WO2005030860A1

WO2005030860A1 - Film-forming polymer compositions and films, coated substrates and laminate structures having a differential moisture vapor permeability formed therefrom

Info

Publication number: WO2005030860A1
Application number: PCT/US2004/030527
Authority: WO
Inventors: Robert H. Kelch
Original assignee: Dow Global Technologies Inc.
Priority date: 2003-09-22
Filing date: 2004-09-21
Publication date: 2005-04-07

Abstract

A polymer blend that includes a non-polar olefin polymer, a block copolyamide having a hydrophilic moiety and a compatibilizing polymer may be used as a singly ply film, one or more plies of a multi-ply film or a component of a fabric reinforced laminate structure. The film and laminate structure are suitable for use in a variety of application including housewraps, foam facers and underlayments.

Description

FILM-FORMING POLYMER COMPOSITIONS AND FILMS, COATED SUBSTRATES AND LAMINATE STRUCTURES HAVING A DIFFERENTIAL MOISTURE VAPOR PERMEABILITY FORMED THEREFROM Background of the Invention The present invention relates generally to film-forming polymer blend compositions, to films (either single ply or multi-ply) formed from such compositions, its woven or nonwoven substrates coated with such compositions and to laminate structures that include at least one ply formed from such compositions. A laminate structure typically comprises at least one ply of a woven or non- woven substrate in operative combination with at least one ply formed from a polymeric composition, preferably a ply formed from such polymer blend compositions. The films and laminate structures preferably have a differential moisture permeability (defined below). The present invention relates particularly to laminate structures wherein the substrate comprises synthetic fibers, especially olefin polymer fibers, and the polymer blend comprises a polyolefin, a block copolyamide and an effective amount of a compatibilizing polymer. The present invention more particularly relates to such laminate structures wherein the synthetic fibers are polyethylene fibers or polypropylene fibers and the polymer blend comprises a polyolefin, a block copolyamide having polymerized therein hydrophilic blocks, particularly those based on polyethylene glycol, and a compatibilizing polymer that contains an unsaturated carboxylic acid moiety, especially an acrylic acid or methacrylic acid moiety. The present invention also relates to the use of such a film, coated substrate or laminate structure in any of a variety of end use applications including weather-resistive barriers or sheathing membranes (more commonly known as housewrap materials), interior wall vapor retarder, facers for a polymer foam, roofing underlayment and concrete underlayment. A "weather-resistive barrier or sheathing membrane" generically refers to a flexible, sheet-like material, typically formed from woven or non- woven polymeric or cellulosic fibers. The materials function as one or both of air flow retarders and barriers to liquid (for example water) penetration. When used around the perimeter of residential and commercial buildings, such materials minimize, preferably eliminate, bulk liquid water penetration into wall cavity spaces such as those formed, at least in part, by wall studs and sheathing materials. Even with such a membrane in place, liquid water can, and often does, penetrate into such wall cavity spaces. In that event, the membrane or barrier desirably has at least a minimal amount of permeability to water vapor to permit diffusion of the vapor molecules from the wall cavity spaces through the sheathing membrane, sometimes referred to as a housewrap material, and to a space outside the wall cavity spaces. Illustrative conventional cellulosic sheathing membrane or weather-resistive barrier products include asphalt-saturated kraft paper, known widely as Grade D building paper, or asphalt-saturated cellulosic felt, sometimes referred to as #15 or #30 building felt. Section 1402.1 of the Uniform Building Code (UBC) published in 1997 by the International Conference of Building Officials (ICBO) states, in regard to exterior wall coverings, that "all weather-exposed surfaces shall have a weather-resistive barrier to protect the interior wall covering. Such barrier shall be equal to that provided for in UBC Standard 14-1 for kraft waterproof building paper or asphalt-saturated rag felt." The UBC Standard 14-1 requires that Grade D water- vapor permeable paper have a minimum water vapor transmission rate (WVTR) of 35 grams per square meter per 24 hours (g/m -24hr), which is equivalent to 5.0 US perm units (perms). Although these asphalt-saturated products do function as a wind resistant barrier and liquid water barrier, yet allow moisture vapor to diffuse through, and have been widely used in building and construction applications for many decades, those who work with sheathing membrane products desire more in terms of handling and performance. The asphalt- saturated products tend to be very heavy (typically 3.3 — 9 pounds per 100 square feet (lbs/100 ft²) (0.16 - 0.44 kilograms per square meter (kg/m²) for Grade D kraft paper; 7.5 - 12.5 lbs/100 ft² (0.37 - 0.61 kg/m²) for #15 felt; and 16 -27 lbs/100 ft² (0.78 - 1.32 kg/m²) for #30 felt) and exhibit low tear strength (for example typically 1 —3 pounds (lb) (0.45 to 1.4 kilograms (kg) in both machine direction (MD) and transverse direction (TD) when tested according to American Society for Testing and Materials (ASTM) D-l 117 (trapezoidal tear test). The asphalt-saturated membrane products are typically produced and sold in roll widths of 36 — 40 inches (0.9 — 1.0 meters), which means that three overlapping horizontal courses or plies are needed to cover a typical one "floor" or "story" of residential wall height. This requires significant builder effort and introduces overlap seams between the successive plies that serve as a potential entry point for water. The asphalt with which such products are impregnated makes them dirty to work with as the asphalt tends to rub off onto exposed body parts and articles of clothing or protective equipment that come into contact with such products. The asphalt-saturated or impregnated products also exhibit a tendency to rot and decay when exposed to moisture or weathering for extended periods of time. Finally, such products lose significant tensile strength and impact resistance when wet. Notwithstanding such shortcomings, the asphalt-saturated products have a desirable water vapor permeability or WVTR that typically ranges from 5 to 10 perms (35 — 70 g/m²- 24 hr) under dry conditions, and an even more desirable increased water vapor permeability when wet or under high ambient relative humidity. A desirable sheathing or weather-resistive barrier membrane product would eliminate the shortcomings of the asphalt-saturated products while retaining the desirable WVTRs of such products. ICBO Acceptance Criteria for Weather-Resistive Barriers AC38 (July 2000) defines paper-based barriers, felt-based barriers, and polymeric-based barriers and provides common standardized requirements for all Grade D equivalents. Sheathing membrane products based on synthetic polymer fibers (collectively referred to as "polymeric housewrap products"), whether woven or non-woven or as reinforcing scrim, provide desirable physical properties such as tensile strength, tear strength and impact resistance. Typical commercial polymeric housewrap products exhibit MD and TD ultimate tensile strengths of 30 — 50 pounds per inch (lb/in) (5250 to 8750 Newtons per meter (N/m)) (tested according to ASTM D-882) and trapezoidal tear strengths of 20 lb (9.1 kg) or greater (ASTM D-l 117). Fabrics usually exhibit a high degree of porosity to liquid water. In order to minimize this porosity, the fabrics may be coated with a microporous polymeric film or a solid, monolithic, moisture vapor permeable coating. Polymeric housewrap products find increasing acceptance based upon the aforementioned desirable physical properties as well as their light weight compared to the asphalt-saturated products (for example 1.2 to 2.4 lbs/100 ft² (0.06 - 0.12 kg/m²)) and availability in wide width rolls (for example 9-10 feet (ft) or 2.7 to 3 meters (m) wide). Such widths provide sufficient coverage for one story of residential wall height, thus significantly reducing builder time and effort required to install multiple sequential wraps as well as reducing the number of overlaps and seams, thus reducing potential for water infiltration into a wall cavity. Polymeric housewrap products can be used in building and construction applications as an equivalent substitute for asphalt-saturated building papers and felts as long as they meet the requirements set forth in UBC Standard 14-1 and ICBO AC38. They must also exhibit a minimum water vapor permeability of 35 g/m -24 hr or 5.0 perms. Additionally, polymeric housewrap films and laminates suitable for use as weather- resistive barriers or sheathing membranes must exhibit a minimum hydrostatic head water pressure resistance of 55 centimeters (cm) water head (55 millibars) and exhibit a minimum dry tensile strength in both MD and TD of 20 lb/inch (3500 Newtons per meter (N/m)). Polymeric housewrap products based upon polyethylene or polypropylene fibers provide an added benefit because their physical properties in general, and strength in particular, do not diminish when wet. Typical WVTR values for commercial polymeric housewrap products range from 5 to 60 perms (35 to 420 g/m²-24 hr) and remain fairly constant irrespective of ambient moisture or humidity level. Summary of the Invention A first aspect of the present invention is a film-forming polymer composition comprising a blend of (a) at least forty percent by weight, based on blend weight, of a non- polar polyolefin or non-polar olefin copolymer, (b) less than fifty percent by weight, based on blend weight, of a copolyamide block copolymer, and (c) a compatibilizing amount of an unsaturated carboxylic acid-modified polyethylene or ethylene copolymer, the copolyamide block copolymer having polymerized therein polyamide blocks and hydrophilic blocks, the hydrophilic blocks being present in an amount of at least 20 percent by weight, based on block copolymer weight, and being polyethers having at least 50 percent by weight, based on polyether weight, of -{C2H4-O) — units polymerized therein. A total of (a) plus (b) plus (c) equals one hundred percent by weight. A second aspect of the present invention is a polymeric film formed from the composition of the first aspect, the film having a dry cup water vapor permeability of at least 1.0 perm (7g/m²-24 hr), preferably at least 5.0 perms (35 g/m²-24 hr), when tested according to ASTM E-96, and exhibiting a wet cup water vapor permeability to dry cup water vapor (W/D) permeability ratio of at least 2.0, preferably at least 3.0. Such a ratio may be regarded as an indication of differential permeability. A third aspect of the present invention is a fabric reinforced laminate comprising a substrate having applied thereto at least one ply of the film of the second aspect, the substrate being a woven or nonwoven fabric comprising a non-polar olefin polymer, the olefin polymer being a homopolymer, a blend of two or more homopolymers, a copolymer, a blend of at least one homopolymer and at least one copolymer, or a blend of two or more copolymers, and having a first side and a second side, the film ply being applied to the first side or the second side or both the first side and the second side. A fourth aspect of the present invention is a coated fabric comprising a substrate having applied thereto a coating of the composition of the first aspect, the substrate being a woven or nonwoven fabric comprising a non-polar olefin polymer, the olefin polymer being a homopolymer, a blend of two or more homopolymers, a copolymer, a blend of at least one homopolymer and at least one copolymer, or a blend of two or more copolymers, and having a first side and a second side, the coating being applied to the first side or the second side or both the first side and the second side A fifth aspect of the present invention is a fabricated article comprising the polymeric film of the second aspect or the fabric reinforced laminate of the third aspect, or the coated fabric of the fourth aspect, the article being a housewrap, a roofing underlayment, a crawlspace or foundation underlayment, an insulation batting facer, an interior wall vapor retarder, or a facer for a foamed insulation board or plank. The second, third, and fourth aspects noted in preceding paragraphs establish practical utility, respectively, for the first, second and first aspects of the present invention. The fifth aspect provides utility for the second through fourth aspects. Description of the Preferred Embodiments The use of "comprising" necessarily includes the respectively and progressively narrower terms or limitations "consisting essentially of and "consisting of. Parameters expressed as ranges (for example from 1 to 4) include both endpoints (for example 1 and 4) unless stated otherwise. Expressions including a parenthetical term, such as (co) prior to "polyamide" or "polymer" refer to both the homopolymer and to copolymers based upon the term or word following the parenthetical term. Similarly, the parenthetical phrase (meth) prior to "acrylic acid" or "acrylate" refers, respectively, to both acrylic acid and methacrylic acid or both acrylate or methacrylate. "Polymer" generally includes, but is not limited to, homopolymers, copolymers (for example block, graft, random and alternating copolymers), terpolymers, and interpolymers as well as blends and modifications thereof. Unless otherwise specifically limited, "polymer" includes all possible geometrical configuration of the material (for example isotactic, syndiotactic and random symmetries). "Interpolymer" means a polymer having polymerized therein at least two different monomers and includes copolymers, terpolymers, tetra polymers and polymers having five or more different monomers polymerized therein. "Differential moisture vapor permeability" means that a material or structure has a "wet" dish permeability that is at least two times ("2X"), preferably at least three times ("3X"), and more preferably at least four times ("4X") that of its "dry" dish permeability. Both wet dish and dry dish permeability are measured in accord with ASTM Test E-96. "Nonwoven fabric or web" means a web having a structure of individual fibers or threads that are interlaid, but not in a regular, identifiable manner as in a knitted fabric. Conventional processes used to prepare nonwoven fabrics or webs include meltblowing processes, spunbonding processes, and bonded carded web processes. Nonwoven fabrics have a basis weight that is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm), where gsm = osy times 33.91, and the fiber diameters useful are usually expressed in micrometers (μm). "Spunbond fibers" refers to small diameter fibers formed by extruding molten thermoplastic material as filaments from a plurality of fine, usually circular capillaries of a spinnerette with the diameter of the extruded filaments then being rapidly reduced as by, for example, processes disclosed in Unites States Patent (USP) 4,340,563, USP 3,692,618, USP 3,802,817, USP 3,338,992, USP 3,341,394, USP 3,502,763, USP 3,502,538, and USP 3,542,615. The teachings of the foregoing references are incorporated herein by reference. Spunbond fibers are generally not tacky when they are deposited onto a collecting surface and require an additional thermal, adhesive or other bonding step to integrate the web. Spunbond fibers are generally continuous and have diameters larger than (>) 7 μm, more particularly, between 10 and 30 μm. "Microfibers" refers to small diameter fibers having an average diameter no greater than (<) 75 μm (for example an average diameter of from 0.5 μm to 50 μm, more particularly from 2 to 40 μm). "Denier", another frequently used expression of fiber diameter, is defined as grams (g) per 9000 meters (m) of a fiber. A fiber diameter expressed in μm may be converted to denier by squaring, and multiplying the result by 0.00629. Thus, a 15 μm polypropylene fiber has a denier of 1.42 (15² x 0.00629 = 1.415). "Meltblown fibers" means a fiber formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity gas (for example air) streams that attenuate the filaments of molten thermoplastic material to reduce their diameter to, for example, microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and deposited on a collecting surface to form a web of randomly disbursed meltblown fibers. Such a process is disclosed, for example, in USP 3,849,241, the teachings of which are incorporated herein by reference. Meltblown fibers may be continuous or discontinuous, are generally smaller than 10 μm in diameter, and are generally tacky and self-bonding when deposited onto a collecting surface. Film-forming compositions of the present invention comprise a blend of an amount of at least (>) 40 percent by weight (wt%), based on blend weight, of a non-polar polyolefin or non-polar olefin copolymer, an amount of less than (<) 50 wt%, based on blend weight, of a copolyamide block copolymer, and a compatibilizing amount of an unsaturated carboxylic acid-modified polyethylene or ethylene copolymer. The three amounts total 100 wt%, based on weight of the blend. Suitable non-polar polyolefins are selected from polyolefins, including high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and polypropylene (PP), especially isotactic PP, syndiotactic PP and rubber toughened PP. These polyolefins do not contain, and are not modified by, a polar functional monomer. A non-polar olefin copolymer can comprise one or more of; a heterogeneous ethylene/α-olefin interpolymer, preferably a heterogeneous ethylene/C₃-C₈ α-olefin interpolymer wherein the alpha-olefin (α-olefin) contains three to eight carbon atoms (C₃- C₈), most preferably a heterogeneous ethylene/octene-1 interpolymer; or a homogeneous ethylene/α-olefin interpolymer, including a substantially linear ethylene/α-olefin interpolymer, most preferably a substantially linear ethylene/C₃-C₈ α-olefin interpolymer; or a thermoplastic olefin, preferably an ethylene/propylene rubber (epm) or ethylene/propylene diene monomer terpolymer (epdm); or a propylene/α-olefin interpolymer, preferably a heterogeneous propylene/ethylene or propylene/C -C₈ α-olefin interpolymer; and any and all combinations thereof. The homogeneous ethylene/α-olefin interpolymers, sometimes genetically referred to as metallocene polymers or m-polymers, include both linear and substantially linear ethylene/α-olefin interpolymers. Especially preferred non-polar polyolefins include polyethylene plastomer made with metallocene catalyst with densities of 0.86-0.92 grams per cubic centimeter (g/cc) ("mPE"). The C₃-C₈ α-olefins include propylene, butene, pentene, hexene, heptene and octene and all of their isomers. Ethylene/α-olefin interpolymers can be further characterized by their degree of long or short chain branching and the distribution thereof. Linear olefin polymers which have an absence of long chain branching, such as the traditional LLDPE or HDPE made using Ziegler polymerization processes (for example USP 4,076,698), are sometimes called heterogeneous polymers. HDPE consists mainly of long, linear polyethylene chains and usually has a density of > 0.94 g/cc as determined by ASTM D 792. HDPE also has a melt index (MI) of from 0.01 to 1000, and preferably from 0.01 to 100, more preferably from 0.05 to 50 grams per 10 minutes (g/10 min) (as determined by ASTM test method D 1238, condition 190°C/2.16 kilograms (kg) weight). Heterogeneous LLDPE generally has a density of from 0.85 to 0.94 g/cc (ASTM D 792), and a MI of from 0.01 to 1000, and preferably from 0.01 to 100, more preferably from 0.05 to 50 g/10 min (ASTM D 1238, condition 190°C/2.16 kg). Heterogeneous LLDPE is preferably an interpolymer of ethylene and one or more C₃-Cι₈ α-olefins, more preferably C₃-C₈ α-olefins. Preferred comonomers include 1 -butene, 4-methyl-l- pentene, 1 -hexene, and 1 -octene. Uniformly branched or homogeneous polymers (for example homogeneous polyethylene and homogeneous ethylene/α-olefin interpolymer) contain no long chain branches and have only branches derived from the monomers (if the monomer has more than two carbon atoms). Homogeneous polymers include those made as described in USP 3,645,992, and those made using so-called single site catalysts in a batch reactor having relatively high olefin concentrations as described in USP 5,026,798 and USP 5,055,438. The uniformly branched/homogeneous polymers have, within a given interpolymer molecule, a random comonomer distribution. For a given interpolymer, the interpolymer molecules have a similar ethylene/comonomer ratio. Substantially linear olefin polymers have a processability similar to LDPE, but the strength and toughness of LLDPE. Substantially linear olefin polymers are disclosed in USP 5,272,236 and USP 5,278,272, the entire contents of which are incorporated herein by reference. Substantially linear olefin polymers have a density of from 0.85 g/cc to 0.97 g/cc (ASTM D-792), preferably from 0.85 g/cc to 0.955 g/cc, and especially from 0.85 g/cc to 0.92 g/cc. Such polymers have a MI of from 0.01 to 1000, and preferably from 0.01 to 100, more preferably from 0.05 to 50 g/10 min (ASTM D 1238, Condition 190°C/2.16 kg). Particularly suitable substantially linear olefin polymers have a density of from 0.91 g/cc to 0.96 g/cc and a MI of 1.0 to 50.0 g/10 min. Such polymers are available from The Dow Chemical Company under the trade name AFFINITY™ and DuPont Dow Elastomers LLC under the trade name ENGAGE™. "Propylene polymer" means a polymer in which at least 50 wt% of its monomeric units are derived directly from propylene. Appropriate propylene interpolymers include random, block, and grafted copolymers or interpolymers of propylene and an olefin selected from the group consisting of ethylene, C4-C10 1-olefins, and C4-C10 dienes. Propylene interpolymers also include random terpolymers of propylene and 1-olefins selected from the group consisting of ethylene and C4-C 1-olefins. The C4-C10 1-olefins include the linear and branched C4-C1 Q 1-olefins such as, for example, 1 -butene, isobutylene, 1-pentene, 3- methyl-1 -butene, 1 -hexene, 3,4-dimethyl-l -butene, 1-heptene, 3 -methyl- 1 -hexene, and the like. Examples of C4-C10 dienes include 1,3-butadiene, 1,4-pentadiene, isoprene, 1,5- hexadiene, and 2,3-dimethyl- 1 ,3-hexadiene. The propylene polymer material may be comprised solely of one or more propylene homopolymers, one or more propylene copolymers, and blends of one or more of each of propylene homopolymers and copolymers. The propylene polymer material preferably comprises at least (>) 70, more preferably > 90, and even more preferably 100, wt% propylene monomer derived units (that is, the propylene homopolymers are preferred). The propylene polymer preferably has a weight average molecular weight (M_w) of >

100,000. M_w can be measured by known procedures. The propylene polymer material preferably also has a melt flow rate (MFR) of > 0.01 more preferably > 0.05, even more preferably > 0.1 g/10 min, and even more preferably > 0.5 g/10 min up to 100 g/10 min, up to (<) 50, preferably < 20, and more preferably < 10, g/10 min. Throughout this description, "MFR" refers to a measurement conducted according to ASTM D-1238 condition 230°C/2.16 kilograms (kg) (Condition L). Preferred propylene polymers include those that are branched or lightly cross- linked. Branching (or light cross-linking) may be obtained by those methods generally known in the art, such as chemical or irradiation branching/light cross-linking. One such resin which is prepared as a branched lightly cross-linked polypropylene resin prior to using the polypropylene resin to prepare a finished polypropylene resin product and the method of preparing such a polypropylene resin is described in USP 4,916,198, the teachings of which are hereby incorporated by reference. Another method to prepare branched/lightly cross-linked polypropylene resin is to introduce chemical compounds into the extruder, along with a polypropylene resin and allow the branching/lightly cross- linking reaction to take place in the extruder. This method is illustrated in USP

3,250,731 with a polyfunctional azide, USP 4,714,716 (and published International Application WO 99/10424) with an azidofunctional silane and EP 879,844-Al with a peroxide in conjunction with a multi-vinyl functional monomer. The aforementioned U.S. patents are incorporated herein by reference. USP 5,605,936 and USP 5,883,151, the teachings of which are also incorporated by reference, illustrate irradiation techniques. The non-polar polyolefins and non-polar olefin copolymers suitable for use in compositions of the present invention lack a polar moiety or polar functionality found in other ethylene-based polymers such as a copolymer of ethylene with an alkyl ester of an ethylenically unsaturated organic carboxylic acid (for example acrylic acid or methacrylic acid, collectively designated as "(meth)acrylic acid"). The non-polar polyolefins and non-polar olefin copolymers also lack other common polar moieties like a vinyl ester such as vinyl acetate or a hydroxyl group. Illustrative commercially available ethylene/vinyl acetate (EVA) copolymers (with a VA content of 4 to 40 wt%, based on copolymer weight) include EL VAX resin (trademark of E. I. du Pont de Nemours and Company); ESCORENE^™ resin (trademark of ExxonMobil Chemical Company), ULTRATHENE^™ resin (trademark of Equistar Chemicals), and EVATANE^™ resin (trademark of AtoFina Chemical). EVA copolymers may contain copolymerized or grafted monomers such as maleic anhydride (MAH) in addition to a carboxyl-containing monomer. Hydroxyl group containing polymers include copolymers of ethylene/vinyl alcohol (EVOH), typically with 52 mole percent (mol%) to 73 mol% of vinyl alcohol comonomer are supplied under tradenames such as EVAL ^™ resins (trademark of EVAL Company of America) and SO ARNOL resins (trademark of Nippon Gohsei). Polymers made totally from vinyl alcohol are known as polyvinyl alcohol (PVOH) polymers and are available under the tradename ELVANOL ^™ (E. I. du Pont de Nemours and Company). Compositions of the present invention include a compatibilizing amount of an unsaturated carboxylic acid-modified polyethylene or ethylene copolymer. The unsaturated carboxylic acid-modified polyethylene or ethylene copolymer is desirably an ethylene/acrylic acid (EAA) copolymer or an ethylene/methacrylic acid (EMAA) copolymer (collectively referred to as "ethylene/(meth)acrylic acid copolymers") with an acid content of > 6.5 wt%, based on copolymer weight, preferably > 9 wt%. The compatibilizing amount is > 5 wt%, based on composition weight, preferably within a range of from 5 to 25 wt%, and more preferably within a range of from 5 to 20 wt%, based on composition weight. The unsaturated carboxylic acid-modified polyethylene or ethylene copolymer is preferably a blend of at least two ethylene/(meth)acrylic acid copolymers that have different (meth)acrylic acid contents. One of the contents is > 6.5 wt%, based on copolymer weight, and the other content is > 10 wt%, based on copolymer weight. One suitable blend includes an EAA copolymer with an AA content of 9.7 wt% and an EAA copolymer with an AA content of 20 wt%, both percentages being based on copolymer weight. Suitable EAA copolymers may be obtained from The Dow Chemical Company under the trade name PRIMACOR™. Commercially available EMAA copolymers include those commercially available from E. I. du Pont de Nemours and Company under the trade designation NUCREL^™. Commercially available ethylene/methyl acrylate/acrylic acid terpolymers (EMAAA) include those commercially available from Exxon Chemical under the trade name ESCOR ^™ ATX resins. Acrylic acid grafted polyolefins include those commercially available from BP Chemical under the trade designation POLYBOND ™. Carboxylic-acid functional polyolefins with "anhydride functionality" refers to polymers resulting from a reaction to graft an ethylenically unsaturated carboxylic acid anhydride, such as MAH, onto a polymer backbone. Polyethylene (PE), polypropylene (PP) and ethylene copolymers, such as EVA serve as suitable backbone polymers. Commercially available MAH-grafted (MAH-g) polyolefins include BYNEL^™ CXA and FUSABOND^™ resins (E. I. du Pont de Nemours and Company), PLEXA ^™ (Equistar Chemicals) and LOTADER^™ (AtoFina). Styrenic block copolymers with MAH-grafted, such as MAH- grafted styrene-ethylene-butylene-styrene (SEBS-g-MAH) and MAH-grafted styrene- butadiene-styrene (SBS-g-MAH), are available under the tradenames of KRATON™ (Kraton Company) and VECTOR™ (DuPont-Dow Elastomers). Typical MAH-g polymers have a MAH content of from 0.05 to 1.5 wt%, based on total polymer weight. Additionally, polyolefin polymers and copolymers with glycidyl methacrylate or other epoxide functionality either grafted or copolymerized into the copolymer exhibit similar reactive, adhesive and compatibilization properties. A copolymer polymerized from ethylene and glycidyl methacrylate (8 wt% GMA) and a terpolymer polymerized from ethylene, methyl acrylate (25 wt%), and glycidyl methacrylate (8 wt%) are available as compatibilizers under the tradename LOTADER (AtoFina). Ionomers function as suitable replacements for acid- and acid anhydride- functionalized polyolefins. "Ionomers" typically refers to ionomerized metal salts of carboxylic acid copolymers, such as sodium, potassium or zinc ionomers of EAA or EMAA. Commercially available ionomers include those available under the trade designation SURLYN^™ (E. I. du Pont de Nemours and Company). Polar-functional polyolefins, including carboxylic acid- or acid anhydride-functional polyolefin polymers, generally have a density of 0.86 to 1.03 grams per cubic centimeter (g/cm³ or g/cc), preferably 0.89 to 0.97 g/cc (ASTM method D-792), and a MI of 0.5 to 1000 g/10 min, preferably 1 to 300 g/10 min, more preferably 2 to 20 g/10 min (ASTM method D-1238 at 190°C using a 2.16 kg load). Compositions of the present invention also include less than (<) 50 wt%, based on composition weight, of a copolyamide block copolymer. The copolyamide block copolymer has polymerized therein polyamide blocks and hydrophilic blocks, the hydrophilic blocks being present in an amount of > 20 wt%, preferably > 25 wt%, more preferably > 30 wt%, still more preferably > 35 wt%, and most preferably > 40 wt%, based on block copolymer weight and being polyether diols having > 50 wt%, preferably > 55 wt% and more preferably > 60 wt%, based on polyether weight, of -(C2H4-O) — units polymerized therein.

The block copolymers result from the polycondensation of polyamide blocks with reactive end groups with the polyether blocks having reactive end groups. The polyamide blocks can be formed from, for example, condensation of at least two alpha, omega (α,Ω)- aminocarboxylic acids or of two lactams or of a lactam with an α,Ω-aminocarboxylic acid or of at least one α,Ω-aminocarboxylic acid (or lactam) with at least one diamine and at least one dicarboxylic acid. Suitable dicarboxylic acids include, but not limited to, adipic acid, sebacic acid and dodecanedioic acid. Suitable α,Ω-aminocarboxylic acids include, but are not limited to, aminoundecanoic acid and aminododecanoic acid. Suitable lactams include, but are not limited to, lauryllactam and caprolactam. Suitable diamines include aliphatic and aryl diamines, such as ethylenediamine, hexamethylenediamine, piperazine, propylene glycol diamine, and methyl pentamethylenediamine. The hydrophilic blocks are polyether diols comprised of, but not limited to, polyethylene glycol, polypropylene glycol, polytetramethylene glycol or other suitable glycols, with the limitation that > 50 wt% of the glycol block, based on polyether weight, have polyethylene ethylene glycol derived ethylene oxide -{C2H4-O) — units polymerized therein. Having hydrophilic blocks comprise greater than 65 wt% of the copolymer will adversely affect the mechanical integrity and strength properties of the copolyamide, particularly when wet. The amide blocks comprise > 35 wt%, preferably > 40 wt%, more preferably > 45 wt%, still more preferably > 50 wt %, but desirably no more than (≤) 80 wt%, preferably < 75 wt%, more preferably < 70 wt% and most preferably < 65 wt% of the copolyamide polymer, all wt% being based on copolyamide weight. In order to achieve blendability and compatibility with the polyolefin components of the herein disclosed composition, the copolyamide must have a melting point of < 150°C, and preferably < 135°C. For blendability and phase morphology dispersion, the copolyamide desirably exhibits a low viscosity, as indicated by a MI of > 20 g /10 min, and more preferably > 40 g/10 min when tested according to ASTM method D-1238 at 190⁹C using a 2.16 kg load. Prepare a particularly preferred low molecular weight block copolymer copolyamide via a two step reaction process. In step one, make a copolyamide of caprolactam and aminoundecanoic acid with sebacic acid to cap the end groups. In step two, react the diacid end groups of the copolyamide block with hydroxyl end groups of the polyether diol blocks, such as polyethylene glycol (PEG) blocks, to form an ester linkage. A desired composition can be formed from a block copolymer comprised of 46 wt% PEG block, with a nominal number average molecular weight (M_n) of 580, and 54 wt% of a copolyamide block, both percentages being based on composition weight. The molar composition of the preferred copolyamide is nominally 10 mol% of caprolactam, 63 mol% of aminoundecanoic acid, and 27 mol% of sebacic acid, and the M_n of the copolyamide block is nominally 680. The preferred low M_n block copolymer copolyamide has a melting point of 125-130°C, as determined by Differential Scanning Calorimetry (DSC), a MI of 157 g/10 min (190°C, 2.16 kg load), and a specific gravity of 1.09. Because of the relatively low M_n and low viscosity of the herein described copolyamide resins, they are difficult to process on conventional film or sheet extrusion equipment that has been designed for high M_n polymers. Additionally, the resins exhibit relatively low tensile and tear strength properties and are tacky or sticky when extruded into monolayer films. Polymer blend compositions containing more than 50 wt% of a low M_n copolyamide tend to have undesirable tensile strength, impact values, low tear strength, and low adhesion to non-polar polymers. The copolyamide fraction also becomes the major continuous phase within the composition moφhology; and the film tends to exhibit reduced physical properties when wet or saturated with water. The present blend compositions overcome the limitations inherent in the low M_n copolyamide resins used in this invention. Transmission electron microscopy (TEM) of the phase moφhology of films made from varying compositions of copolyamide and polyolefin resins in conjunction with a compatibilizing amount of an unsaturated carboxylic acid-modified ethylene homopolymer or ethylene copolymer shows that at compositions above 50 wt% of copolyamide, the polyolefin polymers are a dispersed phase within a continuous copolyamide matrix. This copolyamide-continuous moφhology results in poor interlayer adhesion of this highly polar copolymer to desired nonpolar polyolefin substrates such as polypropylene and polyethylene woven and nonwoven fabrics or textiles. At blend compositions below 25 wt% copolyamide, the polyolefin components form a continuous polyolefin matrix, which although providing excellent adhesion properties to nonpolar polyolefin substrates and excellent physical properties, results in significantly reduced water vapor permeability through a film. The continuous polyolefin matrix appears to totally encapsulate the moisture absorbent and vapor breathable copolyamide fraction thus reducing water vapor transmission through the film. As evidenced by TEM photomicrographs, a desired co- continuous inteφenetrating network of both polyolefin and copolyamide phases exists in the composition range of from 25 wt% to 45 wt% copolyamide and 55 wt% to 75 wt% total polyolefin (comprised of both the non-polar polyolefin and the carboxylic-acid modified polyethylene or ethylene copolymer compatabilizer) the percentages being based on composition weight and selected to total 100 wt%. This co-continuous phase moφhology provides the desired moisture vapor breathability and transport characteristic of the copolyamide while providing the physical properties (tensile strength, toughness, tear strength) of the polyolefin matrix and desired adhesion properties to woven and nonwoven non-polar polyolefin (preferably polypropylene and polyethylene) fabrics or textiles. Because the preferred co-continuous phase moφhology of the copolyamide phase and the polyolefin phase can be influenced by factors such as degree of mixing, extent of applied shear forces, specific blend composition, viscosity or melt index of the individual polymers utilized, process temperatures, and degree of compatibilization achieved by use of different carboxylic acid-modified ethylene homopolymer or ethylene copolymer resins or amounts, the composition range of from 25 wt% to 45 wt% copolyamide is a "best fit" guideline rather than an absolute requirement. The aforementioned factors may, in some cases, yield satisfactory results in terms of desired moisture vapor permeability characteristics outside this range. The present invention focuses upon blends of a copolyamide block copolymer with a non-polar polyolefin or non-polar olefin copolymer in contrast to blends of a copolyamide block copolymer or other amide polymer with a polar olefin polymer such as those taught in USP 6,451,912. Polar olefin copolymers, such as copolymers of ethylene with vinyl acetate, methyl acrylate, ethyl acrylate, n-butyl acrylate or acrylic acid, typically have a crystalline melting point (determined via DSC according to ASTM D-3417) below 100°C. As the percentage of comonomer (for example vinyl acetate) in a copolymer increases, the crystalline melting point tends to decrease, quite probably due to a concurrent decrease in polymer crystallinity. The crystalline melting point decreases to a temperature within a range of from 65 to 95°C, with many of the aforementioned ethylene copolymers reaching a crystalline melting point of < 85°C with increased comonomer contents. Many of these olefin copolymers also have a Vicat softening point (ASTM D-1525) < 85°C, sometimes < 70°C. In practical terms, as crystalline melting point and Vicat softening point temperatures decrease with increasing comonomer content, an ethylene copolymer resin becomes increasingly tacky and exhibits an increasing tendency to block or stick to itself, especially at elevated temperatures such as those experienced in a closed shipping container exposed to sunlight on a warm or hot summer day in a State such as Texas. Blocking may be so severe that a roll of film made from such a polymer might effectively become a solid cylinder or unroll only with great difficulty and consequent tearing. The same would hold true if such a resin were coated onto a fabric or other substrate and the coated fabric or substrate were formed into a roll and put in the same shipping container. A probable benefit of an increasing polar comonomer content in an ethylene copolymer resin is a concurrent increase in adhesion to, and compatibility with, other polar polymers, such as a copolyamide, as well as adhesion to substrates or fabrics made from a polar polymer such as a polyester. A trade-off to this benefit is a reduction in adhesion to substrates made from non-polar polymers such as PP and polyethylene (PE). In the current application, excellent adhesion of the claimed film-forming polymer composition, especially in film form, to a non-polar polyolefin is required in order to achieve suitable performance adhesion to polyolefin woven and nonwoven fabric substrates. Non-polar polyolefins, such as PE and PP, generally have a crystalline melting points greater than (>) 100°C, with some resins exhibiting melting points of 125°C or greater (>). These resins have a reduced tendency, relative to the ethylene copolymers with increasing polar comonomer contents, to exhibit blocking or tackiness caused by hot ambient temperatures or solar irradiation. They tend to exhibit excellent adhesion properties to non-polar substrates such as woven and nonwoven fabrics made from PP and PE. Non- polar polyolefins are, however, generally incompatible with polar resins, such as copolyamide, thus necessitating the use of a compatibilizing amount of polar-functional compatabilizer, such as the carboxylic acid functional ethylene copolymers described above. The film-forming polymer compositions of the present invention may also include one or more conventional additives that impart a functional attribute to the films, but do not significantly detract from film physical properties, moisture vapor transmission or adhesion properties. Such additives include, without limitation, antioxidant or process stabilizers, ultraviolet (UV) stabilizers, tackifiers, fire retardants, inorganic fillers, biocides, slip additives, and pigments. The additives typically total no more than 40 parts by weight (pbw) per 100 pbw of polymer blend (copolyamide, non-polar olefin (co)polymer and compatibilizer). Polymeric films fabricated from polymer compositions of the present invention may be of any gauge that serves a given need, but typically fall within a range of from 0.5 to 50 mils (13 to 1270 μm), preferably 1 to 20 mils (25 to 508 μm) and most preferably 1 to 10 mils (25 to 254 μm). Any conventional film forming process may be used to fabricate such films. Illustrative processes include, without limitation, an annular extruded blown film process, a slot die cast extrusion film process, and extrusion coating of one or more layers upon a film or substrate (for example a woven or non- woven fabric). The films of the present invention can be monolayer films or function as one or more layers of a multi-layer film construction. Such multi-layer films preferably result from coextrusion processes as well as lamination processes. In addition, the polymer blend compositions described herein can be dissolved in solvent or dispersed as an aqueous dispersion or emulsion and coated from a liquid phase using conventional liquid coating processes. The film-forming compositions of the present invention comprise a blend of > 40 wt%, based on blend weight, of a non-polar polyolefin or non-polar olefin copolymer, < 50 wt%, based on blend weight, of a particular copolyamide block copolymer, and a compatibilizing amount of an unsaturated carboxylic acid-modified polyethylene or ethylene copolymer. Such blends exhibit MI values that range from 5 to 100 g/10 min (ASTM D- 1238, 190^SC, 2.16 kg load), depending upon the initial MI of each blend component. Conventional upward blown film production typically uses resin compositions with an overall weighted average MI of from 1 to 6 g/10 min. Conventional cast film production usually employs resins with weighted average MI values of from 3 to 30 g/10 min. Extrusion coating routinely requires an even higher weighted average MI, typically within a range of from 8 to 50 g/10 min, in order to achieve sufficient high speed coating and flow onto (and into a porous) substrate. The weighted average MI of a polymer blend can be estimated by using a logarithmic weighted average of the individual MI values of each resin component of the blend. This estimate can be calculated by summing the weighted average (percentage) of the logarithm of the MI value of each blend component, and then taking the inverse of the logarithm of the sum. As an example, to calculate the estimated weighted average MI of a polymer blend of three resins, each with a known MI (Ml, M2, M3), that comprise the blend with three fractional percentages (Al, A2, A3, such that all three fractions sum to 1.0), the logarithmic weighted average is determined according to the equation: Al*log(Ml) + A2*log(M2) + A3*log(M3) = X The polymer blend estimated melt index (MI_est) is then determined from the logarithmic inverse of X, defined according to the equation: MI_eS, = 10 exp.(X) or l0^x Polymeric housewrap products can be used in building and construction applications as an equivalent or substitute for asphalt-saturated building papers and felts as long as they meet the requirements set forth in UBC Standard 14-1. All housewrap products are thus required to exhibit a minimum water vapor permeability of 35 g/m²-24 hr or 5 perms. Films or coatings formed from the polymer composition of the present invention, laminates formed, at least in part, from such films, and coated fabrics including such coatings, all share a common characteristic. They provide a dry cup water vapor permeability of at least 5 perms (35 g/m²-24 hr), preferably > 10 perms (70 g/m²-24 hr), when tested according to ASTM E-96, and exhibit a W/D ratio of > 2.0, preferably > 3.0. These permeability values or traits allow the films, coatings, laminates and coated fabrics to be classified as liquid water impermeable/water vapor permeable or "breathable". They retain a sufficient level of the copolyamide component's desirable characteristics to provide a film, coated fabric or fabric-reinforced laminate with desirable performance, including adhesion to a non-polar woven or non- woven fabric. This contrasts with the compositions of USP 6,432,548 noted above which have a polyolefin dispersed phase, particularly those with a functionalized polyolefin dispersed phase, which do not adhere well to a non-polar woven or non-woven fabric, non-polar resin or non-polar substrate. Films formed from the polymer composition of the present invention exhibit ultimate tensile strengths in the machine direction (MD) and transverse direction (TD) that are preferably > 2,000 pounds per square inch (psi) (14 megapascals (MPa)), more preferably > 2,500 psi (17.2 MPa), still more preferably > 3,000 psi (20.7 MPa), ultimate elongation of > 400%, and 2% secant modulus values of 4,000 psi (28 MPa) to 30,000 psi (207 MPa) when tested according to ASTM method D-882. More preferably, the films further exhibit MD and TD Ermendorf tear strengths of greater than 10 grams/mil (0.4 g/μm), and preferably greater than 20 g/mil (0.8 g/μm) when tested according to ASTM method D- 1922. Films formed from the polymer composition of the present invention have a hydrostatic head or water column height resistance, determined as shown below, of at least 55 centimeters (cm) of water (55 millibars). Such films also exhibit a water absoφtion weight gain, also determined as shown below, within a range of 2 to 10 percent. Polymeric housewrap films and laminates suitable for use as weather-resistive barriers or sheathing membranes must exhibit minimum dry tensile strength in both MD and TD of > 20 lb/inch (3500 N/m) according to UBC Standard 14-1. Films having these aforementioned properties are sufficiently durable for subsequent conversion operations (for example, thermal lamination and HF-welding) and for end use applications such as housewrap, interior wall vapor retarder films, roofing underlayment film and laminates, fiber insulation batting facer laminate, rigid foam insulation sheathing facer laminate, and various other free-film and textile laminates. Skilled artisans readily understand that for a given physical property such as a minimum tensile strength of 20 lb/in (3500 N/m) needed to comply with UBC Standard 14-1, one must use a greater gauge or thickness for an unreinforced or "stand alone" film than for a reinforced films, such as a fabric-reinforced film, to achieve equivalent results. For a film composition exhibiting a nominal 2,000 psi (14 MPa) tensile strength, a minimum film gauge of 10 mils (254 μm) would be sufficient to meet this 20 lb/in (3500 N/m) requirement. A "stand alone" film composition exhibiting a 3,000 psi (21 MPa) tensile strength would need to be produced at a minimum of 6.7 mils (170 μm) to sufficiently meet the 20 lb/in (3500 N/m) tensile strength. Films of the present composition can also be thermally laminated, sealed or welded using conventional thermal processes such as hot roll lamination, flame lamination, calendaring and heat sealing. One illustration of such a combination involves a first step of thermally laminating a film of the present invention to a substrate such as a fabric thereby forming a film fabric composite. Pre-extruded films can be combined with another substrate using an extrusion lamination process where a molten polymeric monolayer or coextruded extrudate is first extruded onto a substrate, such as a textile, and simultaneously the premade polymeric film is laminated or nipped onto the molten polymer, thus creating a film / molten polymer extrudate / substrate composite, which is then chilled and wound into a product roll. Further extensions of lamination include the use of conventional liquid coating and lamination processes whereby a liquid dispersion, emulsion or solution of a polymer or adhesive is applied to the film or substrate using well-known coating processes such as gravure roll, transfer coating, Meyer rod, spray coating, and slot die coating.

Additional substrates of interest onto which films of the present invention can be laminated include cellular foams, such as polystyrene, polyurethane, isocyanurate, or polyolefin foams, woven or nonwoven fabrics, paper or paperboard products, thermoplastic film or sheet, wood veneer or wood products, and wood or cellulosic composites. The laminate structures of the present invention comprise an operative combination of at least one fabric ply and at least one polymer film ply. As used herein, "operative combination" means that the polymer film ply has an adhesion to the fabric ply, determined using hot bar sealing test procedures detailed beow, of at least 0.7 lb/in (123 N/m), preferably at least 1.0 lb/in (175 N/m). At less than 0.7 lb/in (123 N/m) adhesion between the polymer film ply and fabric ply (also known as "inteφly adhesion"), adverse performance results. Such adverse performance may be evidenced by delamination or separation of the film ply from the fabric ply during routine handling or upon exposure to wind and rain or even when unwinding a roll of laminate that exhibits some blocking or tackiness. While there is no real upper limit on adhesion from a performance point of view, procedures or materials used to achieve adhesion levels well in excess of 175 N/m may increase product cost to a point where it is not considered an economic alternative. An operative combination may be effected by any means known to those skilled in the art, including the use of an adhesive. Thermal lamination and extrusion coating yield particularly suitable results. If desired, a polymer film ply may be sandwiched between two fabric plies or, alternatively, a fabric ply may be sandwiched between two polymer film plies. Laminate structures of the present invention need not, however, be limited to two or three ply structures. By alternating fabric plies and polymer film plies, one can easily fabricate laminate structures with four, five, six, and seven or more layers. While laminate structures with an odd number of layers are typically symmetric when the structure consists only of fabric plies and polymer film plies, adding a ply formed from a material other than that of the aforementioned fabric plies and polymer film plies, offers the possibility for an asymmetric structure as does the use of an even number of plies of each of said fabric and polymer film. The polymer film ply comprises a blend of at least three components, a polyolefin component, a copolyamide component and a compatibilizer component (unsaturated carboxylic acid-modified PE or ethylene copolymer). The copolyamide component is present in an amount of from 20 wt% to < 50 wt%, based on blend weight, preferably from 25 wt% to 45 wt%, more preferably from 25 wt% to 40 wt% and most preferably about 40 wt%. The non-polar polyolefin component is present in an amount of from 75 wt% to 45 wt%, based on blend weight, preferably from 70 wt% to 45 wt%, more preferably from 60 wt% to 50 wt% and most preferably about 55 wt%. The compatibilizer component is present in a compatibilizing amount, typically from 5 wt% to 20 wt%, based on blend weight, preferably from 5 wt% to 15 wt%. The amounts of copolyamide component, polyolefin component and compatibilizer component, when added together, total 100 wt%. Illustrative preferred film-forming polymer compositions include the following: A) 30 wt% copolyamide (PLATAMID™ HX 2585T, Atofina), 60 wt% mPE (AFFINITY™ PL1280, The Dow Chemical Company), 5 wt% EAA copolymer (9.7 wt% acrylic acid content, PRIMACOR™1430, The Dow Chemical Company), and 5 wt% EAA copolymer (20 wt% acrylic acid content, PRIMACOR™5980i, The Dow Chemical Company); B) 40 wt% copolyamide (PLATAMID™ HX 2585T, Atofina), 50 wt% mPE (AFFINITY™ PL1280, The Dow Chemical Company), 5 wt% EAA copolymer (9.7 wt% acrylic acid content, PRIMACOR™1430, The Dow Chemical Company), and 5 wt% EAA copolymer (20 wt% acrylic acid content, PRIMACOR™5980i, The Dow Chemical Company); and C) 35 wt% copolyamide (PLATAMID™ HX 2585T, Atofina), 50 wt% mPE (AFFINITY™ PL1280, The Dow Chemical Company), 10 wt% EAA copolymer (9.7 wt% acrylic acid content, PRIMACOR™1430, The Dow Chemical Company), and 5 wt% EAA copolymer (20 wt% acrylic acid content, PRIMACOR™5980i, The Dow Chemical Company). Compositions A) through C) above are desirably extrusion coated at a thickness of 1.0 to 1.5 mil (25 to 38 μm) onto a spunbond polypropylene (SBPP) nonwoven sheet having a basis weight of 2.0 osy (67.8 gsm). The compositions may also be coated at a thickness of 1.0 to 2.0 mils (25 to 51 μm) onto a woven HDPE fabric made from oriented HDPE tapes, the fabric having a basis weight of 0.6 to 1.8 osy (20.3 to 61 gsm). Films formed from compositions A) through C) above may be incoφorated into a three-ply laminate. One laminate has outer layers of a 1.0 osy (33.9 gsm) SBPP non- woven fabric and a 1.0 osy (33.9 gsm) woven HDPE fabric and a center layer of a 1.5 mil (38 μm) film that is extrusion coated onto either outer layer before assembly. A second laminate has a core layer of a 2.0 osy (67.8 gsm) SBPP nonwoven sheet and outer layers of film A), B) or C) with a thickness of 1.0 mil (25 μm). Films formed from compositions A) through C) above may be used in varying thicknesses (for examle 4 to 6 mils (102 to 152 μm)) as an interior wall vapor retarder. Films formed from such compositions and having a thickness such as 2 to 6 mils (51 to 152 μm) may be laminated onto fiberglass batting to provide a second option for an interior wall vapor retarder. A 2-ply laminate comprising, for example, a 1 to 2 mil (25 to 51 μm) film formed from such compositions and a 1 osy (33.9 gsm) SBPP non-woven fabric may be laminated to fiberglass batting to provide a third option. The 2-ply laminate noted above may be laminated to an open-cell or closed-cell polymer foam (for example polyisocyanurate foam, extruded polystyrene foam, or extruded polypropylene foam) body to function as a moisture or water vapor permeable facer. The body may, for example, be a plank or a sheathing material such as would be used in building and construction applications for exterior sheathing on a frame wall. The following examples illustrate, but do not in any way limit the scope of the present invention. Material Description The following resins utilized in the film compositions are indicated as: CoPAl (PLATAMID™ HX2585T, a copolyamide block copolymer having a nominal polyamide block content of 54 wt% and a nominal polyethylene glycol (PEG) block content of 46 wt%, Atofina); CoPA2 (GPJLTEX™ 3G, a low M_n copolyamide with < 20 wt% PEG, a melting point (mpt) of 110-120°C and a density 1.07 g/cc, EMS Chemie; CoPA3 (GRTLTEX™ 1330A, a copolyamide with < 20 wt% PEG, a mpt of 128-138°C and a density of 1.06 g/cc, EMS Chemie); CoPA4 (MACROMELT™ 6239, a dimer fatty acid-based low M_n copolyamide with < 20wt% PEG, Henkel); mPEl (AFFINITY™ PFl 140, a mPE having a density of 0.896 g/cc and a MI of 1.6 g/10 min, The Dow Chemical Company); mPE2 (AFFINITY™ PL 1280, a metallocene-catalyzed polyethylene having a density of 0.900 g/cc and a MI of 6.0 g/10 min, The Dow Chemical Company); LLDPE (DOWLEX™ 2247, a LLDPE (ethylene-octene copolymer) having a density of 0.917 g/cc and a MI of 2.3 g/10 min, The Dow Chemical Company); EAA1 (PPJMACOR™ 1430, an EAA copolymer having an acrylic acid (AA) content of 9.7 wt%, a density of 0.938 g/cc, and a MI of 5.0 g/10 min, The Dow Chemical Company); EAA2 (PPJMACOR™ 59801, an EAA copolymer having an AA content of 20.5 wt%, a density of 0.96 g/cc, and a MI of 300 g/10 min, The Dow Chemical Company); EAA3 (PPJMACOR™ 3460, an EAA copolymer having an AA content of 9.7 wt%, a density of 0.96 g/cc, and a MI of 20 g/10 min, The Dow Chemical Company); EMA (an ethylene/methyl acrylate copolymer having a methyl acrylate (MA) content of 20 wt% and a MI of 8.0 g/10 min, and available from Atofina under the trade designation 20MA08); EEA (AMPLIFY™ EA DPD-6169NT, an ethylene/ethyl acrylate copolymer having an ethyl acrylate (EA) content of 18 wt%, a density of 0.93 g/cc and a MI of 6.0 g/10 min, The Dow Chemical Company); CXA1 (BYNEL™ CXA E-418, a maleic anhydride (MAH) grafted EVA copolymer having a nominal vinyl acetate (VA) content of 25 wt%, <1.0 wt% MAH, a density of 0.96 g/cc and a MI of 11 g/10 min, E. I. du Pont de Nemours and Company); FUS (FUSABOND™ MCI 90, a MAH grafted ethylene-vinyl acetate copolymer having a nominal VA content of 28 wt%, a MAH content of 0.8 wt%, a density of 0.96 g/cc and a MI of 16 g/10 min, E. I. du Pont de Nemours and Company); GMA (LOTADER™ AX8900, an ethylene/methyl acrylate/GMA teφolymer having a nominal MA content of 25 wt%, a nominal glycidyl methacrylate (GMA) content of 8 wt% GMA and a MI of 6.0 g/10 min, Atofina). All expressions of wt% in this paragraph are based on weight of the polymer to which they refer. Test Procedures Conduct resin MI testing according to ASTM D- 1238 (2.16 kg, 190°C) and report flow rates in grams/10 minutes (g/10 min). Determine resin density according to ASTM D-792 and is reported as grams/cubic centimeter (g/cm or g/cc). Perform film machine direction (MD) and transverse direction (TD) tensile strength and percent elongation tests according to ASTM D-882 and report test data as pounds/square inch (psi) (megapascals (MPa). Measure Elmendorf tear strength in film MD and TD according to ASTM D-1922 and report test data in grams/mil (g/mil) (grams/micrometer (g/μm )). Use one inch (in) wide sealed strips to measure adhesion heat seal strength according to ASTM F-88 and report the data in pounds/inch (lbs/in) (N/mm)). Conduct hot bar sealing of a film to a substrate using a heat seal temperature of 300°F (149°C), an application pressure of 40 psi (0.28MPa) and a heat seal time of 5.0 seconds. Conduct water vapor permeability testing according to ASTM E-96-00 using both the dry dish (desiccant) method and the wet dish (water filled) method. Report permeability "perms", wherein 1 perm = 7 g/m -day. The W/D ratio is the ratio of wet dish permeability over the dry dish permeability. Measure hydrostatic head or water column height pressure resistance measured according to American Association of Textile Chemists and Colorists (AATCC) method 127-1995 using a TEXTEST™ FX3000 (TexTest AG, Zurich, Switzerland) instrumented hydrostatic head tester using a 60 mbar/minute pressure rate increase. Report data is reported for water (H₂O) breakthrough pressure in millibars, where 1 mbar = 1 cm H₂O head. Perform water absoφtion weight gain testing by immersing a film or laminate in distilled water at a temperature of 72°F (22°C) for a period of 24 hours. Compare the weight after immersion with that before immersion and determine a percent weight gain (loss) based upon the difference between the two weights. Example (Ex) 1 and Comparative Examples (CE) A through C Produce monolayer films having a thickness of 2 mils (51 μm) from polymer blends shown in Table I using a conventional slot die cast film line. Convert the polymer blends to polymer melts using a 1 inch (in) (2.5 cm) diameter, 24:1 length to diameter (L/D) single screw extruder at ramped temperatures of 320 to 380°F (160 - 193°C) into a 10 in (25 cm) wide slot die operating at 380°F (193°C). Cast the polymer melts onto a rotating chill roll (70°F, 21°C) to form a film and wind the film into a roll. Using the procedures detailed above, test the films for water vapor permeance (WVP) (both dry dish and wet dish). Table I below summarizes both polymer composition and water vapor permeance data. Table I

The data in Table I demonstrate that a polymer blend (Ex 1) containing at least 40 wt% of a non-polar olefin polymer and a copolyamide block copolymer with at least 20 wt% hydrophilic blocks (herein PEG repeat units) provides a film with a dry dish WVP of more than 5 perms (35 g/m²-24 hr) as well as a W/D ratio of more than 3. The polymer blends that lack such a copolyamide block copolymer (CE A through CE C) all fail to attain such a dry dish WVP or W/D ratio. As noted above, UBC Standard 14-1 requires a minimum Dry Dish WVP of 5 perms (35 g/m²-24 hr). The film of Ex 1 meets that standard. Those of CE A through CE C do not. Ex 2-5 Using the procedure and apparatus of Ex 1, prepare 6 mil (152 μm) films, test them for Dry Dish WVP and Wet Dish WVP and report blend composition and test data in Table π. Table II

The data in Table II demonstrate that heavy gauge (6 mil (152 μm) versus 2 mil (51 μm) films made from a blend of 40 wt% of a copolyamide that contains hydrophilic moieties based on ethylene glycol, 40 wt% or 45 wt% of a nonpolar olefin polymer (LLDPE or a mPE) and 15% or 20% of a carboxylic acid modified ethylene copolymer also provide satisfactory results in terms of an E-96 dry dish permeability of at least 5.0 perm (35 g/m²- 24 hr) and a W/D ratio of greater than 2.0, preferably greater than 3.0, CE D through CE G Subject samples of four commercially available housewrap or weather resistant barrier materials to water vapor permeance testing as in Ex 1. Table HI below summarizes data from that testing. CE D is a spunbond HDPE nonwoven commercially available from E. I. du Pont de Nemours and Company under the trade designation TYVEK™. CE E is a nonwoven PP coated with a microporous polyethylene film commercially available from Reemay under the trade designation TYPAR™. CE F is a woven HDPE fabric coated on both sides with polyethylene, microperforated, and available commercially from Fabrene under the trade designation AIR-GARD™. CE G is a #15 asphalt saturated cellulosic felt. Table III

The commercial polymeric housewrap or weather resistant barrier products (CE D, CE E and CE F) all have an acceptable Dry Dish WVP in that it is above 5 perms (35 g/cm²- 24 hr), but minimal difference between Dry Dish WVP and Wet Dish WVP as reflected by a low W/D ratio (1.3, 1.2 and 1.1, respectively). The asphalt saturated felt, CE G, while it has an acceptable Dry Dish WVP, Wet Dish WVP and W/D ratio, remains a heavy material that is subject to the shortcomings noted above. Ex 6-7 And CE H-M Replicate Ex 1 to prepare 51 μm films from the blends shown in Table III A. Table

III A also includes Dry Dish WVP and Wet Dish WVP test data. The blends represent varying amounts of CoPAl, mPE2 and EAA 1. Table III B shows the composition and includes additional data from a water absoφtion weight testing and adhesion heat seal strength according to ASTM F-88 using a 3.0 mil (76 μm) monolayer HDPE film substrate and a 3.0 mil (76 μm) monolayer PP homopolymer film substrate. The two non-polar polyolefin film substrates simulate conventional woven and non-woven fabrics for adhesion testing.

Table fll A

Table III B

~ means not measured The data in Table HI A and Table HI B illustrate several key points. First, a limited composition range of copolyamide relative to non-polar olefin polymer yields both a minimum of 5 perms (35 g/m -24 hr) dry dish WVP and a W/D ratio of > 2 and preferably > 3. Second, certain compositions (CE H and CE I) fail to provide a desired minimum adhesion to substrates of at least 0.7 lb/in (0.12 N/mm). Ex 7 provides satisfactory results for all tested parameters and Ex 6 satisfies all parameters save for adhesion to PP and it approaches that parameter. It can be expected that a composition mid- way between Ex 6 and Ex 7 (for example 45 wt% CoPAl) would meet desired film adhesion criteria for both PP and HDPE. CE K through CE M have very acceptable levels of adhesion, but fail to deliver on the minimum Dry Dish WVP requirement of 5 perms (35 g/m²-24 hr) and W/D ratio. CE J provides the minmum dry dish WVP and, while not tested for adhesion properties, is expected to exhibit acceptable adhesion levels to both substrates based upon the acceptable adhesion of the two adjacent samples tested. CE J does not, however, have a W/D ratio of at least 2. Some building codes set a lower specification for a moisture vapor retarder film or laminate at 1 perm (7 g/m -24 hr). For those building codes, a broader range of compositions may be used. All samples with < 80% CoPAl exhibit a weight gain of 2 to 10% when subjected to water absoφtion weight gain testing. CE N-R Replicate Ex 6 to prepare 3 mil (51 μm) thick films from the blends shown in Table IV A. Table TV A also includes Dry Dish WVP and Wet Dish WVP test data. The blends represent varying amounts of CoPAl, mPE2 and EAA 1. Table IV B shows the composition and includes additional data from a water soak test and adhesion heat seal strength according to ASTM F-88 using a HDPE substrate and a PP substrate. Tables IV A and TV B also include data from Ex 7 above for puφoses of comparison. Table TV A

Table TV B

~ means not measured The data in Table TV A and Table TV B illustrate that polar polymer compositions other than that of CE P, while having acceptable water vapor permeability values, lack a desirable combination of good water vapor permeability values as well as adhesion to both HDPE and PP substrates in excess of 1 lb/in (175 N/m). Ex 8-12 and CE S- U Replicate Ex 1 to prepare a series of 1.8 mil (46 μm) films using a set amount of CoPAl and varying amounts of non-polar polyolefin (mPE2) and a set amount of varying compatibihzers. Table V A shows the compositions together with Dry Dish WVP, Wet Dish WVP, W/D ratio. Table V B shows the compositions together with various machine direction (MD) physical property testing (yield tensile (YT), ultimate tensile (UT) strength and Elmendorf tear (ET) strength data).

Table V A

means not measured Table V B

— means not measured The data in Tables V A and V B illustrate that film compositions made with carboxylic acid modified ethylene copolymer compatibilizer (EAA1, EAA2, EAA3) all exhibit a YT in excess of 2,000 psi (14 MPa). Ex 12, made with a preferred blend of two polymers with different AA contents exhibits markedly improved tensile strength relative to Ex 11 which uses a single EAA copolymer. Comparable compositions made with MAH- grafted or GMA-modified ethylene copolymers (CE S-U) exhibit significantly lower tensile strengths (both YT and UT) and do not meet minimum tensile properties required for the current application. As the films for CE S through CE U have an undesirably low ultimate tensile strength, they are not subjected to WVP testing. Ex 13-16 Extrusion coat one face of a 2.0 osy (68 gram/square meter (gsm)) SBPP nonwoven (B0026, PGI Nonwovens) with a single layer (ply) of a composition as shown in Table VI. Use a 1.25 inch (3.2 cm) extruder equipped with an 8 inch (20.3 cm) wide slot die with a die gap set at 18 mil (457 μm) for extrusion coating. The extruder operates at ramped temperatures of 320°F to 380°F (160°C to 193°C) and the die is set at 380°F (193°C). Combine extrudate from the slot die with the SBPP nonwoven in a 3-roll stack's nip roll section and then pass the combined extrudate/nonwoven over chilled rolls in the 3-roll stack before winding the chilled, combined extrudate/nonwoven into a roll. The three roll stack and winder operate at a line speed of 39-46 feet per minute (fpm) (11.8 - 14.0 meters per minute (mpm)). Table VI also shows Dry MVP and Wet MVP as well as W/D ratio and Hydrohead (HH). Table VI

The data in Table VI demonstrates that compositions of the present invention provide Dry Dish WVP values in excess of the UBC Standard 14-1 minimum of 5.0 perms (35 g/m²- 24 hr) even when coated onto a nonwoven substrate. Ex 15 is believed to have a bad data point relative to HH because it has a weakened die gauge line along its entire length. During hydrohead testing, water perforates the film of Ex 15 at this weakened site. Absent that weakened line, the HH data of Ex 15 should be comparable to, if not greater than, that of Ex 13-14 and 16. An attempt to peel the extrusion coating from the nonwovens results in destruction of the coating. In the absence of quantitative data, this represents sufficient adhesion, an adhesion clearly in excess of 0.7 lb/in (122 N/m). When subjected to dry tensile testing (ASTM D-882), the coated nonwovens of Ex 13 through Ex 16 all exhibit a MD ultimate tensile (UT) strength of > 20 lb/inch (3500 N/m) and a transverse direction (TD) UT strength of > 20 lb/inch (3500 N/m). This tensile property performance, as well as permeability and hydrohead performance, meets UBC Standard 14-1 and ICBO AC38) acceptance criteria for weather-resistive barriers. All laminates exhibit desirable differential permeability as indicated by a W/D ratio greater than 3.0. Ex 17-18 and CE V-W Use a Brabender twin-rotor plasticorder (also referred to as a "high intensity mixer") fitted with mixing bowl and operating at a temperature of 350°F (177°C) for a period of five minutes to melt compound 50 gram (g) aliquots of the polymer compositions shown in Table Vπ. Remove the melt compound from the bowl, cut it into small pieces and allow it to cool to ambient room temperature (nominally 25°C). Evaluate the cooled melt compound for MI according to ASTM D-1238 at (190°C and 2.16 kg piston mass). Measure molten polymer flow rate from the MI die orifice and record the measurements as grams per 10 minutes (g/10 min). Average three separate measurements to determine the value reported in Table VII. Determine the estimated logarithmic weighted average melt index (MI est) for each composition using the procedure detailed above, the measured melt index of CoPAl and the known melt index values of the various polyolefin resins (mPE2, EAA1, EAA2). Table VH

— means not determined The data in Table VII suggest that a low viscosity CoPA resin (CE V) has a MI that is sufficiently high to make it very difficult to fabricate into a film using conventional cast film extrusion or conventional extrusion coating processes. However, compatabilized blends of a low viscosity copolyamide resin (for example CoPA 1) with a non-polar polyolefin (for example mPE2 as in Ex 17 and Ex 18) exhibit MI values well within typical cast film and extrusion coating melt index ranges. A comparison of the measured MI with the MI est ♦ shows that the values fall within approximately 10% of each other and indicate that the logarithmic technique is an effective tool for screening compositions. Ex 19-21 Thermally laminate the film of Ex 1 to a woven HDPE fabric scrim produced from oriented HDPE tapes by Fabrene Inc., a division of PGI. Fabric AT AN is a 0.8 osy (27 gsm) basis weight scrim comprising 4.6 tapes per inch (1.8 tapes/cm) waφ by 2.5 tapes per inch (1 tape/cm) weft. Fabric ASSN is a more tightly woven 1.4 osy (48 gsm) basis weight scrim comprising 9.1 tapes/inch (3.5 tapes/cm) waφ by 3.3 tapes/inch weft(1.3 tapes/cm). The oriented HDPE tapes have a width of 2.5 mm when woven in the waφ or machine direction and 4 mm when woven in the weft or transverse direction. Two of the films also include a 1.0 osy (34 gsm) SBPP nonwoven (B0016, PGI Nonwovens). Use a Chemsultants Model HL-1000 benchtop hot roll laminator with an electrically heated 300°F (149°C) roll having a width of 18 in (45.7 cm) and a diameter of 4 in (10.2 cm) and a silicone rubber back up roll of a similar size and a line speed of 3 feet per minute (fpm) (0.9 meter per minute (mpm)) to prepare the laminates shown in Table VIII. Table VIII also records Dry MVP and Wet MVP as well as W/D ratio for the laminates. Table VIII

The laminates have sufficient bonding strength that an attempt to effect delamination destroys the laminate. Dry tensile testing as in Ex 13-16 shows that all three laminates 19-21 have both MD and TD UT strengths of more than 30 lb/in (5250 N/m ). As such they exceed both UBC Standard 14-1 and ICBO AC38 acceptance criteria for weather-resistive barriers. All laminates exhibit differential permeability as indicated by a W/D ratio greater than 3.0.

Claims

CLAIMS: 1. A film-forming polymer composition comprising a blend of at least forty percent by weight, based on blend weight, of a non-polar polyolefin or non-polar olefin copolymer, less than fifty percent by weight, based on blend weight, of a copolyamide block copolymer, and a compatibilizing amount of an unsaturated carboxylic acid-modified polyethylene or ethylene copolymer, the copolyamide block copolymer having polymerized therein polyamide blocks and hydrophilic blocks, the hydrophilic blocks being present in an amount of at least 20 percent by weight, based on block copolymer weight, and being polyethers having at least 50 percent by weight, based on polyether weight, of-(C2H4-O) — units polymerized therein.

2. The composition of Claim 1 , wherein the non-polar polyolefin or non-polar olefin copolymer is selected from linear low density polyethylene, low density polyethylene, high density polyethylene, a heterogeneous ethylene/α-olefin inteφolymer, a homogeneous ethylene/α-olefin inteφolymer, a substantially linear ethylene/α-olefin inteφolymer, a propylene/α-olefin inteφolymer, a polypropylene homopolymer, or a mixture of two or more of said polyolefins and copolymers; and the unsaturated carboxylic acid-modified polyethylene or ethylene copolymer is an ethylene/acrylic acid copolymer or an ethylene/methacrylic acid copolymer with an acid content of at least 6.5 percent by weight, based on copolymer weight.

3. The composition of Claim 1 , wherein the compatibilizing amount is within a range of from 5 to 25 percent by weight, based on composition weight.

4. The composition of Claim 1 , wherein the copolyamide block copolymer is present in an amount within a range of from 25 percent by weight to 45 percent by weight, based upon blend weight.

5. A polymeric film formed from the composition of Claim 1 , the film having a dry cup water vapor permeability of at least 1 perms (7 g/m²-24 hr) when tested according to ASTM E-96, and exhibiting a wet cup water vapor permeability to dry cup water vapor permeability (W/D) ratio of at least 2.0.

6. The film of Claim 5 wherein the non-polar polyolefin or the non-polar olefin copolymer is present with the copolyamide block copolymer as a co-continuous inteφenetrating network.

7. A fabric reinforced laminate comprising a substrate having applied thereto at least one ply of the film of any of Claim 5 or Claim 6, the substrate being a woven or nonwoven fabric comprising a non-polar olefin polymer, the olefin polymer being a homopolymer, a blend of two or more homopolymers, a copolymer, a blend of at least one homopolymer and at least one copolymer, or a blend of two or more copolymers, and having a first side and a second side, the film ply being applied to the first side or the second side or both the first side and the second side.

8. The laminate of Claim 7 wherein the laminate has a heat seal strength of film to substrate of at least 0.7 pound per inch (123 N/m) when subjected to a sealing temperature of 300°F (149°C) for a period of 5 seconds.

9. A coated fabric comprising a substrate having applied thereto a coating of the composition of any of Claims 1 through 4, the substrate being a woven or nonwoven fabric comprising a non-polar olefin polymer, the olefin polymer being a homopolymer, a blend of two or more homopolymers, a copolymer, a blend of at least one homopolymer and at least one copolymer, or a blend of two or more copolymers, and having a first side and a second side, the coating being applied to the first side or the second side or both the first side and the second side.

10. A fabricated article comprising the polymeric film of Claim 5, the fabric reinforced laminate of Claim 7 or the coated fabric of Claim 9, the article being a housewrap, a roofing underlayment, a crawlspace or foundation underlayment, an insulation batting facer, an interior wall vapor retarder, or a facer for a foamed insulation board or plank.