| Novel foams and coatings from low crystallinity vinylidene fluoride hexafluoropropylene copolymers -> Monitor Keywords |
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  Novel foams and coatings from low crystallinity vinylidene fluoride hexafluoropropylene copolymersUSPTO Application #: 20060210715Title: Novel foams and coatings from low crystallinity vinylidene fluoride hexafluoropropylene copolymers Abstract: Processes for the preparation of adherent polyvinylidene fluoride, hexafluoropropylene coatings on objects of glass, metal, stone, bricks, cementitious objects, mortar, title and the like without the need of primers or alloying polymers and open celled foams from polymers having a Tg below the freezing point of the aqueous phase of the latex (either emulsion or suspension) of their formation are disclosed. (end of abstract)
Agent: Arkema Inc. Patent Department - 26th Floor - Philadelphia, PA, US Inventors: Ramin Amin-Sanayei, Lawrence K. Wempe, Kurt Arthur Wood, Stefano Finocchiaro, Delphine Tillier USPTO Applicaton #: 20060210715 - Class: 427372200 (USPTO) Related Patent Categories: Coating Processes, With Post-treatment Of Coating Or Coating Material, Heating Or Drying (e.g., Polymerizing, Vulcanizing, Curing, Etc.) The Patent Description & Claims data below is from USPTO Patent Application 20060210715. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application claims priority from provisional application 60/268,843 filed Feb. 15, 2001. BACKGROUND OF THE INVENTION [0002] This invention relates to compositions of matter classified in the art of chemistry as fluoropolymers, more specifically to copolymers of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) and still more specifically to such copolymers having very low or no crystallinity, to processes for their use and the products produced by such use processes. The copolymers at all levels of HFP content remain highly flexible, thermoplastic copolymers which show low surface tack even at high HFP levels and thereby permit use of such copolymers in unique applications for which polyvinylidene fluoride homo- and copolymers previously known were not considered suitable, or were considered suitable only when combined with other polymers or other materials such as primers and the like. [0003] Fluoropolymers and copolymers of VDF, collectively VDF-based polymers wherein the VDF portion is greater than the total molecular percent of comonomers, are well known and widely used. Among the variety of fluoropolymers based upon tetrafluoroethylene, chlorotrifluoroethylene, and other specialty fluorine-containing monomers, the VDF polymers are unique offering the widest possible range of processing options to obtain articles having the beneficial attributes associated with improved chemical resistance and surface properties associated with the high concentration of carbon fluorine bonds. Thus, among the wide spectrum of fluoropolymers, the VDF polymers may be melted in typical processing equipment for thermoplastic resin for extrusion or molding or combinations such as extrusion-blown film and molding tanks. [0004] This versatility in processing options is related to the linear polymer chain structure and the presence of the highly polar-CF.sub.2-groups alternating along the VDF polymer chain. The microstructure of the polymer chain and morphology of these polymers reflects these two factors in many interesting ways as described in Polymeric Materials Encyclopedia, 1996, Vol. II, CRC Press; Vinylidene Fluoride-Based Thermoplastics (Overview and Commercial Aspects), J. S. Humphrey, pp. 8585 to 8588; Vinylidene Fluoride-Based Thermoplastics (applications), J. S. Humphrey and E. J. Bartoszek, pp. 8588-8591; Vinylidene Fluoride-Based Thermoplastics (Blends with Other Polymers), J. S. Humphrey and X. Drujon, pp. 8591-8593; Vinylidene Fluoride-Based Thermoplastics (Homopolymerization and Copolymerization), J. S. Humphrey and X. Drujon, pp. 8593-8596. [0005] Low crystallinity fluorinated polymers are highly useful, particularly as coating and encapsulants, because of their low surface energy, low refractive index, good chemical resistance, and the relative ease of coating or encapsulating objects with such inert polymers. The balance between amorphous and crystalline regions, the nature and extent of the crystalline regions, and the interphase between these regions affects the processability options to obtain articles having the beneficial attributes and hence, the ultimate applications for a given resin composition. [0006] Copolymers of VDF and HFP vary in their properties. At one end of the spectrum there are totally amorphous thermoplastic polymers and at the other extreme the highly crystalline polymers. The microstructure of the polymer chain determines the flexibility (or alternately the stiffness) at a given temperature. This mechanical behavior is controlled by the type and amount of the crystalline phase (if any) and the dynamics of the molecular motion along the chain such that at some temperature the polymer undergoes a second order change in response to applied stresses, the so-called glass transition temperature (Tg). Above the Tg the polymer chain has molecular motions which are free to rotate, stretch, etc. and thereby absorb the energy input. Below the Tg the molecular motions are frozen and the stresses may lead to brittle fracture or glass-like behavior. [0007] The immediate invention is concerned more with the morphology and crystalline/amorphous ratio of the VDF polymers and the ultimate end uses. It is therefore important to understand the background of the present invention in the context of the teaching how crystalline and amorphous content fit into the range of polymers which are classed as thermoplastic engineering resins or thermoplastic elastomeric resins. In this particular invention, the key attribute is related to highly flexible resins related to both categories. This invention employs a variety of VDF-HFP resins, which are to the low level of crystallinity compared to resins of the otherwise same nominal monomer ratio composition produced by standard teachings. Thus, the present invention relates to a novel fluoro-thermoplastic having a unique combination of properties including excellent flexibility, low temperature processability, high clarity, solution stability and room temperature film forming capability from aqueous dispersion and which, as stated above, enables them to be used in unique ways. PRIOR ART [0008] U.S. Pat. No. 3,051,677 describes batch emulsion and continuous emulsion processes for copolymerization of vinylidene fluoride and hexafluoropropylene (HFP) in the range of 30 to 70 weight percent of hexafluoropropylene monomer and 70 to 30 weight percent vinylidene fluoride monomer. The copolymers described in this reference have relatively high crystallinity as is confirmed by the properties described in the document for the products exemplified. Analogous materials from a batch process are described by Moggi, et al., in Polymer Bulletin, Vol. 7 pp. 115-122 (1982). [0009] U.S. Pat. No. 3,178,399 describes both batch and semi-continuous emulsion processes for preparing HFP-VDF copolymers having between 85 and 99 mole percent VDF and 1 and 15 mole percent HFP (approximately 2 to 30 weight percent HFP and 70 to 98 weight percent VDF). Once again, the copolymers produced having relatively high internal crystallinity and this fact is evidenced by the physical data provided for those copolymers actually exemplified. This patent discloses that Tensile X Reversible Elongation was increased as the overall HFP proportion decreased in the copolymer. This implies that crystallinity increases as HFP content decreases. [0010] U.S. Pat. No. 5,093,427 describes HFP-VDF copolymers, with the other extreme crystalline melting behavior, containing from about 1 to 20 weight percent HFP wherein, based on the synthetic method described, a polymer containing significant portions having a high proportion of HFP in the copolymer results. Thus, compositions of the copolymers described in this reference are intended to be highly crystalline which in turn are significantly different from the copolymers contemplated by the present invention. [0011] Indonesian Patent Application W-980105, published Nov. 26, 1998 as number 020.295A equivalent to WO 98/38242 and to U.S. patent application Ser. No. 09/031,014, the contents of which have been included in CIP application Ser. No. 09/641,015 discloses an emulsion process for producing HFP-VDF copolymers having more homogenous distribution of the comonomers from to chain than polymers of the prior art thereby having reduced extractable content and improved solution clarity over HFP-VDF copolymers prepared according to the techniques of the preceding references. These materials differ from the copolymers of the present invention because the products of the present invention have crystallinity level well below of those of corresponding polymers of W-9809105. [0012] In Polymer, Vol. 27, pp. 905 (1986) and Vol. 28, pp. 224 (1987), Moggi, et al., report synthesis of HFP-VDF copolymers and studies of various physical properties and how these may be correlated to certain internal structural features such as crystallinity, monomer sequencing in individual molecules and the like. The limited synthesis information indicates that the polymers formed were analogous to those prepared according to the previous references except for U.S. patent application Ser. No. 09/031,014 and the limited physical data provided is consistent with this interpretation and that the polymers described had a high degree of crystallinity. [0013] Although it is well established in the prior art to reduce crystallinity by means of adding higher amounts of HFP to the copolymer, there is no prior art suggesting how to produce as low crystallinity as is provided by the present invention at any given nominal proportion of HFP. Thus, the copolymers employed herein have measurably lower crystallinity at any given HFP level than copolymers with the same nominal HFP content produced in accordance with processes enabled by any of the above listed references and, thus have use properties completely unpredictable from the properties of previously known VDF/HFP copolymers. [0014] U.S. Pat. No. 4,618,641 discloses treatment of fabric with concentrated dispersions of vinylidene fluoride copolymers stabilized with nonhalogenated carboxylic acid surfactants. High solids concentrations are required and the fabric treatments must be heat set. The present invention using the copolymers described herein are able to accomplish the same or better treatment results using lower solids concentrations, while avoiding the need for a specific class of detergents. [0015] U.S. Pat. Nos. 4,983,459 and 4,997,684 disclose methods of treatment and the dirt, stain repellant and non wetting surfaced articles treated with a mixture of a perfluoroalkyl silane and a fluorinated olefin telomer. The surfaces treated are stated to be glass compositions, or other inorganic surfaces such as ceramics, enamels, metal or metal oxide films. The formula given for the fluorinated telomer excludes the copolymer of this invention and the present invention provides an adherent coating on glass, metal and other mineral, ceramic and the like surfaces without the need of any silane additive primer coat. [0016] Chem. Abstracts: CAN 70:79210, abstracting Mekh. Polim (1968) 4(6), 1065-70 summarizes the effect on the adhesive properties due to treatment of a film of semicrystalline VDF/HFP copolymers on steel, and window glass. The steel and glass coated with the film were subjected to treatment at 200 to 280.degree. for 1 to 120 minutes. Treatment of the film coated steel at 280.degree. C. for 2 hours greatly improved adhesion of the film and resistance to boiling water due to formation of Fe.sub.2O.sub.3 under the coating. HCl and HNO.sub.3 introduced at the interface between the film and either glass or steel reduced adhesion. While the abstract concludes that adhesion is possible at temperatures below the melting point of the film no actual values are provided. Given the fact that later literature indicates that satisfactory adhesion of VDF homo-and copolymers including these with HFP known prior to the copolymer used in the present application required alloying with nonfluoropolymers at least the use of primer coats for satisfactory adhesion to substrates such as glass and steel, this abstract provides no information which would lead one having knowledge in the art to discover the unique use properties applicants have found for the VDF/HFP copolymers described and used herein. [0017] U.S. Pat. No. 4,347,268 discloses coatings made from metallic oxide free solvent solutions of elastomeric copolymers of HFP and VDF in the VDF/HFP concentration ranges of U.S. Pat. No. 3,051,677 and a vinyl copolymer by applying the solution to a surface and evaporating the solvent. Suitable substances for coating are stated to be aluminum, steel, glass, EPDM and nitrile rubber. [0018] U.S. Pat. No. 4,764,431, corresponding to EP 0192 494 B1 discloses the use of solvent solutions of copolymers of VDF and HFP in the VDF/HFP concentration ranges of U.S. Pat. No. 3,051,677 for applying coatings for protecting and consolidating stone materials. [0019] EP 0481 283 B1 corresponding to U.S. Pat. Nos. 5,219,661 and 5,270,115 discloses solvent based reversible polymer gels for treating and consolidating stone materials and impregnating various fabrics including glass cloth. One essential material is an elastomeric VDF/HFP copolymer in the VDF/HFP concentration ranges of U.S. Pat. No. 3,051,677 and a second essential component is a polymer selected from non elastomeric vinylidene fluoride polymer or copolymer, a vinyl fluoride polymer or a (meth)acrylate polymer or copolymer. [0020] U.S. Pat. No. 4,141,873 describes an aqueous based vinylidene fluoride polymer film forming suspension for coating various substrates which also contains a suspension of a (meth)acrylate polymer and a water dispersible latent solvent for the two polymers. [0021] U.S. Pat. No. 4,985,282 corresponding to EP 0374 803 B1 discloses the protection of surfaces of stony materials, tiles, cement conglomerates and relevant manufactured articles by applying a mixture of an aqueous dispersion of a VDF/HFP elastomer in the VDF/HFP concentration ranges of U.S. Pat. No. 3,051,677 and an aqueous emulsion or microemulsion of a perfluoropolyether by conventional methods to such surfaces. [0022] U.S. Pat. No. 5,212,016 corresponding to EP 0479 240 B1 describes consolidating of and protection of surfaces of stone, marble, sandstone, bricks concrete and articles manufactured therefrom by applying solvent solution of an mixture of a then known nonelastomeric polyvinylidene fluoride homo- or copolymer or a polyalkyl methacrylate and an elastomeric copolymer of VDF and HFP in the VDF/HFP concentration range of U.S. Pat. No. 3,051,677. Continue reading... Full patent description for Novel foams and coatings from low crystallinity vinylidene fluoride hexafluoropropylene copolymers Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Novel foams and coatings from low crystallinity vinylidene fluoride hexafluoropropylene copolymers patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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