WO1995015354A1

WO1995015354A1 - Films produced by bubble formation of compositions of polyamide and functionalized polyolefin

Info

Publication number: WO1995015354A1
Application number: PCT/US1994/013657
Authority: WO
Inventors: Thomas Charles Long; William Walter Furrer; Carl Elliot Altman; Joseph Edgar Mackey; Henry Irvin Davis
Original assignee: Alliedsignal Inc.
Priority date: 1993-12-01
Filing date: 1994-11-29
Publication date: 1995-06-08
Also published as: EP0731821A1; JPH09506125A; JP3467745B2; CA2176576A1

Abstract

The present invention provides a film produced by forming a bubble from a composition comprising: (a) up to about 99.9 weight percent based on the total weight of the composition of a polyamide; and (b) at least about 0.1 weight percent based on the total weight of the composition of a polyolefin having functional groups which are reactive with the functional groups of the polyamide wherein the functional groups of the polyolefin are present in an amount sufficient to maintain the strength of the bubble. The film is particularly useful as a carrier film in the production of sandwich composites of sheet molding compound and thick molding compound.

Description

FILMS PRODUCED BY BUBBLE FORMATION OF COMPOSITIONS OF POLYAMIDE AND FUNCTIONALIZED

POLYOLEFIN

Background of the Invention

Field of the Invention

The present invention relates to polyamide-containing films produced by bubble formation of compositions which are useful, for example, as carrier webs in the production of composite materials.

Description of the Prior Art

A considerable amount of progress has been made in the technology of reinforcing plastics. Spurred mainly by the need of the automobile industry to produce Ughter weight, more energy-efficient automobiles, much of the activity in this field has been devoted to producing plastics with enough strength and durabiUty to replace many of the metal structural support members of the automobile body. The reinforced plastic part must exhibit similar structural strength and integrity as the metal component while simultaneously reducing its weight at equal, or preferably, lower cost. As a result, a large amount of activity in developing high strength structural composites has been devoted to utilizing sheet molding compound (SMC) and similar materials, which allows relatively fast matched-die molding methods. SMC is generally comprised of crosslinkable polymeric resin, particularly unsaturated polyester, styrene monomer (a cross-Unking agent), particulate filler, and chopped fiber reinforcement, as weU as various other additives in minor amounts. This composite material is usually prepared by depositing the chopped fiber on a layer of fluid resin supported on a moving polyamide film and then placing another layer of polyamide film (onto which another layer of fluid resin may have been deposited) on top to form a sandwiched composite which is passed through a series of kneading and compaction roUs and is usually wound into large roUs or festooned for storage. After a maturation period of about 2-5 days during which the material increases in viscosity to a moldable consistency, the SMC is used to produce molded parts for automobiles, boats, etc., by cutting a piece of appropriate size from the roU (or other structure), peeling away the polyamide carrier film(s), and placing the SMC in a heated mold for simultaneous molding and complete curing. Thus, SMC sandwich composites are used in compression molding procedures, and particularly in matched die molding operations. A similar material, thick molding compound (TMC), is prepared by a similar process and is used mostly in injection molding appUcations. Polyamide-containing films are useful in the production of SMC and TMC because polyamide is relatively impermeable to styrene monomer and provides good strength. Commonly assigned U.S. Patent 4,444,829 teaches that films formed from blends of polyamide and various polyclefins are exceUent carrier films for producing such sandwich composites. That patent discloses the production of such films by a casting process. The preferred product described in the patent (a blend of nylon 6 and ethylene vinyl acetate copolymer) has been extensively used in the industry with much success. Such film possesses exceUent strength, impermeabiUty to the styrene component of the SMC, and exceUent peelabiUty from the SMC material. Another cast film product that has been used is formed from a blend of nylon 6,6 and a modified polypropylene.

It is desirable to produce such film by a blown film process which results in better roU conformity. However, one problem facing the film production industry is the inabiUty to blow extrude films wherein the polyamide has a relatively low molecular weight (such as measured by a formic acid viscosity of less than about 120 for nylon 6). As those skiUed in the art know, blown film extrusion involves forcing a plasticized film composition through an annular die head and forming a film bubble which is ultimately coUapsed and formed into a film. See, for example, Modern Plastics Encyclopedia 1992, pages 245-248. It has been found that a blend of ethylene-vinyl acetate copolymer and polyamide 6 having a formic acid viscosity of less than about 120 could not be formed into a film by the blown extrusion process as a stable bubble was not formed. It would be desirable to provide a film produced by a blown film process for use, for example, in the manufacture of SMC and other composite materials, which utilized lower molecular weight polyamides and yet maintained the excellent strength, styrene impermeabiUty and peelabiUty from the composite compound of existing film

Summary of the Invention

The present invention, which responds to the aforedescribed problem facing the film production industry of the inabiUty to blow extrude films wherein the polyamide has a relatively low molecular weight (for nylon 6, a formic acid viscosity of less than about 120), provides a composition of polyamide with a minimal amount of a polyolefin having reactive groups which maintain the strength of the bubble during blown film extrusion.

Thus, the present invention provides a film produced by forming a bubble from a composition comprising: (a) up to about 99.9 weight percent based on the total weight of the composition of a polyamide; and (b) at least about 0.1 weight percent based on the total weight of the composition of a polyolefin having functional groups which are reactive with the functional groups of the polyamide wherein the functional groups of the polyolefin are present in an amount sufficient to maintain the strength of the bubble.

The present invention also provides a film produced by forming a bubble from a composition comprising: (a) up to about 99.9 weight percent based on the total weight of the composition of a polyamide; (b) at least about 0.1 weight percent based on the total weight of the composition of a polyolefin having functional groups which are reactive with the functional groups of the polyamide wherein the functional groups of the polyolefin are present in an amount of at least about 0.01 weight percent based on the total weight of the polyolefin, preferably from about 0.01 to about 10 weight percent based on the total weight of said polyolefin; and (c) about 5 to about 50 weight percent based on the total weight of the composition of an unfunctionalized polyolefin. The present invention also provides a process of forming a polyamide-contai ing film produced from a bubble. The improvement comprises forming the bubble from a composition comprising: (a) up to about 99.9 weight percent based on the total weight of the composition of a polyamide; and (b) at least about 0.1 weight percent based on the total weight of the composition of a polyolefin having functional groups which are reactive with the functional groups of the polyamide, wherein the functional groups of the polyolefin are present in an amount sufficient to maintain the strength of the bubble.

Detailed Description of the Preferred Embodiments

As discussed above, the film of this invention comprises a polyamide and a functionalized polyolefin, preferably also comprising an unfunctionalized polyolefin. Polyamides useful in the present invention are characterized by the presence of recurring carbonamide groups as an integral part of the polymer chain which are separated from one another by at least two carbon atoms, fllustrative of these polyamides are those having recurring monomeric units represented by the general formula:

-NHC(0)RC(0)NHRl- OΓ -NH-R-C(0>

or a combination thereof in which R and R* are the same or different and are alkylene groups of at least about two carbon atoms, preferably alkylene having from about 2 to about 12 carbon atoms. The polyamides of the present invention have relatively low molecular weights. The formic acid viscosity (FAV) of the polyamide is preferably from about 50 to about 120 (as measured by ASTM D-789). In this method, a solution of 11 grams of polyamide in 100 ml of 90% formic acid at 25°C is used. Exemplary of such polyamides are polyamides formed by the reaction of diamines and diacids such as poly(tetramethylene adipamide) (nylon 4,6); poly(hexamethylene adipamide) (nylon 6,6); polyhexamethylene azelaiamide (nylon 6,9); poly(hexamethylene sebacamide) (nylon 6,10); polyhexamethylene isophthaUmide (nylon 6,1); polyhexamethylene terephthalimide (nylon 6,T); poly(heptamethylene pimelamide) (nylon 7,7); poly(octamethylene suberamide) (nylon 8,8); poly(nonamethylene azelamide) (nylon 9,9); poly(decamethylene azelamide) (nylon 10,9); and the Uke. Also iUustrative of useful polyamides are those formed by polymerization of amino acids and derivatives thereof, as for example lactams. IUustrative of these useful polyamides are poly(4-aminobutyric acid) (nylon 4); poly(6- aminohexanoic acid), also known as poly(caprolactam) (nylon 6); poly(7- aminoheptanoic acid) (nylon 7); poly(8-aminooctanoic acid)(nylon 8); poly(9-aminononanoic acid) (nylon 9); poly(10-aminodecanoic acid) (nylon 10); poly(l l-aminoundecanoic acid) (nylon 11); poly(12- aminododecanoic acid) (nylon 12); and the Uke. Blends of two or more polyamides may also be employed.

Other polyamides that can be utilized are those resulting from adipic acid and meta-xylylene diamines (nylon MXDA); adipic acid, azelaic acid and 2,2-bis-(p-aminocyclohexyl)propane; terephthaUc acid and 4,4'-diamino-dicyclohexylmethane; and the like.

Copolymers formed from recurring units of the above referenced polyamides may also be used. By way of iUustration and not limitation, such polyamide copolymers include caprolactam/hexamethylene adipamide copolymer (nylon 6/6,6); hexamethylene adipamide/caprolactam copolymer (nylon 6,6/6); trimethylene adipamide/hexamethylene azelaiamide copolymer (nylon trimethyl 6,2/6,2); hexamethylene adipamide/ hexamethylene-azelaiamide/ caprolactam copolymer (nylon 6,6/6,9/6); and the like.

Preferred polyamides for use in the practice of this invention are poly(caprolactam) (nylon 6) and poly(hexamethylene adipamide) (nylon 6,6), and blends and copolymers thereof. The most preferred polyamide is poly(caprolactam).

Polyamides useful in the practice of this invention may be obtained from commercial sources or prepared in accordance with known preparatory techniques.

As mentioned above, the polyamides of this invention have relatively low molecular weight. The FAV of the polyamides ranges from about 20 to about 120, preferably from about 50 to about 120. This corresponds to a number average molecular weight of about 10,000 to about 35,000. Preferably, the molecular weight ranges from about 20,000 to about 30,000. The polyamide is present in an amount preferably of up to about 99.9 weight percent based on the total weight of the composition, more preferably about 50 to about 99.9 weight percent based on the total weight of the composition, and most preferably about 75 to about 99.9 weight percent based on the total weight of the composition.

The polyolefins used herein include polymers of alpha-olefin monomers having between about 2 and about 6 carbon atoms and includes homopolymers, copolymers (including graft copolymers), and terpolymers of alpha-olefins. IUustrative homopolymer examples include low, linear low, medium, or high density polyethylene; polypropylene; polybutylene; polybutene-1; poly-3-methylbutene-l; poly-pentene-1; poly-4-methylpentene-l; polyisobutylene; and polyhexene. IUustrative copolymer and terpolymer examples include copolymers and terpolymers of alpha-olefins with other olefins such as ethylene-propylene copolymers; ethylene-butene copolymers; ethylene-pentene copolymers; ethylene-hexene copolymers; and ethylene-propylene-diene copolymers (EPDM). The term polyolefin as used herein also includes acrylonitrile- butadiene-styrene (ABS) polymers. Preferred polyolefins are those prepared from alpha-olefins, most preferably ethylene polymers, copolymers, and terpolymers. The above polyolefins may be obtained by any known process. The polyolefin may have a molecular weight of about 1,000 to about 1,000,000, and preferably about 10,000 to about 500,000. Preferred polyolefins are polyethylene, polypropylene, polybutylene, and copolymers, and blends thereof. The polyolefins having functional groups useful herein are polyolefins which have functional groups which are reactive with the functional groups of the polyamide (which are amine and/or carboxyUc acid). Any functional group which wiU react with the fimctional groups of the polyamide may be used in the present invention. Preferred functional groups are selected from the group consisting of unsaturated polycarboxyUc acids and acid anhydrides thereof. The unsaturated polycarboxyUc acids and anhydrides include maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, and mixtures thereof. The more preferred functional group is anhydride and the most preferred functional group is maleic anhydride. The functional group may be suppUed by reacting the polyolefin with the functional group. The functional group may be grafted to the polyolefin by any known grafting process. Alternatively, the reactive moiety may be copolymerized into the backbone of the polyolefin. The polyolefin may include one or more types of functional groups.

Commercially available polyolefins having functional groups which are reactive with polyamide are preferably employed in the composition of this invention. The polyolefin having functional groups suitable for the present invention may also be produced in accordance with known processes, including but not limited to the processes described in U.S. Patents 3,481,910; 3,480,580; 4,612,155; and 4,751,270. In performing the graft-polymerization of unsaturated carboxyUc acid and anhydride to the polyolefin, various methods have been utilized for initiating the grafting polymerization process such as γ-ray, X-ray, or high-speed cathode ray irradiation processes, and a free radical initiator process. The reaction of the polyolefin with an unsaturated polycarboxyUc acid or an anhydride in the presence of a free radical (e.g., a peroxide) is the most widely used method of the grafting process. The method of using peroxide is advantageous since no special equipment or device is required for initiating the graft polymerization reaction. Examples of the peroxides employable include benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide and azo compounds, such as azo-bis (isobutyronitrile). U.S. Patent No. 4,612,155 discloses a grafting process employing such a radical initiator that obtains the grafting yield of 50-90% under favorable circumstances. U.S. Patent No. 4,751,270 discloses more specialized radical initiators that attain up to 100% grafting efficiency and improve grafting specificity of the functional moiety to polyolefins.

Graft polymerization reaction is generaUy performed by standard graft polymerization techniques known in the art, such as heating a mixture of a polyolefin, a monomer of the functional group, and a radical initiator, after mixing those or in mixing procedure, to a temperature at which the polyolefin becomes molten, under kneading of the mixture. Alternatively, the above-stated compounds are dissolved or suspended in an appropriate solvent to perform the graft polymerization reaction. The polyolefin having functional groups is present in an amount preferably of at least about 0.1 weight percent based on the total weight of the composition, more preferably about 0.1 to about 10 weight percent based on the total weight of the composition, and most preferably about 0.1 to about 1 weight percent based on the total weight of the composition.

It has been surprisingly found that the amount of functional groups present based on the total weight of the composition required to maintain the strength of the bubble formed during production of the blown film is minimal compared with the prior art teachings. (See for example U.S. Patents 5,010,136; 5,047,479; 5,064,700; 5,122,570; and 5,126,407.) The functional groups of the polyolefin are present in an amount sufficient to maintain the strength of the bubble formed during production of the film. The functional groups of the polyolefin are present in an amount preferably of about 0.01 to about 10 weight percent based on the total weight of the polyolefin, more preferably about 0.1 to about 5 weight percent based on the total weight of the polyolefin, and most preferably about 0.2 to about 1 weight percent based on the total weight of the polyolefin.-

Although not wishing to be bound by theory, it is beUeved that the functional groups of the polyolefin react with the functional groups on the polyamide. In other words, it is beUeved that the anhydride or acids groups of the polyolefin react with the amine groups on the polymeric chain ends of the polyamide. These reactions graft the polyamide to the polyolefin. It is beUeved that these reactions contribute to the bubble strength.

Unlike carboxyUc acids and anhydrides, esters on the polyolefin undergo minimal or no reaction with amine groups on the polymeric chain ends of the polyamide. It is believed that this explains why a bubble did not form when an attempt was made to blow extrude film from a blend of ethylene-vinyl acetate copolymer and polyamide 6. Thus, it is beUeved that compositions such as the blends of: polycarbonamide and ethylene- methyl acrylate copolymer taught by U.S. Patent 3,472,916 and polyamide and ethylene-methylacrylate-methacryUc acid taught by U.S. Patent 4,174,358 would not form a bubble.

Preferably, the present invention further comprises unfunctionaUzed polyolefin. The unfunctionaUzed polyolefins include those mentioned above which do not have the aforementioned functional groups attached thereto. These include polymers of alpha-olefin monomers having between about 2 and about 6 carbon atoms and includes homopolymers, copolymers (including graft copolymers), and terpolymers of alpha-olefins and unlike the above-described polyolefin having functional groups, the polyolefin does not have functional groups, i.e.. is unfunctionaUzed. Illustrative homopolymer examples include low, linear low, medium, or high density polyethylene; polypropylene; polybutylene; polybutene-1 ; poly-3-methylbutene-l; poly-pentene-1; poly-4-methylpentene-l; polyisobutylene; and polyhexene. Illustrative copolymer and terpolymer examples include copolymers and terpolymers of alpha-olefins with other olefins such as ethylene-propylene copolymers; ethylene-butene copolymers; ethylene-pentene copolymers; ethylene-hexene copolymers; and ethylene-propylene-diene copolymers (EPDM). The above polyolefins may be obtained by any known process. The polyolefin component may have a molecular weight of about 1,000 to about 1,000,000, and preferably about 10,000 to about 500,000. Preferred polyolefins are polyethylene, polypropylene, polybutylene, and copolymers, and blends thereof. The unfunctionaUzed polyolefin provides good release properties when the present film is used in the production of sandwich composites of SMC, TMC or other composite material, and are generaUy less expensive than the functionalized polyolefins. The unfunctionaUzed polyolefin is present in an amount preferably of about 5 to about 50 weight percent based on the total weight of the composition, more preferably about 5 to about 40 weight percent based on the total weight of the composition, and most preferably about 5 to about 25 weight percent based on the total weight of the composition. The film of the present invention may be prepared by thoroughly blending together the polyamide, polyolefin having functional groups, and unfunctionaUzed polyolefin if used, and optionaUy various minor amounts of conventionaUy used additives such as pigments, heat stabilizers, antistatic agents, and the like. Preferably, a pigment is used so that it can eastiy be determined that aU of the release film has been removed from the composite material. Such pigment may be present in any desired amount, such as from about 0.01 to about 2 weight percent of the composition, more preferably from about 0.1 to about 1.5 weight percent. As mentioned above, the film of this invention is formed by a bubble formation process. In this process, the film forming apparatus may be one which is referred to in the art as a "blown film" apparatus and includes an annular die head for bubble blown film through which the plasticized film composition is forced and formed into a film "bubble", which is ultimately collapsed and formed into a film.

The film of this invention may be of any thickness desired and includes those which have thicknesses typicaUy less than about 16 mils (400 μm). Preferably, the film has a thickness of from about 0.2 πul (5 μ m) to about 10 mils (250 μm); more preferably the film has a thickness of from about 0.4 mil (10 μm) to about 5 mils (130 μm), and most preferably the film has a thickness of from about 0.5 mil (12.5 μm) to about 2 mils (50 μm). While such thicknesses are preferred as providing a readUy flexible film, it is to be understood that other film thicknesses may be produced to satisfy a particular need and yet faU within the present invention's scope.

The films of this invention may optionaUy be stretched or oriented in any direction if so desired using methods known to those of skiU in the art. In such a stretching operation, the film may be stretched in either the direction coincident with the direction of movement of the blown film, also referred to in the art as the "machine direction", or in a direction which is perpendicular to the machine direction, and referred to in the art as the "transverse direction" where the resulting film is "uniaxiaUy" oriented, or in both the machine direction and the transverse direction, where the resulting film is "biaxiaUy" oriented. Such biaxiaUy orientation may be simultaneous or sequential. If the film is oriented after manufacture, the film typicaUy is drawn by passing it over a series of preheating and heating roUs. The heated film moves a set of nip roUs downstream at a faster rate than the film entering the nip roUs at an upstream location. The change of rate is compensated for by stretching in the film. Typical process and range of conditions for monoaxiaUy oriented polyamide films are disclosed, for example, in U.S. Patent No. 4,362,385. As noted above with respect to the use of pigment in the formulation, it is important in SMC, TMC and other composite manufacturing processes that the carrier film should also exhibit a peel adhesion or peelabiUty such that the film peels off easily from the composite material prior to molding with very little, if any, of the film adhered to the compound.

Typical SMC and TMC compound formulations are known in the art. For example, see the aforementioned commonly assigned U.S. Patent 4,444,829, the disclosure of which is expressly incorporated herein by reference.

The films of this invention offer a range of release properties suitable for use in various release film applications. The films are particularly applicable for the production of prepreg material forms and in the production of SMC, TMC as weU as bulk molding compound (BMC). The films are also particularly apphcable as a carrier web for the production of fiber reinforced panels (FRP). In each of these processes, a carrier film is used in the production procedure. The process for the production of SMC generaUy comprises casting a layer of heat-curable thermosetting resin, in fluid form, onto a continuously advancing film of the present invention; introducing reinforcing material onto the advancing fluid layer; contacting another layer of film (onto which there may have been deposited a layer of thermosetting resin) to the top surface of the reinforced fluid layer thereby forming a sandwiched composite; advancing the sandwiched composite through a series of kneading and compacting roUs; and winding or festooning the sandwiched composite for maturation.

The process for the production of TMC generaUy comprises impregnating discontinuous reinforcing fiber, i.e. desired lengths of chopped fiber, with resin paste; applying the impregnated fiber/resin composition to a moving carrier release film of the present invention; then applying a second release film of the present invention to sandwich the composition; then moving the sandwiched composition through a compaction area, thereby compacting the composition to form a sheet, generaUy much thicker then SMC; and then cutting the TMC sheet into desired lengths for packing. A process describing the production of TMC utilizing release films is disclosed, for example, in U.S. Patent 3,932,980. It can be seen that by this invention, it is possible to provide a blown film from relatively lower molecular weight polyamides. Such film retains the desirable physical properties mentioned earher, and is particularly useful as carrier webs in the production of SMC, TMC and similar composite materials.

The present invention is more fuUy iUustrated by the foUowing non- limiting Examples. COMPARATIVE EXAMPLE 1

A blend comprising 90% nylon 6 (71 FAV) and 10% ethylene vinyl acetate copolymer was extruded on a single screw extruder with a Maddox mixing head screw on a blown film extrusion line. The barrel and die temperatures were between 450 to 500°F (232-260°C); the die gap was between 0.020 and 0.040 inches. Film could not be successfuUy produced from this blend because a bubble could not be estabUshed.

In addition, blends of nylon 6 (70 FAV) and 10 to 20 weight percent of an unmodified polyolefin (linear low density copolymer of ethylene-butene described below) could not be used to produce film by the blown film process, again because a bubble could not be estabUshed. Moreover, under the above conditions, a blend of nylon 6 (130 FAV) and 20 weight percent of the same polyolefin copolymer likewise could not be used to produce film by this method because a bubble could not be estabUshed.

EXAMPLE 1

A blend of 90 weight percent nylon 6 (85 FAV) from AlUedSignal Inc., 0.5 weight percent of the maleic anhydride modified polyolefin described below and 9.5 weight percent of the unmodified polyolefin described below was extruded under the conditions of Comparative Example 1 above. Good bubble stabiUty was Jachied_/for bubbles at blow up ratios from 1.6 to 2.3, with film thicknesses of 0.0005 to 0.002 inch.

COMPARATIVE EXAMPLE 2 AND EXAMPLES 2 AND 3

Comparative Example 2 was a film formed from a composition of 90 weight percent nylon 6 (135 FAV) and 10 weight percent of ethylene- vinyl acetate copolymer. The film was formed by blown film extrusion.

Example 2 was a composition of 94 weight percent nylon 6 (85 FAV), 1 weight percent of maleic anhydride modified linear low density poly(ethylene-butene) copolymer (0.3 weight percent maleic anhydride, density of 0.904, melt index of 3.0), and 5 weight percent unmodified linear low density poly(ethylene-butene) copolymer (density of 0.900, melt index of 5.0). The film was formed by blown film extrusion as above.

Example 3 was a composition of 90 weight percent of the nylon 6 of Example 2, 1 weight percent of maleic anhydride modified polyolefin of Example 2, and 9 weight percent of the unmodified polyolefin of Example 2. The film was formed by blown film extrusion as above. The films were tested and had the foUowing properties. In the foUowing Table, COF means coefficient of friction. Where two values are indicated, the first value is in the machine direction and the second value is in the transverse direction:

The release properties of the present film were determined to be as good as the release properties of the comparative film. In addition, the styrene impermeabiUty and strength were also as good as the comparative film.

Claims

1 . A film produced by forming a bubble from a composition comprising:

(a) from about 50 to about 99.9 weight percent based on the total weight of said composition of a polyamide having a formic acid viscosity of less than about 1 20 as measured by ASTM D-789; and

(b) from about 0.1 to about 10 weight percent based on the total weight of said composition of a polyolefin having functional groups which are reactive with the amine or carboxylic acid groups of said polyamide, wherein said functional groups of said polyolefin are present in an amount of at least about 0.01 weight percent based on the total weight of said polyolefin.

2. The composition of claim 1 which further comprises: (c) about 5 to about 50 weight percent based on the total weight of said composition of an unfunctionaUzed polyolefin.

3. The film of claim 1 wherein the thickness of said film is about 5 to about 400 microns.

4. The film of claim 1 wherein said polyamide is selected from the group consisting of nylon 6; nylon 6,6; and blends and copolymers thereof.

5. The film of claim 1 wherein said polyamide is nylon 6.

6. The film of claim 1 wherein said polyamide is nylon 6,6.

7. The film of claim 1 wherein said polyamide has a formic acid viscosity of from about 50 to about 120.

8. The film of claim 1 wherein said polyolefin functional groups are present in an amount from about 0.01 to about 10 weight percent based on the total weight of said polyolefin. -

9. The film of claim 1 wherein said polyolefin is selected from the group consisting of low density polyethylene; linear low density polyethylene; medium density polyethylene; high density polyethylene; polypropylene; polybutylene; polybutene-1; poly-3- methylbutene-1 ; poly-pentene-1; poly-4-methylpentene-l; polyisobutylene; polyhexene; ethylene-propylene copolymers; ethylene-butene copolymers; ethylene-pentene copolymers; ethylene- hexene copolymers; ethylene-propylene-diene copolymers; and acrylonitrile-butadiene-styrene copolymers.

10. The film of claim 1 wherein said polyolefin in an ethylene polymer, copolymer, or terpolymer.