Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
  • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
  • C08K5/1515—Three-membered rings
• • 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
  • 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
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
• • 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
  • C08L23/26—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment
  • C08L23/30—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment by oxidation

Definitions

• the present invention relates to a vinylidene chloride interpolymer possessing an improved combination of properties.
• this invention relates to an improved barrier resin comprising a mixture of a vinylidene chloride interpolymer and a unique combination of additives, which resin has improved barrier to atmospheric gases and has, after being subject to a heat history during processing, a reduced level of carbon contamination and good extrudability e:g., color.
• Vinylidene chloride interpolymers are well-known in the prior art.
• vinylidene chloride interpolymers have been produced by an emulsion or suspension polymerization process. Both the emulsion and suspension polymerization processes produce an aqueous dispersion of polymer particles having a relatively small particle diameter. The polymer particles are recovered from the aqueous dispersion by drying or other means for removing a majority of the aqueous phase.
• the practice has been to extrude the vinylidene chloride interpolymer directly from the form in which it is recovered.
• such compounds are fabricated mainly from vinylidene chloride interpolymers and an adequate amount of modifiers such as stabilizers, plasticizers, etc.
• the melt viscosity of the resin is sufficiently high that the load on the extruder screw is too large and the extruded compound is subject to thermal decomposition and discoloration due to the close proximation of the compound's thermal decomposition point and melting point.
• the decomposed interpolymer may generate an undesirable level of carbon contamination in the extrudate, which could have an effect upon the gas barrier of the extrudate.
• the present invention concerns a process for improving the extrudability of a thermally sensitive resin comprising the step of blending into a generally homogeneous mixture a vinylidene chloride interpolymer and a unique combination of additives which comprises an extrusion aid selected from the group consisting of oxidized polyethylene; oxidized polypropylene; or mixtures thereof, in an amount of from about 0.01 to about 0.5 weight percent; an ethylene-vinyl acetate copolymer present in an amount of from about 0.5 to about 2 weight percent; a paraffin wax present in an amount of from about 0.005 to about 1 weight percent; and an epoxidized oil or resin present in an amount of from about 0.1 to about 3 weight percent, all weight percentages being based on the total weight of the mixture.
• an extrusion aid selected from the group consisting of oxidized polyethylene; oxidized polypropylene; or mixtures thereof, in an amount of from about 0.01 to about 0.5 weight percent; an ethylene-vinyl acetate cop
• the present invention concerns a composition
• a composition comprising a generally homogeneous mixture of a vinylidene chloride interpolymer and a unique combination of additives which comprises an extrusion aid selected from the group consisting of oxidized polyethylene; oxidized polypropylene; or mixtures thereof, in an amount of from about 0.01 to about 0.5 weight percent; an ethylene-vinyl acetate copolymer present in an amount of from about 0.5 to about 2 weight percent; a paraffin wax present in an amount of from about 0.005 to about 1 weight percent; and an epoxidized oil or resin present in an amount of from about 0.1 to about 3 weight percent, all weight percentages being based on the total weight of the mixture.
• an extrusion aid selected from the group consisting of oxidized polyethylene; oxidized polypropylene; or mixtures thereof, in an amount of from about 0.01 to about 0.5 weight percent; an ethylene-vinyl acetate copolymer present in an amount of from about 0.5 to about
• Vinylidene chloride Interpolymers suitable for use in the present invention are those vinylidene chloride interpolymers formed from vinylidene chloride and an amount of one or more monoethylenically unsaturated monomers copolymerizable with vinylidene chloride.
• the vinylidene chloride interpolymers have selectively polymerized therein vinylidene chloride in an amount of from about 40 to about 98 weight percent, beneficially from about 50 to about 96 weight percent, and desirably from about 60 to about 94 weight percent, based on total weight of the vinylidene chloride interpolymer.
• the vinylidene chloride interpolymer is selected to comprise one or more monoethylenically unsaturated monomers copolymerizable with vinylidene chloride.
• the amount of monoethylenically unsaturated monomer is suitably from about 60 to about 2 weight percent, beneficially from about 50 to about 4 weight percent, and desirably from about 40 to about 6 weight percent, based on total weight of the vinylidene chloride interpolymer.
• Monoethylenically unsaturated monomers suitable for use in the present invention include vinyl chloride, alkyl acrylates, alkyl methacrylates, acrylic acid, methacrylic acid, itaconic acid, acrylonitrile, and methacrylonitrile.
• the ethylenically unsaturated monomers are desirably selected from the group consisting of vinyl chloride, alkyl acrylates, and alkyl methacrylates, the alkyl acrylates and alkyl methacrylates having from about 1 to about 8 carbon atoms per alkyl group.
• the alkyl acrylates and alkyl methacrylates preferably have from about 1 to about 4 carbon atoms per alkyl group.
• the alkyl acrylates and alkyl methacrylates are most preferably selected from the group consisting of methylacrylates, ethylacrylates, and methyl methacrylates.
• the vinylidene chloride interpolymers suitable for use in the present invention are well-known in the prior art.
• the vinylidene chloride interpolymer is generally formed through an emulsion or suspension polymerization process. Exemplary of such processes are U.S. Patents 2,558,728; 3,007,903; 3,642,743; and 3,879,359; .and the methods described by R. A. Wessling, in Polyvinylidene Chloride, Gordon and Breach Science Publishers, New York, 1977, Chapter 3; all of which are incorporated herein by reference.
• the monomeric materials are emulsified or suspended in an aqueous phase.
• the aqueous phase contains a polymerization initiator and a surface active agent capable of emulsifying or suspending the monomeric materials in the aqueous phase.
• the polymerization of the monomeric materials is usually carried out with heating and agitation.
• the resulting suspension or emulsion of vinylidene chloride interpolymer has a majority of an aqueous phase.
• the resultant polymeric material is vacuum stripped. Thereafter, the slurry is cooled down, unloaded and dewatered, and the resin Is collected and further dried.
• the inventors have found that a particular combination of additives yields a resin, in either powder or pellet form, which when extruded provides an article having good color characteristics, low carbon contamination, and low permeability to oxygen.
• the preferred vinylidene chloride interpolymer formulation comprises the following additives.
• An extrusion aid of oxidized polyethylene; oxidized polypropylene; or mixtures thereof is employed.
• Oxidized polyethylene and oxidized polypropylene are well-known in the prior art.
• Oxidized polyethylene and oxidized polypropylene are generally prepared by forming the ethylene or propylene polymer through methods well-known in the art, and subsequently exposing said polymer to oxygen at an elevated temperature and for a time sufficient to achieve the desired degree of oxidation.
• oxidized polyethylene is employed as an extrusion aid.
• Allied 629A oxidized polyethylene commercially available from Allied Corp., is the oxidized polyethylene.
• the oxidized polyethylene is incorporated into the vinylidene chloride interpolymer in the useful range of from about 0.01 to about 0.5 weight percent, preferably in the range of from about 0.02 to about 0.08 weight percent, most preferably in the range of from about 0.03 to about 0.04 weight percent.
• An ethylene-vinyl acetate copolymer is employed as an additional extrusion aid; suitably, EVA 3180 ethylene-vinyl acetate copolymer which contains about 28 percent vinyl acetate and is commercially available from E. I. DuPont de Nemours Co.
• the EVA 3180 or an equivalent ethylene-vinyl acetate copolymer is incorporated into the vinylidene chloride interpolymer in the range of from about 0.5 to about 2 weight percent.
• a paraffin wax is employed as an extrusion aid.
• a paraffin commercially available from Bohler Industries under the trade designation Bohler 1421, may be incorporated into the vinylidene chloride interpolymer.
• the paraffin wax is present in an amount in the range of from about 0.005 to about 1 weight percent, most preferably in the range of from about 0.1 to about 0.2 weight percent.
• Epoxidized oils and resins are suitably employed as plasticizers, stabilizers and lubricants; for example, Vikoflex 7177 epoxidized soybean oil which contains oxirane groups is commercially available from Viking Chemical Co.
• the Vikoflex 7177 epoxidized soybean oil or an equivalent epoxidized soybean oil is incorporated into the vinylidene chloride interpolymer in the range of from about 0.1 to about 3 weight percent, preferably, from about 0.5 to about 2 weight percent, and most preferably, from about 0.8 to about 1.2 weight percent.
• the additive package comprises an additive comprising at least one inorganic base.
• Preferred inorganic bases are magnesium hydroxide, tetrasodium pyrophosphate, magnesium oxide, and calcium hydroxy phosphate (commonly referred to tricalcium phosphate), with magnesium hydroxide being most preferred.
• An exemplary magnesium hydroxide is Kisuma 5B, commercially available from the Kyowa Chemical Co.
• the inorganic base When the inorganic base is included in the additive package, it is suitably present in. an amount of from about 0.01 to about 5 weight percent of the total mixture weight. Preferably, the inorganic base is present in an amount of from about 0.1 to about 4 weight percent of the total mixture weight. Most preferably, the inorganic base is present in an amount of from about 0.5 to about 2 weight percent of the total mixture weight.
• the inventors have found that a specific combination of additives provides particularly beneficial results.
• the combination comprises the following: an oxidized polyethylene, such as Allied 629A, in an amount of about 0.03 weight percent; an ethylene-vinyl acetate copolymer, such as EVA 3180, in an amount of about 0.65 weight percent; a paraffin wax, such as Bohler 1421, present in an amount of about 0.12 weight percent; an epoxidized oil, such as Vikoflex 7177, in an amount of about 1.0 weight percent; and magnesium hydroxide, such as Kisuma 5B, in an amount of about 0.65 weight percent.
• the exact quantities of the compounds of the additives blended with the vinylidene chloride interpolymer should be selected to provide a resin having an oxygen permeability according to the Dow permeability index of no more than about 0.09 units, the Dow index being calculated as follows: units are in (cc «mil)/(100 in 2 ⁇ day ⁇ atm), wherein cc is the cubic centimeters of oxygen, mil is the sample thickness, in 2 is the surface area of the sample, day represents a 24 hour time period, and atm is atmospheric pressure in atmospheres.
• the oxygen permeability of mixtures according to the present invention will be less than about 0.08 Dow unit.
• the selection of suitable proportions to satisfy the above criteria is known by skilled artisans.
• the additive package may contain additional additives well-known to those skilled in the art.
• additives which may be incorporated in the package are light stabilizers such as hindered phenol derivatives; pigments such as titanium dioxide and the like.
• light stabilizers such as hindered phenol derivatives
• pigments such as titanium dioxide and the like.
• Blending of the vinylidene chloride and the additive package can be accomplished by using conventional melt processing, as well as dry blending techniques.
• melt processing must be accomplished at a temperature below that at which decomposition of the vinylidene chloride interpolymer becomes significant.
• Conventional melt processing equipment which may be used includes heated two-roll compounding mills, Brabender mixers, Banbury mixers, single screw extruders, twin screw extruders, and the like. Desirable results are obtained when an extruder, either single screw or twin screw, is used for melt blending the vinylidene chloride interpolymer and the additives.
• Suitable dry blending equipment Includes Hobart mixers, Welex mixers, Henschel High Intensity mixers, and the like.
• the vinylidene chloride interpolymer and additive package is then extruded.
• the mixture is physically blended and then melt processed into any suitable final product.
• the mixture of vinylidene chloride interpolymer and additive package is pelletized.
• pellets or pellets refer to particles having a minimum cross-sectional dimension of at least 1/32 inch, beneficially of at least 1/16 inch, and preferably of at least 1/8 inch, said pellets suitably have a maximum cross-sectional dimension of at least 1/2 inch, beneficially of at least 3/8 inch, and preferably of at least 1/4 inch.
• Exemplary of a method suitable for use in forming the pellets of the mixture are extrusion through a strand die and pelletization by chopping the extruded strand into pellets.
• the process and composition according to the present invention improves the extrudability of the vinylidene chloride interpolymer and allows for the satisfactory extrusion of vinylidene chloride interpolymer pellets formed therefrom.
• the pellets are considered to possess improved extrudability when the mixture of vinylidene chloride interpolymer and additives can be formed into an article which possesses less carbon contamination and less discoloration than from pellets formed from the vinylidene chloride interpolymer alone.
• the process of the present invention can be used to form a variety of films or other articles.
• the films and articles are fabricated with conventional coextrusion, e.g, feedblock coextrusion, multimanifold die coextrusion, or combinations of the two; injection molding; extrusion molding; and lamination techniques.
• Articles formed therefrom include blown and cast, mono and multilayer, films; rigid and foam sheet; tubes; pipes; rods; fibers; and various profiles.
• Lamination techniques are particularly suited to produce multi-ply sheets.
• specific laminatng techniques include fusion, i.e., whereby self-sustaining lamina are bonded together by applications of heat and pressure; wet combining, i.e., whereby two or more plies are laminated using a tie coat adhesive, which is applied wet, the liquid driven off, and combining by subsequent pressure laminating in one continuous process; or by heat reactivation, i.e., combining a precoated film with another film by heating and reactivating the precoat adhesive so that it becomes receptive to bonding after subsequent pressure laminating.
• Exemplary articles include rigid containers used for the preservation of food, drink, medicine and other perishables. Such containers should have good mechanical properties, as well as low gas permeabilities to, for example, oxygen, carbon dioxide, water vapor, odor bodies or flavor bodies, hydrocarbons or agricultural chemicals. Most organic polymers such as the polyolefins, styrene polymers and the like, by themselves, do not possess sufficent resistance to transmission of atmospheric gases and vapors. Consequently, multilayer sheet structures employed in packaging materials have organic polymer skin layers laminated on each side of a vinylidene chloride interpolymer barrier layer, generally with glue layers used to promote adhesion between the barrier layer and dissimilar material layers.
• Articles formed from the preferred formulation exhibit decreased oxygen permeabilty.
• the present invention is illustrated in further detail by the following examples. The examples are for the purposes of illustration only, and are not to be construed as limiting the scope of the present invention. All parts and percentages are by weight unless otherwise specifically noted.
• Blends of vinylidene chloride are prepared with various additives as set forth in Table 1.
• a vinylidene chloride interpolymer is formed through a suspension polymerization process.
• the vinylidene chloride interpolymer is formed from a monomer mixture comprising about 94 weight percent vinylidene chloride and about 6 weight percent methyl acrylate, based on total monomer mixture weight, the copolymer has a weight average molecular weight of 100,000.
• the interpolymer produced as described above is melt blended into a generally homogeneous mixture with the various quantities of the following additives: (a) Vikoflex 7177 epoxidized soybean oil commercially available from Viking Chemical Co; (b) ethylene-vinyl acetate copolymer commercially available from E. I. DuPont de Nemours under the trade designation EVA 3180; (c) a paraffin wax commercially available from Bohler Industries under the trade designation Bohler 1421; and an oxidized polyethylene commercially available under the trade designation as Allied 629A from Allied Corp.
• the mixtures described immediately above are, in some examples, melt blended with one of the following inorganic bases: (a) magnesium hydroxide, commercially available from the Kyowa Chemical Co., under the trade designation Kisuma 5B; (b) tetrasodium pyrophospahate commercially available from Monsanto Chemical Co.; magnesium oxide, commercially available from Merck & Co., under the trade designation Maglite S 3331; and (d) calcium hydroxy phpsphate commercially available from Monsanto, under the trade designation polymer grade tricalcium phosphate.
• inorganic bases (a) magnesium hydroxide, commercially available from the Kyowa Chemical Co., under the trade designation Kisuma 5B; (b) tetrasodium pyrophospahate commercially available from Monsanto Chemical Co.; magnesium oxide, commercially available from Merck & Co., under the trade designation Maglite S 3331; and (d) calcium hydroxy phpsphate commercially available from Monsanto,
• the mixture of vinylidene chloride interpolymer and additives is pelletized. Pelletizing is accomplished using a commercially available strand die and cutter. The pellets have an average length of about 0.130 inch and an average diameter of about 0.145 inch.
• the pellets are extruded through a 2 1 /2" extruder having a length to diameter ratio of 21/1.
• the molten blend is extruded through a single tape die to form a tape which is tested.
• the decomposition of the extruded resin into carbon is determined on the root of the extruder screw heel, on the extruder die, and in the extrudate tape.
• pellets are extruded in a continuous process for a period of about 2 hours.
• the extent of carbon formation is qualitatively rated on a scale of 1 to 5 over a continous range of carbon buildup, wherein 1 represents generally no visible carbon on the surface and 5 represents a layer of carbon generally completely covering the surface.
• Carbon contamination in the extrudate tape is determined by counting specks of carbon over a one minute period every during the two hour extrusion trial.
• the extent of carbon formation is qualitatively rated on a scale of 1 to 5 over a continous range of carbon buildup, wherein 1 represents less than 20 carbon speck counts per minutes and 5 represents greater than 100 carbon specks counts per minute.
• the samples in examples are measured for oxygen permeability.
• the oxygen permeability of blends according to the present invention is measured according to a Dow permeability index, the Dow index being calculated as follows: units are in (cc ⁇ mil) /(100 in 2 ⁇ day ⁇ atm), wherein cc is the cubic centimeters of oxygen, mil is the sample thickness, in 2 is the surface area of the sample, day represents a 24 hour time period, and atm is atmospheric pressure in atmospheres.
• Oxygen permeability of the extrudate tapes is measured using an instrument commercially available from Modern Controls, Incorporated , under the trade designation Oxtran 1050. Oxygen permeability measurements are made at 23° Centigrade.
• VdMA All examples are carried out with a vinylidene chloride copolymer of 94 weight percent vinylidene chloride and 6 weight percent methyl acrylate, having a weight average molecular weight of 100,000.
• 2 OP oxidized polyethylene, commercially available from Allied Corp., under the trade designation Allied 629A. Weight percent is based upon the total mixture weight.
• 3 Wax paraffin wax, commercially available from Bohler Industries, under the trade designation Bohler 1421. Weight percent is based upon the total mixture weight.
• ESO epoxidized soybean oil, commercially available from Viking Chemical Company, under the trade designation Vikoflex 7177. Weight percent is based upon the total mixture weight.
• EVA ethylene-vinyl acetate, commercially available from E.I. DuPont de Nemours Co., under the trade designation EVA 3180. Weight percent is based upon the total mixture weight.
• Mg(OH) 2 magnesium hydroxide, commercially available from the Kyowa Chemical Co., under the trade designation Kisuma 5B;
• TSPP tetrasodium pyrophospahate commercially available from Monsanto Chemical Co.;
• TCP commercially available from Monsanto, under the trade designation polymer grade tricalcium phosphate. Weight percent is based upon the total mixture weight.
• Carbon contamination according to visual inspection of (a) the extruder screw, (b) the extruder die, and (3) the extrudate. Carbon formation on the screw and die is rated on a scale of 1 to 5 over a continous range of carbon buildup, wherein 1 represents generally no visible carbon on the surface and 5 a represents a layer of carbon generally completely covering the surface. Carbon contamination in the extrudate tape is qualitatively rated on a scale of 1 to 5 over a continous range of carbon buildup, wherein 1 represents less than 20 carbon speck counts per minutes and 5 represents greater than 100 carbon specks counts per minute.
• O 2 perm. oxygen permeabilty measured in cubic centimeters of oxygen times mils of thickness divided by the product of (a) 100, (b) area in square inches, (c) 24 hours and (d) the atmospheric pressure in atmospheres.
• compositions of the present invention possess good color characteristics, low carbon contamination, and low permeability to oxygen.

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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)
• Compositions Of Macromolecular Compounds (AREA)

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• 1988
  • 1988-10-11 CA CA000579707A patent/CA1329288C/en not_active Expired - Fee Related
  • 1988-10-11 AU AU29214/89A patent/AU629195B2/en not_active Ceased
  • 1988-10-11 EP EP19890901234 patent/EP0382792A4/en not_active Ceased
  • 1988-10-11 WO PCT/US1988/003516 patent/WO1989003412A1/en not_active Application Discontinuation
  • 1988-10-11 JP JP1501184A patent/JPH03501866A/ja active Pending
  • 1988-10-11 KR KR1019890701046A patent/KR970006904B1/ko active IP Right Grant

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