MX2015003521A - Chlorofluoropolymer coated substrates and methods for producing the same. - Google Patents

Abstract

A coated substrate is described, which includes a substrate comprising a cellulosic fiber material and a copolymer coated with a thin film on at least one surface of the substrate. The copolymer has at least two comonomer units of the formula: CX2CYA, wherein each X is independently selected from the group consisting of H, C1 and F; Y is selected from the group consisting of H, C1, F, O (CZ2) nCZ3, (CZ2) nCZ3, (OCZ2CZ2) nCZ3 and (O (CZ2) n) nCZ3, in which each n is independently from approximately 1 to approximately 12 and each Z is independently selected from the group consisting of H, C1 and F; and A is selected from the group consisting of H, C1 and F; provided that at least one comonomer unit, at least one of A, Y, and, or X or any Z is C1.

Description

SUBSTRATES COATED WITH CHLOROFLUOROPOLYMERS AND METHODS TO PRODUCE THEMSELVES CROSS REFERENCE TO RELATED REQUESTS The present disclosure claims the benefit of priority to the US provisional patent application.

Serial No. 61 / 704,956, filed on September 24, 2012, whose content is incorporated here as a reference in its entirety.

FIELD OF DESCRIPTION The present disclosure relates to aqueous chlorofluoropolymer dispersions used in substrate coating applications. In particular, the present disclosure relates to aqueous dispersions of chlorofluoropolymer applied to cellulosic fiber substrates.

BACKGROUND The use of paper-based products as packaging material to pack, for example, food, alcoholic beverages, perfumes and cosmetics, medical products and tobacco, among others, is growing due to its biodegradability and sustainability. Paper products, however, lack sealing properties chemical thermal, solvent, oil and resistance to stains, moisture and aroma barrier, and, although the lamination of paper products with PVC imparts thermal barrier sealing properties to paper, they have no resistance to chemicals, solvents, oil and spots As such, it would be desirable to provide an improved coating for, and methods for, the coating of paper-based products that impart resistance to chemicals, solvents, oil and stains for paper-based products, as well as barrier properties and sealing capability. thermal while maintaining its biodegradability. In addition, other features and characteristics of the subject matter of the invention desirable will be evident from the detailed description later of the subject matter of the invention and the appended claims, taken together with this background of the subject matter of the invention.

BRIEF SUMMARY In an illustrative embodiment, a coated substrate is described, which includes a substrate that includes a cellulosic fiber material and a copolymer coated with a thin film on at least one surface of the substrate. The copolymer has at least two comonomer units of the formula: CX2CYA, wherein C is carbon and wherein each X is independently selects from the group consisting of H, C1 and F; Y is selected from the group consisting of H, Cl, F, 0 (CZ2) nCZ3, (CZ2) nCZ3, (OCZ2CZ2) nCZ3 and (O (CZ2) n) nCZ3, wherein each n is independently from about 1 to about 12 and each Z is independently selected from the group consisting of H, Cl and F; and D is selected from the group consisting of H, Cl and F; provided that at least one comonomer unit, at least one of A, Y, and, or X or any Z is Cl.

In another illustrative embodiment, a method for coating a substrate is described, which includes the step of contacting at least one surface of a substrate including a cellulosic fiber material with an aqueous dispersion of a copolymer. The copolymer has at least two comonomer units of the formula: CX2CYA, wherein each X is independently selected from the group consisting of H, Cl and F; Y is selected from the group consisting of H, Cl, F, 0 (CZ2) nCZ3, (CZ2) nCZ3, (OCZ2CZ2) nCZ3 and (O (CZ2) n) nCZ3, wherein each n is independently from about 1 to about 12 and each Z is independently selected from the group consisting of H, Cl and F; and A is selected from the group consisting of H, Cl and F; provided that at least one comonomer unit, at least one of A, Y, y, or X or any Z is Cl.

This brief summary is provided to introduce a selection of concepts in a simplified form that is described later in the detailed description. This summary is not intended to identify the key characteristics or essential characteristics of the subject matter claimed, nor is it intended to be used as an aid in determining the scope of the subject matter claimed.

DETAILED DESCRIPTION The embodiments of the present disclosure are broadly directed to the application of chlorofluoro-olefin / fluoro-olefin copolymers to cellulosic fiber substrates. In one embodiment, cellulosic fiber substrates may include what is hereinafter referred to as "paper" or "paper products." As used herein, the terms "of paper" and "paper products" are intended to refer broadly and inclusively to the class of substrates that are derived from cellulosic fiber pulp and are provided in the form of dried leaves, paper or fibreboard cellulose An illustrative method for the production of "paper" or "paper products" as used herein is set forth briefly below, by way of a non-limiting example. In addition to the pulp fibers derived from wood products, coatings according to the present description can be applied to the own wood product (that is, a hardwood product that has not been transformed into pulp). As such, while some embodiment examples described in this document are directed to paper and paper based products, it will be understood that wood products serve as suitable substrates for the application coatings described herein as well.

The cellulose pulp is generally described in relation to cellulose fibers derived from wood pulp. However, the modalities described herein may be used in conjunction with any cellulosic fiber derived from any source. Illustrative cellulosic fibers include, but are not limited to, those derived from wood, such as wood pulp, as well as nonwoven cotton, straw and grass fibers, such as rice and esparto, from reeds and rushes, such as bagasse, bamboo, fibrous stems, such as jute, flax, kenaf, hemp, flax and ramie, and from the fibers of leaves, such as abaca and sisal. It is also possible to use mixtures of one or more cellulosic fibers.

Wood fibers suitable for use in the described embodiments can be derived from either a source of softwood pulp or source of hardwood pulp or mixtures thereof. Exemplary soft pulp sources include trees such as several pines (pine Slash, taeda pine, white pine, Caribbean pine), western hemlock, several spruces, (for example, Sitka spruce), Douglas fir and / or mixtures thereof. Exemplary wood pulp sources include trees such as sweet gum, black gum, maple, oak, eucalyptus, poplar, beech, and poplar or mixtures thereof.

As used herein, the term "pulp" refers simply to a mass or agglomeration of cellulose fibers. The pulp can be supplied in a dry form or as a suspension. As used herein, the term "fiber" or "fibrous" is understood to refer to a particulate material in which the length to diameter ratio of said particulate material is greater than about 10. In some embodiments, the cellulosic fibers they are characterized by an average length, for example, a WAFL length, between about 0.1 to 6 mm. In other embodiments, the average length of the fibers is between about 0.8 and 4 mm.

The cellulose pulp is produced using a primary pulp manufacturing process as is known in the art. Wood pulp manufacturing operations, by way of a general example, involve a series of steps, such as digestion, loosening and the like, which separate the pulp into individual fibers and eliminate impurities from the pulp. A wood pulp manufacturing operation by way of example is the Kraft pulp manufacturing process, as is known in the art. However, chemical pulp manufacturing operations, such as, but not limited to, sulfite pulp manufacturing operations, and organic solvent pulp manufacturing operations, may also be used.

As noted above, the use of paper-based products as packaging material to pack, for example, food, alcoholic beverages, perfumes and cosmetics, medical products and tobacco, among others, is growing due to its biodegradability and sustainability. Paper products, however, lack chemistry, resistance to solvents and oil, moisture and aroma barrier, and thermal sealing properties. Although lamination of paper products with PVC imparts barrier properties and thermal sealing capability to paper, they have no resistance to chemicals and solvents.

In order to overcome the difficulties mentioned in the use of paper-based products, it has unexpectedly been discovered by the inventors herein that the chlorofluoro olefin / fluoro-olefin copolymers impart desirable chemicals, and resistance to solvents and oil When applied to paper-based products, In addition to moisture barrier properties and capacity of thermal sealing that were previously known with respect to PVC coatings.

As used herein, chlorofluoro-olefin / fluoro-olefin is found, they have many inherent advantages. The chlorofluoro-olefin / fluoro-olefin are resistant to abrasion and when conformed into a film it has > 90% transmission of sunlight. The chlorofluoro-olefins / fluoro-olefin copolymers have many advantages that make more than PTFE, polytetrafluoroethylene-hexafluoropropylene copolymers (FEP) and polytetraf-lorooroethylene-hexafluoropropylene-vinylidene fluoride (THV, manufactured by Dyneon) terpolymers. The chlorofluoro-olefins / fluoro-olefins copolymers can be processed at moderate, ambient temperatures and can be easily coated by successive coatings of aqueous dispersions of chlorofluoro-olefin / fluoro-olefin copolymers. Because the chlorofluoro-olefins / fluoro-olefins copolymers have a relatively high surface tension, the coating with successive passes of these copolymers can be achieved with very low levels of wetting agents, of 0.1-2% by weight being typical depending on if the wetting agent additive is fluorinated, perfluorinated, or non-fluorinated, or any mixture thereof. The chlorofluoro-olefin / fluoro-olefin copolymers are excellent film formers that facilitate the production of the cast film dispersion for lamination on the cloth, or the direct coating / coating of the cloth to a desired thickness with low levels of wetting agents. In addition, the chlorofluoro-olefin / fluoro-olefin coatings resist solvents, acids, oils, stains, abrasion and UV rays and many other environmental impacts.

Certain chlorofluoro-olefin / fluoro-olefin copolymers are disclosed by McCarthy et al., Proceedings of the Twenty-Fifth International Water-Borne, High Solids & Powder Coatings Symposium 541 Feb.18-20, (1998) and Bringer, Encyclopedia of Polymer Science and Technology (ed., Vol.7, Interscience Publishers, New York, 1967) p. 204, by International Patent Publication Nos. WO 97/11979 and WO 97/17381, and by U.S. Pat. No. 6,759,131. Still further, chlorofluoro-olefin / fluoro-olefin copolymers and methods for manufacturing thereof are known in the art.

As noted above, the chlorofluoro-olefin copolymers are capable of forming aqueous olefin-chlorofluoro copolymer dispersions, and as such are particularly suitable for use in the application thereof to paper and paper products such as paper products and Paper can simply be submerged in the dispersion for a period of time, and then dried. In particular, the dispersions of chlorofluoro- copolymer Water-based products can be prepared from ultra high molecular weight chlorofluoro-olefin copolymers which could not otherwise be formed by melt extrusion. When the emulsion particles collide, it is only necessary to entangle the chain ends between the polymer particles, not a melt flow volume. For aqueous dispersions of discrete submicron sized particles, the minimum film forming temperature is the main factor determining film formation. The coalescence is independent of the melt viscosity of the polymer and the molecular weight of the polymer.

Without being bound by any particular theory, it is believed that the high molecular weight of the chlorofluoro-olefin copolymers restricts UV-induced crystallization and limits the mobility of the polymer chain and otherwise causes the formation of large and brittle spherulites, and any other morphological changes. It is also believed that high molecular weight decreases the tendency of the copolymer to move or deform permanently under the influence of stresses. Other benefits of the high molecular weight of the polymer include improved solvent resistance and increased toughness. In particular, the copolymers have a tensile strength and upper modulus and are more resistant to abrasion.

All the materials used to make the chlorofluoro-olefin copolymers of the present disclosure are commercially available. For example, CTFE is available from Honcywell International Inc. of Morristown, NJ, VDF is available from Solvay SA of Brussels, Belgium, and the vinyl esters are from The Dow Chemical Company of Midland, MI. At least one comonomer from which the copolymer composition is prepared is a chlorofluoro-olefin. Suitable chlorofluoro-olefins include polychlorinated fluoroolefins such as CTFE, fluorotrichloroethylene, 1,1-dichlorodifluoroethylene, cis and trans isomers of 1,2-dichlorodifluoroethylene, 1-chloro-1-fluoroethylene, and perchlorofluoroethers, perchlorofluorodioxoles.

The copolymer compositions can be prepared from up to three different chlorofluoro-olefin comonomers. Alternatively, one or two chlorofluoro-olefin comonomers can be copolymerized with one or two fluoro-olefins. Suitable fluorinated diene comonomers from which the copolymer compositions can be prepared have the formula CX2CYA, wherein X, Y and A each do not include CI but are somehow as defined above. Preferred fluorinated olefin comonomers include dfines and partially perfluorinated such as VDF, TFE, HFP, vinyl fluoride and 1,2-difluoroethylene, fluorinated alpha-olefins such as 3,3,4,4,4-penta-fluoro-1-butene, perfluoroethers such as perfluoro (propylvinyl ether) and perfluoro-dioxoles such as perfluoro (1,3-dioxole) and perfluoro (2,2-dimethyl-l) , 3-dioxol).

The exemplary copolymers contain predominantly chlorotrifluoroethylene, and at least one fluoro-olefin selected from the group: VDF, hexafluoropropylene, tetrafluoroethylene, vinyl fluoride, trifluoroethylene, and fluorinated or perfluorinated alkyl vinyl ethers such as perfluoropropy1vinyl ether. In another illustrative embodiment, the comonomers used to form the copolymer composition are selected from CTFE, VDF and a fluorinated vinyl ester. For example, the comonomers may have the formula CX2CYA, wherein X, Y and A are as defined above, to the exclusion of olefins in which each X and A are hydrogen, provided that at least one comonomer unit contains a chlorine atom. In a preferred embodiment by way of example, the comonomers used to form the copolymer composition are CTFE and VDF.

The copolymer compositions may optionally include a chloro-olefin comonomer. Essentially, any chloro-olefin can be employed, and among the suitable chloro-olefins are vinylidene chloride, vinyl chloride and trichlorethylene.

The copolymer compositions may also optionally include a non-halogenated vinyl ester or an acid as a comonomer in addition to the halogenated olefins, provided that at least two halogenated olefin comonomers are employed. The vinyl ester is preferably a vinyl alkyl ester, wherein the alkyl group contains from about 1 to about 12 carbon atoms. The acid comonomers include acrylic acid, methacrylic acid, methyl methacrylate and other alkyl acrylates. Both vinyl ester and acid comonomers are commercially available from, for example, The Dow Chemical Company of Midland, MI.

Preferred vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl hexanoate, vinyl stearate, ethenyl ester neononanoate, n-valeric vinyl esters, caproic acid, Tauric, versatic, isovaleric , 2-ethyl hexanoic, 2, 2-dimethyl-octanoic, 2-methyl-2-propyl-pentanoic and 4-methyl-4-butyl hexanoic, as well as neoacids of vinyl esters. Preferred acids include acrylic and methacrylic acids.

The copolymerization of vinyl esters with fluoro-olefins is known in the art. U.S. Patent Nos. 3,451,978; 3,531,441; 3,318,850 and 3,449,305 describe the copolymerization of either fluoride of vinyl (VF) or VDF with some amount of a vinyl ester.

In each of these embodiments, the main component is VF or VDF, another component is TFE, and a third component that includes a vinyl ester. The descriptions of the four patents are incorporated herein by reference.

As for the vinylester that can be incorporated into the polymer, vinyl propionate and vinyl butyrate serve as non-limiting examples as suitable. Vinyl propionate is an olefin partially soluble in water that accelerates the emulsion polymerization of chlorofluoro-olefins and fluoro-olefins. Due to the slightly branched nature of vinyl propionate, it also retards crystallization and the formation of large spherulites, while not preventing their formation. Non-halogenated olefins such as ethylene or propylene can also be incorporated into the polymer.

The amount of each monomer unit used to prepare the copolymer will depend primarily on the application in which the material will be used (for example, an application of room temperature generally requires a composition with a glass transition temperature close to room temperature). In the case of chlorofluoro-olefins, in general, the increase in comonomer levels leads to a decrease in the glass transition temperature. A technical expert can easily optimize and without undue experimentation of these ranges to obtain an essentially amorphous chlorofluoropolymer composition having the desired properties.

Examples of polymers contain less than about 90% by weight of a chlorofluoro-olefin, up to about 30% by weight of a fluoro-olefin, and from about 0 to about 10% by weight of a vinyl ester and / or an olefin not fluorinated When the comonomers used to form the copolymer composition are CTFE and VDF, the CTFE is present in an amount of about 70 to about 95% by weight, for example about 75 to about 94% by weight, and such as about 80 to about 90% by weight. When the comonomers used to prepare the copolymer composition are CTFE, VDF and a vinyl ester, the vinyl ester is present in an amount of from about 0.1 to about 5% by weight, for example from about 0.5 to about 3% by weight , the VDF component is present in an amount of from about 5 to about 25% by weight, for example from about 10 to about 25% by weight, and the CTFE component is present in an amount of less than about 88% by weight , for example less than about 85% by weight.

The copolymers of the invention have a crystallinity index of from 0 to about 10%. The most preferred they are polymers that have a crystallinity index of no more than 5%. For copolymer compositions consisting of an aqueous dispersion of 0.05 to 0.5 microns of spherical emulsion particles, the weight average molecular weights between about 2,000,000 and about 20,000,000 Daltons are suitable. Weight average molecular weights of less than 10,000,000 Daltons are typical, with a weight average molecular weight of approximately 8,000,000 Daltons being particularly suitable.

Copolymers suitable for use in accordance with the present disclosure are polymerized by conventional free radical polymerization methods. Any initiator of commercially available radicals can be used in accordance with the modalities described herein. Suitable candidates include thermal and oxidation-reduction initiators or "redox" initiator systems. Thermal initiators include: metal persulfates such as potassium persulfate and ammonium persulfate; organic peroxides or hydroperoxides, such as diacyl peroxides, ketone peroxides, peroxyesters, dialkyl peroxides and peroxyketals; azo initiators such as 2,2'-azobisisobutyronitrile and water-soluble analogues thereof; and mixtures of any of the foregoing.

Any redox initiator system known to be useful in the preparation of fluorinated polymers such as PCTFE can be used in the present invention. Exemplary redox initiator systems include: 1) an oxidizing agent or organic or inorganic mixtures thereof; and 2) an organic or inorganic reducing agent or mixtures thereof. Suitable oxidizing agents include metal persulfates such as potassium persulfate and ammonium persulfate; peroxides such as hydrogen peroxide, potassium peroxide, ammonium peroxide, tertiary butyl hydroperoxide ("TBHP") ((CH3) 3COOH), eumenohydroperoxide, and t-amylhydroperoxide; manganese triacetate; potassium permanganate; ascorbic acid and mixtures thereof. Suitable reducing agents include sodium sulfites such as sodium bisulfite, sodium sulfite, sodium pyrosulfite, sodium-m-bisulfite ("MBS") (Na2S20s) and sodium thiosulfate; other sulfites such as ammonium bisulfite; hydroxylamine; hydrazine; ferrous irons; organic acids such as oxalic acid, malonic acid, citric acid and mixtures thereof.

A suitable free radical initiator system is one that serves to simultaneously emulsify the polymer while initiating the polymerization, thus eliminating the need for large amounts of surfactants. Redox initiator systems are suitable for this purpose. Exemplary redox initiator systems utilize an MBS reducing agent and an HPBT oxidizing agent. By For example, the redox initiator system is used in conjunction with a transition metal accelerator. Accelerators can greatly reduce the polymerization time. Any commercially available transition metal can be used as an accelerator in the invention. Exemplary transition metals include copper, silver, titanium, ferrous iron and mixtures thereof.

The amount of radical initiator used in the process depends on the relative ease with which the various monomers co-polymerize, the molecular weight of the polymer and the desired reaction rate. Generally, from about 10 to about 100,000 ppm of initiator, for example from about 100 to about 10,000 ppm, can be used.

Optionally, in order to further accelerate the polymerization, the redox initiator system may include additional peroxide-based compounds. The amount of additional peroxide-based compound used ranges from about 10 to about 10,000 ppm, for example from about 100 to about 5000 ppm.

The radical initiator may be added before, simultaneously with and / or shortly after the addition and / or consumption of the monomers used to prepare the copolymer. When an additional compound based on peroxide is used it can be added in the same range specified for the primary radical initiator.

The chloro fluoro polymer compositions of the present disclosure can be made by a two step polymerization reaction. In one example, the monomers, water, and an initial charge of radical initiator are introduced into the appropriate polymerization vessel. The additional monomer is added throughout the reaction at a rate equal to the consumption rate to maintain a constant pressure. Incremental incremental charges of initiator are introduced into the vessel for the duration of the reaction to maintain the polymerization. The reaction mixture is maintained at a controlled temperature, while all reagents are loaded into the vessel and during the polymerization reaction.

The only requirement for the reaction vessel used to prepare the composition described herein is that it is capable of being pressurized and agitated. Conventional commercial autoclaves that can be sealed and pressurized at the required reaction pressures (preferably in excess of 3.36 MPa (500 psig)) are preferred. Horizontally inclined autoclaves are preferred to vertically inclined autoclaves, although both geometries can be used.

The aqueous medium in which the polymerization is carried out is water purged with deionized nitrogen. Generally, an amount equivalent to about half the capacity of the container, such as an autoclave, is used. The ratio of polymer to water is chosen in such a way as to obtain a dispersion of about 20 to about 60% polymer solids in water. The water is pre-charged in the autoclave. The process is an emulsion polymerization process free of surfactant that does not require a separate post-concentration stage to obtain high levels of emulsified polymer in water.

The monomers can be charged to the reactor vessel either in a semicontinuous or continuous manner during the course of the polymerization. "Semi-continuous", as used herein, means that a number of the batches of the monomers are charged to the reactor during the course of the polymerization reaction. The batch size is determined by the desired operating pressure. The molar ratio of total monomer consumed to radical initiator will depend on the particle size and the desired molecular weight. In one embodiment, the total molar ratio of monomer to initiator would be from about 10 to about 10,000, for example from about 50 to about 1000, and such as from about 100 to about 500 moles of total monomer of one mole of initiator.

The radical initiator is generally added gradually during the course of the reaction. For the purposes of this description, "initial charge" or "initial charge" of initiator refers to a rapid, large, individual or incremental addition of the initiator to effect the commencement of the polymerization. At the initial charge, generally between about 10 pp / min to about 1000 ppm / min is added over a period of about 3 to about 30 minutes, either before, after or during the charging of the monomers. As used further herein, "continuous charging" or "continuous charging" means the small, incremental, incremental addition of the initiator over a period of about 1 hour to about 6 hours, or until the polymerization is complete. In the continuous charge, generally between about 0.1 ppm / min to about 30 ppm add / min of initiator.

During the initiation of the polymerization reaction, the sealed reactor and its contents are maintained at the desired reaction temperature, or alternatively to a variable temperature profile which varies the temperature during the course of the reaction. The control of the reaction temperature is a factor for determine the final molecular weight of the chlorofluoropolymers produced. As a general rule, the polymerization temperature is inversely proportional to the product of the molecular weight. Typically, the reaction temperature should range from about 0 ° C to about 120 ° C, although temperatures above and below these values are also contemplated. The reaction pressure is between about 172 kPa to about 5.5 MPa, and for example about 345 kPa to about 4.2 MPa. High pressures and temperatures will produce higher reaction rates.

The polymerization is carried out with stirring to ensure adequate mixing. An adjustment of the stirring speed during polymerization may be desirable to avoid premature coagulation of the particles. Although the agitation rate and reaction time will typically depend on the amount of chlorofluoropolymer product desired, an expert in the art can easily optimize the reaction conditions without undue experimentation to obtain the claimed results. The agitation speed will generally be in the range of about 5 to about 800 rpm and, for example, from about 25 to about 700 rpm, depending on the agitator geometry and the size of the vessel. The reaction time will generally vary from about 1 to about 24 hours, for example from about 1 to about 8 hours.

Chlorofluoropolymers produced using the above free surfactant process are self-emulsifiable chlorofluorinated macromolecules having inorganic, functional "surfactant" end groups that impart excellent latex stability to the polymer when present in very low concentration. The chlorofluoropolymers produced in this way are dispersed in the aqueous medium by the binding of these inorganic fragments at the end of the polymer repeating units, thus creating a surfactant having both a hydrophobic component and a hydrophilic component. This binding leads to micelle formation, or, if the concentration of functionalized terminal groups is high enough, for complete dissolution in the water.

The type of "surfactant-like" end groups produced depends on the type of initiator system selected and the optional addition of compounds that can be incorporated into the polymer through chain transfer reactions. Examples of functional end groups such emulsifiers include, but are not limited to, sulfonates, carboxylates, phosphonates, phosphates and salts and acids thereof, ammonium salts and any mixture thereof.

The presence of sulfonic acid end groups has been found to affect more significantly the emulsification of chlorofluoropolymers in water. The amount of these functional end groups in the dispersion can be determined by first purification of the dispersion by methods known in the art, such as by ion exchange or dialysis, by titrating the dispersion with any known base, such as aqueous sodium hydroxide or hydroxide. of ammonium, and then expressing the amount in terms of molar equivalents of the base valued. The amount of these terminal functional groups expressed in moles of NaOH equivalent may range from about 0.0001 to about 0.5 moles of functional terminal groups per liter of chlorofluoropolymer dispersion obtained. The molar ratio of these functional end groups per fluoropolymer produced can vary from about 1: 10 to 10,000, for example from about 1: 10 to 1,000, such as from about 1: 50 to 500. An exemplary chlorofluoropolymer dispersion within the scope of this Description contains about 0.01 molar equivalents / kg of dry polymer.

In the absence of added surfactant, the particle size distribution of the dispersion produced according to the process of the invention resulting will be monodisperse and narrow. The "monodisperse distribution" as used herein means a single distribution of particle sizes. Generally, the distribution of the particles ranges from about 0.1 microns to about 0.4 microns, and for example from about 0.1 to about 0.3 microns.

The dispersions described herein are prepared by an emulsion process free of surfactants to obtain stable dispersions having up to 45% by weight of solids in water, which are obtained without a concentration step. Low levels of surfactants are added if the control of particle size is more desired, or to obtain higher levels of polymer emulsified in water (ie, 40-60% by weight). Any commercially available surfactant can optionally be pre-loaded or added discontinuously during or after the onset of polymerization to further manipulate particle size, particle number and particle distribution. It is well known in the art that the addition of more surfactant during the course of emulsion polymerization which already contains surfactants sometimes creates new particles and thus produces a bimodal distribution of particles or a broad particle distribution.

Accurate additional agents will readily occur to those skilled in the art and include anionic, cationic and nonionic surfactants. An exemplary dispersion is an anionic latex emulsion stabilized with surfactant having from 0 to 0.25% by weight of an anionic emulsifier. Examples of suitable perfluorinated anionic surfactants include perfluorinated ammonium octanoate, perfluorinated alkyl aryl carboxylates (metal) and perfluorinated alkyl / aryl lithium sulfonates (metal) in which the alkyl group has from about 1 to about 20 carbon atoms. carbon. Suitable surfactants also include ionic or nonionic surfactants, fluorinated surfactants based on hydrocarbons such as alkylbenzene sulphonates or mixtures of any of the foregoing.

Chlorofluoropolymers produced by the process of the invention can be isolated by conventional methods, such as by evaporating the water medium, freeze drying the aqueous suspension, or adding a minor amount of a binder or coagulating agent, such as carbonate. of ammonium, followed by filtration or centrifugation. Alternatively and preferably the chlorofluoropolymer dispersion produced is used as it is.

As noted briefly before, unlike other fluoropolymers that must be processed at temperatures above 260 ° C (ie, PTFE, FEP, PFA, ETFE, etc.), the chlorofluoro-olefin / fluoro-olefin dispersions as is described in the present description and the vinyl ester terpolymers thereof can be coated at temperatures below 120 ° C on paper and paper products. Examples of industrial uses for such non-limiting paper and paper products include packaging of foods, alcoholic beverages, perfumes and cosmetics, medical products and tobacco, in particular, coated paper imparted with moisture barrier property will be useful as a foil laminate. lid for blister packaging in pharmaceutical packaging. In addition, the value-coated documents with aqueous dispersions of chlorofluoro-olefin / fluoro-olefin copolymers as described in the present disclosure provide stain resistance to said documents.

In one embodiment, the chlorofluoro-olefin / fluoro olefin copolymers are coated on a paper or paper product substrate in multiple pass processes, although a one-step process can also be used. For example, the paper product can be immersed in the aqueous dispersions of chlorofluoro-olefin / fluoro-olefin copolymers described above. for a period of time ranging from about 60 seconds to 1 hour. As noted above, due to the unique nature of this particular dispersion, the application process is capable of occurring at ambient temperatures, for example of about 20-30 ° C. Thereafter, the paper product can be removed from the aqueous dispersion, and allowed to dry. The drying can be carried out at an elevated temperature to increase the speed at which the paper product is dried, for example, about 70-120 ° C in an oven. The drying process can also be accelerated thereafter, the application process can be repeated any number of times to produce the desired thickness of coating on the paper product of air or nitrogen, for example one, two, three, four , five, or more times.

The resulting paper or coated paper product is desirably hydrophobic, and does not allow the solvent such as isopropyl alcohol ("IPA"), toluene, or ethanol, for example, to penetrate through the paper. The coated paper also does not allow the oil or grease to penetrate through the paper and makes it resistant to stains. In addition, the coated paper is self-sealing by heating and the sealed paper maintains its properties. The coated paper also provides a barrier to moisture and aroma, and the moisture property and aroma barrier can be adapted by adjusting the thickness and type (for example, one-sided or two-sided) coating.

While in the description at least one previous detailed illustrative embodiment of the subject matter of the invention has been presented, it should be appreciated that there is a large number of variations. It should also be appreciated that the exemplary embodiment or the exemplary embodiments are only examples, and are not intended to limit the scope, applicability or configuration of the subject matter of the invention in any way. Rather, the above detailed description will provide experts in the art with a convenient roadmap for the implementation of an example of embodiment of the subject matter of the invention. It being understood that various changes may be made in the function and disposition of the elements described in an illustrative embodiment without departing from the scope of the subject matter of the invention as set forth in the appended claims.

Example 1 Dispersion preparation of terpolymer CTFE / VDF / Vinyl Propionate The terpolymer dispersion of CTFE / VDF / Vinyl Propionate with 80.1% by weight chlorotrifluoroethylene, 16.5% by weight of fluoride of vinylidene and 3.4% by weight of vinyl propionate. To prepare the polymer, a 3-gallon glass-lined autoclave was first filled with 1.57 liters of deionized water and then sprinkled with nitrogen to remove the oxygen. The autoclave was filled with 585 g of CTFE and 116 grams of VDF and heated to 19 ° C (66.2 ° F). 5.7 g of 70% solution of tertiary butyl hydroperoxide (TBHP) in water was further diluted to 35.7 ml with deionized water.4.4 grams of sodium metabisulfite (MBS) and 0.9 grams of ferrous sulfate heptahydrate were also diluted to 35.7 ml with deionized water. The two solutions are added separately to the autoclave for a period of ten minutes to initiate the polymerization. The temperature in the autoclave was maintained throughout the polymerization between 19 to 20 ° C. Polymerization was continued by the slow addition of two separate solutions consisting of TBHP (20.6 g in 142 ml of deionized water) and MBS (16.8 g in 142.8 ml in deionized water). After polymerization in 25 minutes, 108.4 ml of vinyl propionate was pumped into the autoclave throughout the polymerization at a rate equal to the consumption rate of CTFE and VDF. After the consumption of the initial CTFE and VDF loads, additional CTFE and VDF were added to the autoclave over a period of 4 hours to maintain a reactor pressure of 0.34 to 1.1 MPa. The total amounts of CTFE and VDF added to maintain the pressure is equal to 4222 grams and 837 grams of VDF, respectively. After the consumption of all the monomers (pressure decreases to <0.62 MPa), the autoclave was vented, producing 2 gallons of aqueous dispersion containing terpolymer of 31.2% polymer solids by weight.

Example 2 The coating of a paper uses the dispersion of Example 1 For the dispersion obtained in Example 1 2.0% by weight (based on the weight of the dispersion) of Capstone FS-32 fluorotensioactive (from Du Pont) was added and mixed with background. The mixture is applied on a laminated paper (from Coldenhove, The Netherlands) at room temperature using multiple passes to achieve a thickness of 38.1 microns of coating on each side of the paper. The total thickness of the coated paper corresponds to 124.46 microns. The coated paper was dried in an air oven at 80 ° C between the layers. Next, the coated paper was subjected to the MOCON tests at 40 ° C and 70% relative humidity to give a water vapor transmission rate of 0.0929 grams / 645.46 cm2 -day. By heating the coated paper to 175 ° C (~ 350 ° F), that heat is sealed and attempts to break the sealing results of the torn paper get stamped indicates that the stamp is intact

Claims (10)

1. - A coated substrate comprising: a substrate comprising cellulose fiber material; Y a copolymer applied on at least one surface of the substrate, the copolymer has at least two comonomer units of the formula: CX2CYA wherein each X is independently selected from the group consisting of H, C1 and F; Y is selected from the group consisting of H, Cl, F, 0 (CZ2) nCZ3, (CZ2) nCZ3, (OCZ2CZ2) nCZ3 and (0 (CZ2) n) nCZ3, wherein each n is independently from about 1 to about 12 and each Z is independently selected from the group consisting of H, Cl and F; and A is selected from the group consisting of H, Cl and F; provided that at least one comonomer unit, at least one of A, Y, y, or X or any Z is Cl.

2. - The coated substrate of claim 1, wherein the copolymer comprises at least one comonomer selected from the group consisting of chlorotrifluoroethylene, fluorotrichloroethylene, 1,1-dichlorodifluoroethylene, cis and trans isomers of 1,2-dichlorodifluoroethylene, 1-chloro-1 -fluoroethylene, l-chloro-2,2-difluoroethylene, vinylidene chloride, vinyl chloride, trichlorethylene, perchlorofluoro ether, perchlorofluorodioxoles, and mixtures thereof.

3. - The coated substrate of claim 2, wherein the copolymer comprises a chloroform-olefin copolymerized with at least one fluorinated monomer.

Four . - The coated substrate of claim 3, wherein the fluorinated monomer is selected from the group consisting of vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, vinyl fluoride, trifluoroethylene, fluorinated alkylvinylethers, perfluorinated alkyl vinyl ethers, 1,2-difluoroethylene, alpha- fluorinated olefins, perfluorodioxoles, and mixtures thereof.

5. - The coated substrate of claim 4, wherein the copolymer comprises chlorotrif luoroethylene copolymerized with a fluorinated monomer selected from the group consisting of vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene, vinyl fluoride, trifluoroethylene, fluorinated alkyl vinyl ethers, perfluorinated alkyl vinyl ethers , and mixtures thereof.

6. - The coated substrate of claim 5, wherein the copolymer further comprises a fluorinated alpha-olefin.

7. - The coated substrate of claim 5, wherein the copolymer further comprises a monomer selected from the group consisting of vinyl esters, acids and their sulfur analogs and non-halogenated alpha-olefins and mixtures thereof.

8. - The coated substrate of claim 7, the copolymer comprises a chloro olefin copolymerized with at least one fluoro-olefin and at least one alkyl vinyl ester.

9. - The coated substrate of claim 8, wherein the alkylninyl ester is selected from the group consisting of vinyl propionate, vinyl acetate, vinyl butyrate, vinyl isobutyrate, vinyl hexanoate, vinyl stearate, ethenyl ester neononanoate. , vinylester of versatic acid, vinylester of valeric acid, vinyl ester of caproic acid, lauric acid vinylester, vinylester of isovaleric acid, vinylester 2-ethylhexanoic, vinylester of 2,2-dimethyloctanoic acid, vinylester of 2-methyl-2- acid propyl-pentanoic, vinyl 4-methyl-4-butylhexanoic acid ester and neo-vinyl esters, and mixtures thereof.

10. - The coated substrate of claim 9, wherein the chlorofluoro-olefin is chlorotrifluoroethylene, said fluoro-olefin is the vinylidene fluoride, and said vinyl ester is vinyl propionate.