Stock material or miscellaneous articles – Composite – Of addition polymer from unsaturated monomers
Reexamination Certificate
1999-04-01
2003-03-04
Tarazano, D. Lawrence (Department: 1773)
Stock material or miscellaneous articles
Composite
Of addition polymer from unsaturated monomers
C264S173190, C156S244110, C427S355000
Reexamination Certificate
active
06528174
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to certain polymeric blends containing olefinic bisoleamides such as EBO (N,N-ethyleneBisOleamide) and ethylene copolymers such as ethylene vinyl acetate (EVA). The composition provides enhanced film forming properties in the production of monolayer or multilayer film products.
2. Description of Related Art
Ethylene vinyl acetate copolymers (EVA) are known and have a wide variety of applications in the industrial arts. EVA copolymers find commercial use in flexible, heat sealable, functional, and decorative hot-melt and solvent-applied coatings; as wax additives to impart toughness, flexibility, and adhesion; as blending resins to impart flexibility to brittle materials; and as a component of hot-melt and solvent-applied adhesives. It is also known that the vinyl acetate percentage in these copolymers can be varied and many such resins are sold under the trademark ELVAX® by E. I. du Pont de Nemours and Company. The present inventors have found that the film forming properties and processibility of this resin can vary with increasing vinyl acetate percentage and that high vinyl acetate copolymers (e.g. greater than about 0% VA by weight) can cause film processing problems. In an effort to solve this problem for high VA content ethylene copolymers, the inventors have surprisingly found that the addition of EBO improves film forming capability while minimizing negative effects on film properties such as clarity or other required physical parameters.
U.S. Pat. No. 4,510,281 describes the combination of EVA copolymers with certain oleamides to provide tack free pellets for industrial end uses. The oleamides and other esters described therein as additives improve the free-flowing properties of the pellets by incorporating into the polymer material prior to pelletization about 500-10,000 parts per million (ppm), especially 1000-5000 ppm, based on the polymer weight of an additive selected from the group consisting of N,N′-ethylenebisoleamide, N,N′-ethylenebiserucamide, N,N′-diolelyladipamide, and N,N′-dierucyladipamide. There is no specific teaching in this reference of the use of the compositions therein to produce a film or a film having processing advantages. There is, however, a general teaching relating to improvement of the handling and packaging throughput in actual production as a way to monitor good slip properties or antiblocking properties, especially for higher vinyl acetate content copolymers which could not be assessed by standard stick temperature tests. There is no requirement in the present invention that the additive be incorporated into the ethylene copolymer resin before pelletization.
Grades of ELVAX® containing, for example, N,N-ethylenebisoleamide have been sold by E. I. du Pont de Nemours and Company for industrial applications but have not been sold or used as packaging grade or film-forming resins. Grades of ELVAX® resins not containing an additive of this nature have been sold into the packaging market.
U.S. Pat. No. 4,956,232 discloses the use of slip additives in multilayer polypropylene films. Slip additives which may be used in making the films disclosed in the U.S. Pat. No. 4,956,232 patent are those which are incompatible with polypropylene, i.e., those which bloom to the surface from the core and skin layers. Non-ionic surfactants, such as the amides and carboxylic acids, were of particularly interest in this patent disclosure. Amides which were preferred included amides of carboxylic acids having at least five carbon atoms, for example, behenamide, linolenamide, arachidamide, ricinol-amide, palmitamide, myristamide, linoleamide, lauramide, capramide, perlargonamide, caprylamide, oleamide, steramide, N,N′-ethylene bisoleamide, and the most preferred slip additive, erucamide. Carboxylic acids which were also described as useful included those having at least four carbon atoms, for example, butyric, caproic, caprylic, capric, lauric, lauroleic, myristic, myristoleic, pentadecanoic, palmitic, palmitoleic, margaric, stearic, oleic, linoleic, linolenic, ricinoleic, 2,3-dihydroxystearic, 12-hydroxystearic, behenic, eleostearic, arachidic, 2-ecosenoic, 4-eicosadienoic, 2-docosenoic, 2-tetracosenoic, 2,4,6-tetracosatrienoic and the like.
The slip additive in the above patent disclosure was preferably dry blended together with the polypropylene resin of layer (B) or the heat-sealable resin of layer (A) and then melt mixed. Alternatively, the additive could be incorporated into a minor portion of the resin as a master batch to form a high concentration mix of the additive and the resin. This could then be diluted to the appropriate proportion by the addition of more resin. There is no teaching herein of the use of any of these additives with an EVA resin or film.
U.S. Pat. No. 4,517,242 discloses a combination of ethylene copolymer resins and lubricating agents such as ethylenebisoleamides in glass coating compositions.
U.S. Pat. No. 3,879,330 discloses food wrap consisting of a vinylidene chloride polymer and a thermoplastic urethane polymer. The food wrap films of the invention can contain conventional additives such as lubricating additives, anti-blocking agents, anti-cling agents, and the like, all of which are known in the art. To illustrate, the food wrap films of the invention typically contain up to about 3 weight percent diatomaceous earth as an anti-blocking agent and up to about 2 weight percent of ethylenebisoleamide as a slip agent.
U.S. Pat. No. 5,468,444, describes the production of oriented thermoplastic films by blown-film extrusion. U.S. Pat. No. 5,453,209 discloses chemical metal and oil treating compositions and processes related thereto. U.S. Pat. No. 4,394,473 discloses polybutadiene bags and films. U.S. Pat. No. 3,645,822 discloses a method for providing multilayer films having improved slip properties. U.S. Pat. No. 5,468,444 discloses film-forming thermoplastic resins containing lubricants selected from aliphatic alcohol fatty acid esters obtained from an aliphatic alcohol having 1 to 12 carbon atoms, and preferably 1 to 6 carbon atoms, and a fatty acid having 10 to 22 carbon atoms, and preferably 12 to 18 carbon atoms, such as glycerol monooleate, glycerol di- or trioleate, glycerol triricinoleate, glycerol acetylricinoleate, methyl acetylricinoleate, ethyl acetylricinoleate, butyl acetylricinoleate, propylene glycol oleate, propylene glycol laurate, pentaerythritol oleate, polyethylene glycol oleate, polypropylene glycol oleate, polyoxyethylene glycerol, polyoxypropylene glycerol, sorbitan oleate, sorbitan laurate, polyethylene glycol sorbitan oleate, and polyethylene glycol sorbitan laurate; polyalkylene ether polyols, such as polyethylene glycol and polypropylene glycol; sugar fatty acid esters, epoxidized soybean oil, polyoxyethylene alkylamine fatty acid esters, polyoxyethylene alkylphenyl ethers; higher fatty acid amides having 12 to 22 carbon atoms, such as oleamide, stearamide, and erucamide; ethylene-bis-stearamide, ethylene-bisoleamide, polyethylene wax, polypropylene wax, and liquid paraffin. Suitable nucleating agents include inorganic substances, such as talc and silica. Suitable tackifiers include castor oil derivatives, low-molecular viscous polybutylene, sorbitan higher fatty acid esters, terpene resins, and petroleum resin.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to a polymeric film forming composition comprising an ethylene copolymer selected from an ethylene copolymer and an olefinic bisoleamide selected from an oleamide which affects film-forming properties of high ester content ethylene copolymer resins which heretofore have not produced film with the requisite physical properties. The present invention relates to a film-forming composition consisting essentially of an ethylene copolymer having a percentage of vinyl acetate monomer incorporated at 10% wt or higher relative to the ethylene, and an olefinic bisoleamide of the formula described herein wherein the oleamide additive is
Hoh George L. K.
Shekhar Alok
Vogel Randall Allen
Dobson Kevin S.
E. I. du Pont de Nemours & Co.
Tarazano D. Lawrence
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