package primals and sub-primals so as to protect them from degradation due to moisture loss and contact with air is to shrink package them with a package material that has good barrier properties.
  • One such shrink packaging material that has good oxygen and moisture barrier properties is vinylidene chloride-vinyl chloride copolymer film.
  • processed meats is to employ a multilayer film having oxygen and moisture barrier properties, one layer of which is a vinylidene chloride-vinyl chloride copolymer film.
  • the other layer or layers of such a multilayer film are selected so as to provide the requisite low temperature properties and abrasion resistance which are lacking in vinylidene chloride-vinyl chloride film..
  • good barrier properties, abrasion resistance, and low temperature properties are not the only requirements for a film that is to be used for shrink packaging primal and sub-primal meat cuts.
  • the film must have been biaxially stretched in order to produce shrinkage characteristics sufficient to enable the film to heat shrink within a specified range of percentages, e.g., from about 15 to 60 percent at about 90°C, in both the machine and the transverse directions.
  • the film must also be heat sealable in order to be able to fabricate bags from the film and in order to heat seal the open mouths of the fabricated bags when the meat cut has been placed within the bag. Additionally, the heat sealed seams of the bags must not pull apart during the heat shrinking operation, the film must resigt puncturing by sharp edges such as bone edges during the heat shrinking operation, and there must be adequate adhesion between the several layers of the film so that delamination does not occur, either during the heat shrinking opera-tion or during exposure of the film to the relatively high temperatures that may be reached during shipping and storage of the film in the summer time.
  • multilayer films comprising a core layer of a vinylidene chloride copolymer, wherein the layer is a copolymer of a vinylidene chloride monomer and a vinyl chloride monomer, are known, for example, as disclosed in Brax et al, U.S. Pat Nos. 3,741,253 and 4,278,738; Baird et al, U.S. Pat No. 4,112,181; and Lustig et al Canadian Pat. No. 982,983.
  • Lustig et al U.S. Patent No. 4,737,391 teaches that the aforedescribed discoloration problem may be avoided by using vinylidene chloride-methyl acrylate copolymer as the barrier layer in shrinkable multilayer films.
  • the Lustig et al invention is based on the discovery that this particular copolymer does not significantly discolor from irradiation or sustained exposure to high temperatures.
  • acrylate copolymer is very temperature and shear sensitive during extrusion into a film. This extrusion can only be performed over a narrow temperature range without causing premature degradation of the polymer in the extruder or die. The premature degradation causes particles or gels of degraded material to exit from the extruder.
  • blending requires mixing equipment and to minimize separation by settling during storage, the blending is most effective when done
  • thermoplastic bodies having at least a discrete portion consisting essentially of
  • Example 1 Melting point is a function of composition and in the case of MA saran is directly related to the methyl acrylate content. Pure vinylidene chloride is neither stable or extrudable and the methyl acrylate is
  • Too much methyl acrylate in the copolymer reduces its crystallinity and diminishes the barrier properties of the copolymer.
  • copolymers such as MA saran cannot be effectively processed in the pure resin form. This is accomplished by the
  • additives include plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the resin and serve to reduce its viscosity when heated to the molten state. Suitable plasticizers - liquids which are absorbed by the
  • plasticizers include dibutyl sebacate and epoxidized soybean oil. Stabilizers are added to improve thermal stability of the copolymer in the heated molten condition. As a consequence the copolymer (with the added stabilizer) will take longer to degrade and ideally the time is extended beyond that occurring during processing.
  • the other major type of additive is generally termed a lubricant, and there are two varieties.
  • the internal type reduces heating due to friction within the copolymer during external heating and physically imparted movement of the individual copolymer molecules against each other.
  • the external type of processing aid affects the frictional contact between the copolymer's outer surface and the surrounding inner surface of the extrusion equipment.
  • the lubricant system of this invention is the external type, and provides lubrication between the copolymer and the
  • the acrylic polymer preferably has a weight average molecular weight (M ) of over 100,000.
  • Chromium plated stainless steel is the preferred PVC extruder screw and die construction material whereas nickel alloys are preferred for vinylidene chloride-methyl acrylate (MA saran) extruder screws and dies.
  • organo tins are used with PVC as for example butyl tin mercaptide.
  • these organo tins cannot be used with MA saran and stabilizers such as epoxidized soy bean oil and tetra sodium pyro phosphate ("TSPP") are commonly used as stabilizers in MA saran processing.
  • TSPP tetra sodium pyro phosphate
  • One object of this invention is to provide an MA saran resin with improved external lubrication during hot
  • thermoplastic body of desired shape a thermoplastic body of desired shape
  • a further object is to provide a hot extruded
  • thermoplastic body having at least a discrete MA saran portion, and characterized by lower metal adhesion and thermal degradation during extrusion.
  • a still further object is to provide a hot extruded MA saran biaxially oriented and heat shrinkable flexible film having good physical characteristics.
  • An additional object is to provide a hot extruded MA saran rigid member having good, physical characteristics.
  • Still another object is to provide an improved method for preparing a thermoplastic body having at least a
  • thermoplastic body having at least a discrete portion consisting essentially of vinylidene chloride-methyl acrylate copolymer with at least about 0.5 parts acrylic polymer per hundred weight of the copolymer.
  • the acrylic polymer is uniformly dispersed in the discrete portion as a lubricant-type processing aid, and is in sufficient quantity to provide both lower metal adhesion and thermal degradation of the vinylidene chloride-methyl acrylate copolymer during the extrusion than without the acrylic polymer.
  • the hot extruded thermoplastic body may be either rigid or flexible.
  • Rigid bodies include relatively thick walled (e.g. greater than 10 mils) sheets and containers of the type used for extended shelf life food storage.
  • Flexible bodies include relatively thin walled (e.g. less than 10 mils) films, especially the biaxially oriented heat
  • the discrete portion of the hot extruded thermoplastic body may for example be a layer of a multi-walled rigid container or a core layer of a multilayer film fabricated into an evacuable and sealable bag with an inner heat sealable layer in direct contact with the enclosed food and an outer layer formed of a material selected for its abuse resistance and general toughness.
  • the MA saran discrete portion may form the entire hot extruded thermoplastic body, as for example when a rigid container is hot extruded from a single die processing only essentially 100% MA saran.
  • the thermoplastic body may be a biaxially oriented heat
  • shrinkable monolayer film such as a meat casing.
  • Another aspect of the invention relates to a hot
  • extrudable blend comprising vinylidene chloride-methyl acrylate copolymer and at least about 0.5 parts acrylic polymer per hundred weight of the copolymer.
  • Still another aspect of the invention relates to a method for preparing a thermoplastic body having at least a discrete portion consisting essentially of vinylidene chloride-methyl acrylate copolymer.
  • the copolymer and at least about 0.5 parts acrylic polymer per hundred weight of the copolymer are blended together to form a substantially uniform mixture.
  • At least this blend is heated and extruded as the sole material in a particular extrusion flow path bounded by metal walls, to form a thermoplastic body with lower metal adhesion and reduced thermal degradation of the polymer mixture during the extrusion.
  • the MA saran-acrylate polymer mixture may be
  • thermoplastic polymers in separate flow paths which are adhered to each other in the molten state at the discharge end of the extruder.
  • a three layer film may be formed by coextruding an MA saran core barrier layer and separate thermoplastic polymer layers (as for example from ethylene vinyl acetate) on each side of the MA saran core barrier layer. The three hot extruded layers are then directly adhered to each other at the extruder discharge end in a multilayer die.
  • the MA saran-acrylate polymer mixture may be extruded as a monolayer film and used in this form.
  • the MA saran monolayer film comprises the entire thermoplastic bag.
  • the film may also be manufactured by the coating lamination process as for example described in Brax et al U.S. Patent No. 3,741,253.
  • the first layer is extruded by itself and then a second layer as for example the MA saran-acrylate polymer mixture is coated thereon.
  • a third layer may be coated on the opposite side of the second layer so that the second layer becomes a core and is enclosed between the first and third layers.
  • a pair of layers may be coextruded and one or more additional layers applied by coating lamination to this substrate.
  • the film embodiment of the invention is to be used in shrink wrapping a product as for example food, the film is oriented as by "tenter framing" or by bubble inflating.
  • cross- link at least the outer layer of a multilayer film or the entire film if the monolayer type. This may be done by adding crosslinking agents to the resin blend as for example peroxide or siloxane compounds. Alternatively, crosslinking may be accomplished by irradiation as for example with an electron beam, preferably at a level of at least 1 megarad (MR) and most preferably in the range of 2-5MR. Irradiation may be performed on a single layer such as the substrate layer of the multilayer film prepared by the coating
  • the entire multilayer film may be irradiated and preferably after biaxial
  • a typical extrusion line consists of a blender, a dryer, feed hopper, extruder (single or twin screw), die, quenching section, pull rolls, and winder or sheeter. Melt filters and metering pumps improve quality and uniformity.
  • the quench section may be a chilled casting drum, water bath or three-roll stock, depending on the material, sheet thickness and extrusion rate.
  • the vinylidene chloride-methyl acrylate copolymer molecular weight in the practice of this invention is preferably at least about 75,000 to readily achieve biaxial orientation (if desired) and film/sheet toughness, and up to about 130 , 000 for ease of extrudability .
  • the most preferred range is between about 90,000 and about 110,000 molecular weight.
  • the methyl acrylate content in the copolymer is preferably between about 5 weight percent for ease of extrudability and up to about 15 weight percent which is in the U.S. Federal Food and Drug Administration's limit.
  • the most preferred range for methyl acrylate content is between about 6 and about 10 weight percent in the copolymer with vinylidene chloride.
  • the hot extrudable blend of this invention may include other conventional additives such as slip agents, anti-blocking agents and pigments as is well known in the art.
  • the blend preferably contains less than 5 parts per hundred plasticizer based on the copolymer weight, in order to maximize the barrier properties of the vinylidene chloride-methyl acrylate copolymer. Also, the blend
  • Suitable acrylic polymers for the practice of this invention include those described in the aforementioned Harrop U.S. Patent No. 4,156,703. These acrylic polymers preferably have a weight average molecular weight M W of at least 100,000. Moreover, they are preferably
  • the ester may for example be selected from the group consisting of methyl methacrylate,
  • the ester is preferably a mixture in the C 1 to C 35 range. Still more preferably the
  • acrylic polymer is polymerized from a monomer system comprising at least 50% by weight methyl methacrylate and the remainder another acrylate.
  • the preferred acrylic polymer is the aforementioned ACRYLOID (now called PARALOID) K-175.
  • the acrylic polymer is present in a concentration of at least 0.5 parts per hundred weight copolymer. Significantly lower
  • the acrylic polymer is preferably below about 5 parts per hundred weight copolymer as excessive lubrication reduces the desired friction and shearing efficiency in the extruder.
  • the first outer layer is preferably an ethylene-vinyl acetate copolymer containing from about 9 to about 15 weight percent of vinyl acetate, based on the weight of the copolymer, said copolymer having a melt index of between about 0.1 and about 1.0 decigram per minute, and it may be selected from the group consisting of (a) a single ethylene-vinyl acetate copolymer and (b) a blend of ethylene-vinyl acetate copolymers having melt indices and vinyl acetate contents within the aforementioned ranges of values.
  • the second outer layer of this preferred thin flexible heat shrinkable three layer film comprises an ethylene-vinyl acetate copolymer selected from the group consisting of (a) an ethylene-vinyl acetate copolymer having a melt index of between about 0.1 and about 1.0 decigram per minute, and a vinyl acetate content of from about 18 weight percent, most preferably from about 10 to about 15 weight percent, based on the weight of said second ethylene-vinyl acetate
  • the blend (b) of said two ethylene-vinyl acetate copolymers has a vinyl acetate content of from about 3 to about 18 weight percent, and preferably from about 10 to about 15 weight percent, based on the weight of said copolymers.
  • one or both of the outer layers may be formed of ethylene-alpha olefin polymers as for example linear low density polyethylene (LLDPE) or very low density (sometimes referred to as ultra low density) polyethylene or mixtures thereof with EVA.
  • LLDPE linear low density polyethylene
  • ultra low density polyethylene sometimes referred to as ultra low density
  • the bag will have diminished puncture resistance.
  • the first outer layer will preferably have a thickness of from about 1.1 mils to about 2.0 mils; the core layer will preferably have a thickness of from about 0.20 mil to about 0.45 mil; and the second outer layer will preferably have a thickness of from about 0.4 mil to about 1.5 mils.
  • the thickness of the first outer layer which is the inner layer of the bag, is preferably within the aforementioned range because the sealing and processability properties of the film layer would otherwise be diminished.
  • the thickness of the core layer is preferably within the above-indicated range because the film would provide inadequate barrier properties of the core layer thickness is less than about 0.20 mil.
  • the preferred upper limit of 0.45 mil for the core layer is based on the barrier effectiveness needed for intended uses of the multilayer film.
  • the thickness of the second outer layer which is the outer layer of the bag, is preferably in the aforementioned range to provide desired toughness and puncture resistance and also keep the total thickness of the film in the range from about 1.75 mil to about 4.0 mils.
  • Bags suitable for the shrink packaging of primal and subprimal meat cuts and processed meats are provided from the aforedescribed heat shrinkable multilayer film.
  • the bags may be produced from this film by heat sealing.
  • the film is produced in the form of tubular film
  • bags can be produced therefrom by heat sealing one end of a length of the tubular film or by sealing both ends of the tube, then slitting one edge to form the bag mouth.
  • the film is made in the form of flat sheets, bags can be formed therefrom by heat sealing three edges of two
  • the surfaces which are heat sealed to each other to form seams are the aforedescribed first outer layers of the films.
  • the inner surface of the tube i.e. the surface which will be heat sealed to itself, will be the first outer layer of the film.
  • the flexible multilayer film is specifically described in the form of a three layer film, in its broadest context only two layers are required: the barrier layer and one outer layer. More than three layers are also
  • a five layer film comprising outer layers of polypropylene or ethylene-propylene
  • copolymer the aforedescribed blend as a barrier layer and an adhesive layer between each outer layer and the barrier layer.
  • the processing aid-containing copolymer formulations were also evaluated in kneading tests using a high intensity Brabender mixer, i.e. a Brabender Plasticorder torque rheometer maintained at 300°F with a No. 6 mixer roller head operated at 50 RPM.
  • the test procedure was to add 70 gms of resin-additive formulation to the mixer.
  • the torque was recorded for 10 minutes and the formulation removed.
  • the time for fusion torque to occur was measured along with fusion torque itself (in meter grams/sec).
  • fusion torque is a maximum value and a measure of maximum viscosity. As mixing is continued, the torque diminishes to a stable level, referred to as final torque which was measured after the
  • extrudate was examined for dark smears and black particles. Also, any throughput variation was observed. Based on these parameters, the extrusion performance was qualitatively rated between 1 (best performance) to 5 (poorest
  • a rating of 1 indicates that the waste rate in production would be very low and commercially acceptable based on previous experience, whereas a high rating indicates the likelihood of progressively increasing and unacceptable waste rate.
  • sample nos. 1 through 10 are 100% MA saran with various processing aids other than acrylic polymer and sample 11 is 75% MA saran - 25% vinylidene chloride, vinyl chloride copolymer with 0.1 pph.
  • polyethylene wax processing aid embodies the blend invention of aforementioned Schuetz U.S. Patent No. 4,798,751 and has proven satisfactory in commercial use. Accordingly, a 100% MA saran formulation with processing characteristics equivalent to sample 11 would represent a substantial improvement by eliminating the complexities and performance limitation of blending two resins.
  • Sample 12 is a 100% vinylidene chloride-vinyl chloride, (hereinafter sometimes referred to as "PVDC") 0.5 pph.
  • PVDC vinylidene chloride-vinyl chloride
  • sample 12 is also a basis for comparison and a 100% MA saran formulation with equivalent processing characteristics would represent a substantial improvement because it does not significantly degrade and discolor when exposed to moderate irradiation dosage.
  • Samples 13 through 18 are 100% MA saran formulations employing PARALOID K-175 acrylic polymer as the processing aid in concentrations between 0.5 and 5.0 pph. Accordingly, they are embodiments of the hot extrudable blend aspect of the invention. Referring now to sample 13, it provides an adhesion time of 10 minutes and an adhesion rating of 2 in the two-roll milling test. Of the other 100% MA saran formulations only sample 3 (5 pph. fluoroelastomer
  • any impurities in the form of particles may eventually cause bubble break if the extrudate is in the form of a tube which is inflated for orientation.
  • the overall extrusion performance rating of 1 for the acrylic polymer processing aid sample 13 is the same as the extrusion performance rating for 75% MA saran-25% PVDC sample 11 and 100% PVDC sample 12.
  • copolymer-processing aid formulations in terms of hot extrusion manufacturing characteristics.
  • processing aids used in the Example 1 tests are advertized by their manufacturers as suitable for inproving the processability of PVC resin. These include polyolefin waxes, calcium stearate, magnesium stearate and OP wax. As previously acknowledged, acrylic polymers such as PARALOID K-175 are also advertized for this purpose.
  • Example 1 demonstrates that their effectiveness as
  • the films were the three layer type and prepared by coextrusion with a MA saran core layer between two EVA layers, followed by biaxial orientation.
  • Two different MA saran formulations were used: sample 19 was very similar to sample 13 (Example 1) and contained 2.0 pph. PARALOID K-175 acrylic polymer processing aid.
  • Sample 20 was identical to sample 19 except that it did not include the acrylic polymer processing aid.
  • the three layer film compositions prepared from samples 19 and 20 were otherwise identical. The same extruder was used for both formulations.
  • the dies were the aforementioned Duranickel and the extruder screws formed of stainless steel.
  • Sample 20 was briefly extruded for comparison with sample 19. This formulation had relatively low throughput rate per extruder revolution, indicating poor feeding. Melt pressure variation was 12% with the only variation noted being due to screw rotation.
  • polymer-containing sample 19 were about 64-65% of the
  • Non-ASTM test method employed are described in the following discussion. Shrinkage values were obtained by measuring unrestrained shrink at 90°C for five seconds.
  • the dynamic puncture-impact test procedure is used to compare films for their resistance to bone puncture. It measures the energy required to puncture a test sample with a sharp bone end.
  • a Dynamic Ball Burst Tester Model No. 138, available from Testing Machines, Inc., Amityville, Long Island, NY, is used and a 3/8 inch diameter triangular trip, as aforedescribed, is installed on the tester probe arm and employed in this test procedure.
  • Tests were conducted using commercial extrusion equipment (substantially identical to the commercial extruder of Example 2) to compare the physical properties of 100% MA saran core layer, three layer film with the aforedescribed 75% MA
  • sample 21 The physical properties of sample 21 are summarized and compared with a 75% MA saran-25% PVDC core layer, three layer film sample 22 (which is very similar to sample 11) in Table C.
  • Table C demonstrates that an acrylic polymer processing aid-containing 100% MA saran core layer type three layer (EVA outer) film has physical properties fully equivalent to a commercially employed 75% MA saran-25% PVDC core layer, otherwise identical film. This includes about the same oxygen transmission despite the addition of acrylic
  • the extruder melting mechanism of the present invention was visually observed and found to be substantially different from the conventional melting mechanism of prior art PVDC-processing aid blend formulations. More specifically, these tests were performed in a 2 1/2 in. diameter 20:1 instrumented extruder operated at a constant screw speed of 13 RPM. The die and screw were constructed of Duranickel. The extruder was capable of being "crashed", an expression used in the art to describe a sequence whereby stable extrusion operation is first
  • formulation sample 12 (PVDC-0.5 mg.
  • PVDC melting began at screw flight 8 and was completed at screw flight 18.
  • the extruder melting mechanism or behavior for the 100% MA saran-acrylic polymer processing aid formulation was quite different, and in my experience unique. Instead of a gradual or progressive transition from solid resin to melt across the entire extruder cross-section, the as-formed thin melt pool initially surrounded the solid bed in ringlike fashion. Then during longitudinal movement towards the discharge end the melt pool became progressively larger, began penetrating the surrounded solids mass which became progressively smaller until it was completely dissolved in the melt. In this sequence, the MA saran-acrylic polymer blend first formed as a thin ring around the solid mass at flight 8, had penetrated the solid mass at flight 12 and total melting had occurred at flight 17. Although not fully understood, it is theorized that the acrylic polymer
  • processing aid was such an effective lubricant that there was very little shear force between the extruder walls and the external surface of the flowing mass. Accordingly, most of the melting occurred due to conductive heating from the extruder barrel and very little heating occurred due to shear.
  • Table D The data from these tests is summarized in Table D.
  • sample 23 was replaced with a blend without the inorganic stabilizer (sample 24) but otherwise identical to sample 23.
  • the bubble heat rate was reduced to the same level as with sample 19 and processing conditions remained very stable.
  • the throughput rate was 0.75% higher than with sample 19.
  • Example 5 along with Example 2 demonstrates that the invention permits higher throughput rates than with the prior art 75% MA saran-25% PVDC blend system and at stable operating conditions.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Laminated Bodies (AREA)

Abstract

Mélange extrudable à chaud comprenant un copolymère d'acrylate de chlorure de vinylidène-méthyle, ainsi qu'au moins 0,05 part de polymère acrylique exprimée en pourcentage en poids du copolymère. On utilise le mélange afin de préparer un corps thermoplastique ayant une partie discrète composée essentiellement du mélange. On prépare le corps thermoplastique par mélange des constituants du mélange, par chauffage et par extrusion d'au moins ledit mélange en tant qu'unique matière dans un chemin d'écoulement d'extrusion particulier limité par des parois en métal.
PCT/US1990/006779 1989-11-27 1990-11-27 Melange extrudable a chaud, corps thermoplastique et sa fabrication WO1991008260A1 (fr)

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US44168589A 1989-11-27 1989-11-27
US441,685 1989-11-27

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WO1991008260A1 true WO1991008260A1 (fr) 1991-06-13

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5202188A (en) * 1991-08-23 1993-04-13 W. R. Grace & Co.-Conn. Vinylidene chloride film
EP0604136A1 (fr) * 1992-12-17 1994-06-29 W.R. Grace & Co.-Conn. Film extrudable de chlorure Polyvinylidène
US5514473A (en) * 1992-10-23 1996-05-07 W.R. Grace & Co.-Conn. Barrier blend for use in food-packaging film
US5726229A (en) * 1994-11-18 1998-03-10 W. R. Grace & Co.-Conn. Vinylidene chloride composition and film with controlled gas permeability
US5759702A (en) * 1991-08-23 1998-06-02 W. R. Grace & Co.-Conn. Vinylidene chloride composition and film made therefrom
US6045924A (en) * 1996-06-19 2000-04-04 Cryovac, Inc. Film from a vinylidene chloride copolymer containing blend
EP2325251A1 (fr) * 2009-11-20 2011-05-25 Dow Global Technologies LLC Structures imprimables de chlorure de polyvinylidène à mono- ou multicouche
JP2018177890A (ja) * 2017-04-06 2018-11-15 旭化成株式会社 塩化ビニリデン系共重合体樹脂組成物
US11396595B2 (en) 2012-10-05 2022-07-26 Sk Saran Americas Llc Vinylidene chloride copolymer composition for barrier film

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US4828891A (en) * 1987-02-02 1989-05-09 Viskase Corporation Four-layer puncture resistant film
US4863784A (en) * 1987-05-28 1989-09-05 Viskase Corporation Multilayer film containing very low density polyethylene
US4959416A (en) * 1987-05-04 1990-09-25 The Dow Chemical Company Polymeric blend composition

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US4828891A (en) * 1987-02-02 1989-05-09 Viskase Corporation Four-layer puncture resistant film
US4959416A (en) * 1987-05-04 1990-09-25 The Dow Chemical Company Polymeric blend composition
US4863784A (en) * 1987-05-28 1989-09-05 Viskase Corporation Multilayer film containing very low density polyethylene
US4863784C1 (en) * 1987-05-28 2001-05-01 Bt Commercial Corp Multilayer film containing very low density polyethylene

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5759702A (en) * 1991-08-23 1998-06-02 W. R. Grace & Co.-Conn. Vinylidene chloride composition and film made therefrom
US5202188A (en) * 1991-08-23 1993-04-13 W. R. Grace & Co.-Conn. Vinylidene chloride film
US5514473A (en) * 1992-10-23 1996-05-07 W.R. Grace & Co.-Conn. Barrier blend for use in food-packaging film
US5914194A (en) * 1992-12-17 1999-06-22 Cryovac, Inc. Extrudable vinylidene chloride polymeric film
AU675958B2 (en) * 1992-12-17 1997-02-27 W.R. Grace & Co.-Conn. Extrudable vinylidene chloride polymeric film
EP0604136A1 (fr) * 1992-12-17 1994-06-29 W.R. Grace & Co.-Conn. Film extrudable de chlorure Polyvinylidène
US5726229A (en) * 1994-11-18 1998-03-10 W. R. Grace & Co.-Conn. Vinylidene chloride composition and film with controlled gas permeability
US6133352A (en) * 1994-11-18 2000-10-17 Cryovac, Inc. Film with controlled gas permeability
US6045924A (en) * 1996-06-19 2000-04-04 Cryovac, Inc. Film from a vinylidene chloride copolymer containing blend
EP2325251A1 (fr) * 2009-11-20 2011-05-25 Dow Global Technologies LLC Structures imprimables de chlorure de polyvinylidène à mono- ou multicouche
CN102070862A (zh) * 2009-11-20 2011-05-25 陶氏环球技术公司 可印刷的单层聚偏二氯乙烯结构
CN102070862B (zh) * 2009-11-20 2015-04-22 陶氏环球技术公司 可印刷的单层聚偏二氯乙烯结构
US11396595B2 (en) 2012-10-05 2022-07-26 Sk Saran Americas Llc Vinylidene chloride copolymer composition for barrier film
JP2018177890A (ja) * 2017-04-06 2018-11-15 旭化成株式会社 塩化ビニリデン系共重合体樹脂組成物

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CA2030695A1 (fr) 1991-05-28
JPH04503227A (ja) 1992-06-11
JP2947931B2 (ja) 1999-09-13

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