MXPA99008272A - Composite sheet material comprising polyamide film and fabric - Google Patents

Abstract

A composite sheet material comprising a polymeric polyamide film bonded to a fabric, the polymeric polyamide film being selected from films having a melting point of less than about 220°C and the fabric is selected from polyamides and polyesters. The composite sheet materials may be used in many different applications, for example tarpaulins, sails and parachutes, but most especially for use in airbags. A method for manufacturing the composite and an airbag structure, a method for making the airbag structure and a method for recovering the composite sheet materials for recycling purposes. There is also described a method for selecting the formulation of a multiphase polymer system so as to produce films having particular laminating properties.

Description

COMPOSITE SHEET MATERIAL COMPRISING FILM AND POLYAMIDE FABRIC FIELD OF THE INVENTION The present invention relates to composite sheet materials for use in many different applications, for example waterproof tarpaulins, sailcloth and parachutes, but more especially for use in airbags.

Also disclosed is a method for making the composite structure and an air bag, a method for making the structure of the air bag and a method for recovering the composite sheet materials for recycling purposes. Finally, a method for selecting the formulation of a multiphase polymer system to produce films having particular lamination properties is also described.

BACKGROUND OF THE INVENTION AND RELATED PREVIOUS ART Airbag systems are safety devices in motor vehicles, which have been shown to greatly reduce the risk of injury or death in REF: 31189 vehicle accidents, particularly collisions. A critical component of the airbag system is the fabric of the airbag, the material that is inflated and contains the occupant from hitting the interior of the car during an accident.

The fabric is usually a coated fabric. The fabric is typically woven of high tenacity nylon or polyester fibers with sufficient strength to withstand the internal pressures associated with deployment, which reaches approximately 9 to 12 psi of impact of the occupant in the bag, within the short duration of less of 100 milliseconds.

The coating of the fabric seals the fabric against the gas outlet, particularly at the seams (reducing that is prone to combing), the overall permeability of the fabric becomes more predictable and the coating can improve the productivity of cutting and stitching of the structure. The coating is typically a synthetic rubber such as polychloroprene or silicone rubber.

All publications and patents referenced herein are incorporated herein by reference. The practice established with the introduction of coated airbags in the North American coating market with grades of neoprene, a chloroprene elastomer, gave the way for the use of polymeric silicones, which were crosslinked by peroxides and applied with the help of a solvent. A coating of fabric intended for the materials used to build the air bags, involves organopolysiloxane products, unvulcanized thermosets, applied with an organic solvent, represents a recent advance in silicone technology (US patent 5,208,097, granted to Dow Corning Toray Silicone CO. LTD).

The use of silicone for the coating of fabrics is well established in a variety of applications: it is reported the largest market that is the coating of the fabric of the air bags (* L 'enduct ion qui rend 1' airbag plus reliable - The coating which makes airbags secure ", Fabrice Bohin, TUT, 1st Quarter 1997, No. 23) This article describes the trend towards the use of silicone compounds, which do not require the use of solvents during the coating process.

It is claimed to be designed specifically to establish the evolution of the airbag market, these compounds are said to offer the rheological properties that allow coatings, in general, to vary in thickness between 40 and 100 micrometers, which provides thermal protection improved on silicone coatings applied through the use of solvents.

The strong adhesion between the polymeric silicone layer and the fabric substrate is attributed to the covalent bond between the chemical groups of the silicone polymer and the reactive species on the surface of the fabric. This link is said to create a compound, which is "perfectly homogeneous." Two methods are proposed for compound recycling: incineration or re-extrusion with virgin polyamide 6,6 material to form articles with properties comparable to those of polypropylene.

It is the race of Reeves International Automotive Airbag Group (RIAAG), after much discussion with the assemblers of the airbag module that the ideal material for an airbag is actually an uncoated fabric that is like a coated cloth. The response of the Reeves Group to the challenge of designing a structure, which combines the positive attributes in both manifestations of the airbag fabric, has been developed with a material classified as 'hybrid coated / uncoated air bag' (A New Generation of Innovative Textile Substrates for Automotive Airbag, "Richard C. Kerr, paper presented at an Automotive Industry Materials Symposium, October 24, 1996).

US Patent 5,486,210 assigned to Reeves Brothers Inc. covers the chemistry in which the covalent chemical bonding occurs between two dissimilar polymers comprising the coating materials and the substrate is affected by the insertion technology. Its applied form is a composite product (Reevair®, a registered trademark of Reeves Brothers, Inc. Reg. No. 1,949,316) of a fabric substrate and a chemically introduced urethane / acrylic copolymer. The claimed advantage over the use of silicon based chemistry is expensive.

The compounds of the film layers on cloth substrates, with and without the use of adhesive layers, have been proposed as an alternative to the method of creating a system based on chemically bonded silicone, which is an integral part of the structure of the airbag. Constructions of the air bag using such compounds are claimed in US Patent Nos. 5,302,432 by Shigeta et al.

The material of US Patent No. 5,302,432 is comprised of a non-woven synthetic fiber fabric, for such a portion of the bag that will come into contact with the occupant, a woven synthetic fiber fabric that the inner face of the bag, and a film of a polyolefin resin licked between the fabric layers. It is contemplated that the outer layer, which is of non-woven fabric, will present a smooth surface for the occupant, while the inner fabric is intended to provide the required strength and barrier for the penetration of the substrate by the hot gases. The layer of the film between the layers of fabric, which is contemplated to prevent the gas from escaping, could be applied with or without the use of adhesives. The material of the film layer could be selected from high density polyethylene resin, low density polyethylene, polypropylene resin, ethylene vinyl acetate copolymer resin and ethylene vinyl acetate copolymer resin. Alternatively the layers of the film could be bonded with adhesives and examples of such structures are found in US Patent No. 4,963,412 by Kokeguchi in addition to the Breed patent.

As an invention generally related to coated fabrics, but directed more particularly to impart the characteristics of low permeability to fabrics for use in automotive repairs, without resorting to neoprene or silicone materials, it is awarded to Milliken Research Corporation in EP 0 761 868 A2. An integral structure is obtained by melting a thermoplastic material (such as polyamides, polyesters, polyolefins, thermoplastic polyurethanes) which is applied to the fabric as a light powder coating.

Having a melting point of at least 70 degrees below the melting point of the material comprising the fabric, the thermoplastic powder material undergoes rapid melting. The low melt viscosity helps the preferential arrangement of the coating material in the voids of a woven fabric. The controlled application of a powder ensures a light coating weight of less than one ounce per square yard of the fabric substrate, while still producing a fabric of very low permeability.

In the choice to apply a low melt polyamide to a polyamide fabric substrate, whereby a compound is essentially created from one type of polymer system, recycling of the material comprising the structure will be facilitated. This advantage has been cited in the creation of well-bonded composite consisting of reinforced polyester and low melt polyester matrix fibers to protect marine textiles and clothing (for example), for which a patent was granted to Hoechst Trevira GmbH & Co. KG (EP-768406-A1; DE 19537703-A1).

The silicone coating of the fabrics has a clear advantage over the use of neoprene to create the materials of the air bag, in which it is possible to achieve or improve upon the requirements of the specification a significantly reduced weight. The attack of chlorine on the fabric substrate, through the fragilization of the fibers comprising the fabric, has a detrimental effect on the properties of the composite structure with time. While the neoprene itself is prone to embrittlement when exposed to the effects of thermal aging, silicone compounds are characterized by a high degree of environmental stability. Silicone coated fabrics exhibit improved retention of properties in aging tests compared to neoprene coated fabrics.

Despite the advances made in silicone technology, two aspects remain: the coating operation adds costs and the coated fabrics can not be recycled effectively.

The formation of a chemically bonded system mitigates against the possibility of recovering the coating layer and the substrate, separating them. Separation is required to create the possibility of achieving the longest form of recycling, in which there is little emphasis on the recycling of products of diminished value, or on incineration with energy recovery.

Despite the claims made of nylon coated silicone fabric, when cut and heated, '... can be dispersed as with inorganic fillers, providing a different but sometimes advantageous profile of the mechanical properties for' reprocessed nylon ' (* Evolution of airbag components and materials ", Automotive Enginnering, February 1994, pp. 99-103), it is known that the presence of even smaller amounts of silicone in the reprocessed nylon has detrimental effects on the mechanical properties. Even when 'state of the art' employs hardening technology, the presence of silicone in small amounts reduces the impact resistance of substantially molded articles.

The same question could be expressed with respect to the recycling of airbag materials constructed by the chemical insertion of the urethane / acrylic copolymer system into a cloth substrate, as by the art of Reeves Brothers. In addition, the application of the treatment to the substrate increases the aspects of environmental impact. The complex chemistry is used to achieve the compound, which involves fiber treatments or fabrics with aqueous insertion solutions containing metallic ionic insertion initiators (silver salts are especially preferred), catalysts (such as peroxides) to activate or regenerate insertion primers and water dispersible polymers.

The use of low melting polymers to create integral structures of compounds with high melting as o. unlike the components suffers disadvantages. The application is limited to inflation with low temperature gases and the penetration of the low melting material in the holes of the cloth substrate has the effect of stiffening the structure. It should be recognized that a real laminate, p. ex. one that produces a bond between the layers of the laminate as opposed to a structure where the film penetrates the structure of the fabric substrate is the most desired of the possible laminates, as it constitutes the most easily recyclable structure.

The proposed materials of the film layer of the laminated structure claimed by Shi ga t a e t a l. , have significantly lower melting points than the materials of the inner and outer fabric layers of the structure, they are likely to penetrate the gaps of the fabric layers, thereby mitigating the advantage contemplated for using an outer layer not woven for the purpose of presenting a smooth exterior surface of the airbag by the occupant due to the arrangement. Having to choose the low melting materials for the film layer, it becomes necessary to weave tightly the inner fabric of a heat-resistant material, to protect the structure from penetration by hot inflation gases. The advantage of using a film layer for controlling the permeability of the structure is lost to allow the fabric of the structure to be lightly woven. And in the preferred embodiment of the patent, the adhesives are contemplated, and the treatment of the surfaces of the fabric layers to assist the adhesive is contemplated.

Where the use of adhesives is proposed to achieve strong bonding in laminations of film and fabric, the penalties associated with chemically bonded systems and those associated with integral structures are incurred.

There are generic requirements associated with flexible composite structures for applications in the range of (eg,) clothing and architectural fabrics for protection systems such as airbags. These include: a) it is ambient, especially at extreme temperatures; b) a balance of resistance and flexibility; c) permeability control; d) formability; e) low environmental impacts in the training stages (the stages are carried out in what is frequently referred to as the Value Added Chain (VAC) of the oil industry (for example) through the client in the form of the final product; f) reclassification; g) cost and h) design flexibility.

The requirements that pertain specifically to the use of flexible composite structures for airbags are clearly expressed in the standards that govern the qualification of materials. These are intended to ensure the safety of the occupant of the vehicle of an adult driver placed near the front of a steering wheel or a passenger predictably placed on the front of the instrument panel.

The attributes of a material for the use of the airbag should be considered with respect to the very high stress rates associated with rapid efficient use. It is also critical that the fabricated structure of the airbag material, once properly disposed, deflates properly in time and space. Consideration should also be given to how the supplementary restraint device can protect an occupant out of a lightweight position that sits somewhere in the vehicle, not necessarily secured by a seatbelt.

With the evolution in the inflation gas system to be used appropriately in the airbag, the flexibility to be able to select the construction materials, and the structure formed of these materials has assumed importance. Beyond the need to design safe and effective adequate use through systems based on sodium azide, where occupant protection of hot particulates is a critical consideration, there is now a need and opportunity to specify the materials of the air bag for operation with gases at low temperature, or with cleaning propellants that produce gases hotter than those associated with the azide generator.

With cost as an important consideration in the chains of value addition, in general, and particularly in the case of the automotive industry, it is highly desirable to be able to select the materials in a way that the opportunity can be taken to effect the efficiencies of production when the development requirements are not rigorous or to 'choose' the properties of the materials when the application demands high performance.

With the growth in the emphasis that is placed due to the effective and efficient recycling of the materials throughout the life cycle of the product they constitute, it is important to be able to "design" in the attributes of recycling of the materials.

Until now, it has not been possible to enjoy the ability to design composite, flexible sheet materials to meet the practical requirements cited above.

BRIEF DESCRIPTION OF THE INVENTION The present invention seeks to provide a sheet material composed of film and cloth that is lightweight and flexible, yet has the strength that will overcome the strong forces that arise when an airbag is inflated. A particularly important feature of the composite sheet material of this invention is that after use, it can undergo a mechanical recovery process that does not cause cross contamination of the film and the fabric and hence the air bag made of the material of the present composite sheet meets the requirements of recycling.

The composite sheet material of the present invention allows the requirements of a material of the air bag to be advantageously satisfied. However, the material of this invention is suitable for use in a range of applications, for example waterproof tarpaulins, sailcloths and parachutes. While these utilities are not described in detail, their implementation will be apparent from this description.

In its dest aspect, the present invention provides a composite sheet material comprising a polymeric polyamide film bonded to a fabric, the polymeric polyamide film being selected from films having a melting point of less than about Z20 ° C. and the fabric is selected from polyamides and polyesters.

Preferably the polyamide has at least some adjacent amide bonds along its polymer structure, at least one pendant alkyl branch, at least one sequence of at least seven consecutive carbon atoms and a melting point at the range from about 100 ° C to about 200 ° C. The polymeric polyamide film could comprise a monolayer film of a mixture of polyamides, a multilayer film of polyamides or a caextruded film of polyamides.

The polymeric polyamide film could be selected from polyamide films having a melting point of less than 200 ° C and a degree of crystallinity lower than that of nylon 66.

In another aspect of this d form of the invention, the polyamide could be prepared from (a) at least one dicarboxylic acid and at least one diamine wherein at least one dicarboxylic acid and / or at least one diamine contains at least one alkyl branching pendant having one to three carbon atoms, and wherein at least one dicarboxylic acid and / or at least one diamine have the sequence of at least seven methylene groups; (b) at least one alpha, omega aminocarboxylic acid, having the formula of H 2 N-R 1 -COOH, wherein R 1 is an aliphatic radical having at least seven methylene groups in sequence and a pendant alkyl branch having one to three carbon atoms; (c) at least one diamine and at least one nitrile selected from the group consisting of alpha nitriles, omega-amino alkylene and alpha omega alkylene dinitriles, wherein the diamine, nitrile and / or dinitrile contain at least one branching pendant alkyl having from one to three carbon atoms; and wherein the diamine, nitrile and / or dinitrile comprise at least seven methylene groups; or (d) mixtures of any of the monomers described in (a) - (c) above.

The other monomers that could be used to prepare the polyamide of the present invention are selected from aromatic dicarboxylic acids, aromatic diamines, alicyclic dicarboxylic acids and alicyclic diamines. The aromatic dicarboxylic acids could be selected from terephthalic acid and isophthalic acids, the alicyclic dicarboxylic acid is 1,4-bi-sme-cyclohexyl dicarboxylic acid, and the alicyclic diamine is 1,4-bismet-ilen-diamino-cyclohexane.

The material of the composite sheet could comprise a polymeric film based on copolymers and terpolymers of hexamethylene diamine, 2-met i lpent amethylendamine, adipic acid, dodecanedioic acid and epsilon-caprolactam (nylon 6).

The present invention provides in yet another main aspect, a composite sheet material consisting of a fabric substrate laminated to a polymeric film layer, wherein the film layer is formed of a multiphase polymer system comprising at least one linear aliphatic polyamide resin (PA-I), having a temperature range of narrow melting point, a melting point in excess of 200 ° C and a molecular weight of at least 5000; at least one polyamide resin (PA-II) comprising at least one pendant alkyl branch having from 1 to 3 carbon atoms within at least two amide bonds along the polymer structure and at least one sequence of at least seven consecutive carbon atoms, excluding the carbon atoms in the pendant alkyl branches, if any, within at least two amide bonds along the polymer structure, the melting point of the polyamide is lower of 200 ° C; Y at least one component (f-PO) comprising at least one of: an ethylene copolymer, E / X / Y, wherein E is ethylene and at least 50% by weight of E / X / Y, X is 1-35% by weight of an acid containing the unsaturated monocarboxylic acid, and Y is 0-49% by weight of a radical derived from 'at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms, and wherein further the acid groups in the acid-containing radical are neutralized from 0-100% by weight of a metal ion; a polymeric insertion agent containing the reactive groups selected from at least one of epoxides, isocyanates, aziridines, silanes, alkyl halides, alpha-halo ketones and aldehydes or oxazoline, which reacts with the acid-containing radicals in component i) and further reacts with the insertion sites of the components (PA-1) and (PA-II), and the weight percent of the monomer (s) containing the reactive groups is 0.5-15 weight percent of the polymeric insertion agent , and the remainder of the polymeric insertion agent contains at least 50% by weight of ethylene and 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide , sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms; Y at least one C2-C20 polyolefin selected from polyethylene, polypropylene, ethylene propylene diene terpolymer, copolymers of ethylene with vinyl acetate, carbon monoxide or ethylenically unsaturated carboxylic acids or esters thereof on which are inserted about 0.05 to about 5% by weight of the monomers or mixtures of monomers selected from ethylenically unsaturated acid monomers or their derivatives including acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, 5-norboren-2, 3- acid dicarboxylic, maleic anhydride, monomethyl fumarate and monomethyl maleate; and ethylenically unsaturated monomers containing the amino or hydroxy functional groups including vinyl pyridines, vinyl silanes, 4-vinyl pyridine, vinyl triethyloxy tin and allyl alcohol; wherein the composition of the polymer system comprising the film layer is characterized by the function: f (c) =. { [PA-I] + [f-PO]} /. { [PA-II] + [f-PO]} ([PA-I] + [PA-II] + [f-PO] = 1) where f (c) is a Composition Parameter; [PA-I] is the concentration of polyamide in% (w / w) (PA-I); [PA-II] is the concentration of polyamide in% (w / w) (PA-II); and [f-PO] is the concentration in% (w / w) of (f-PO), and f (c) has the values in the range of approximately 0.5 to approximately 2.0; wherein the numerator mainly determines the properties of the thermal barrier of the film and the denominator determines mainly the temperature for laminating the film layer to the fabric substrate.

In its most basic form, the present invention provides a multi-layer composite sheet material comprising at least one polymeric film bonded to at least one layer of fabric, wherein the layer of the polymeric film is formed of the multi-phase polymer systems , which are extracted from a continuum of formulations comprised of two categories of polyamides, and at least one of a category of the components described below as functionalized polyolefins.

The present invention provides a fabric for an automotive airbag material made of filaments of yarns of a polyamide or a polyester. A film layer is formed, or film layers are formed, by conventional means such as cast molding, extrusion coating on the fabric, blowing or orientation of the selected multiphase polymer formulations to establish the requirements of a bag application. of given air. A laminated composite structure is formed with the help of the previously established algorithm.

The algorithm established above creates the Parameter of Composition that has as its numerator the simple algebraic sum of the compositions of the components of the polymer formulation, which mainly determines the properties of the thermal barrier of the film. The said Parameter of Composition has as its denominator the simple algebraic sum of the compositions of the components, which mainly govern the temperature of lamination of the film layer to the fabric substrate.

The Composition Parameter now makes it possible to predict the properties of the resulting film and hence many aspects of the composite sheet material are controlled which therefore ensures that it is capable of satisfying the requirements of the applications for which it is manufactured.

Therefore in another aspect, this invention provides a method for selecting the characteristics of a film for use in a composite sheet material formed of film and fabric, and the film is formed of the multiphase polymer system defined above according to the function : F (c) =. { [PA-Ij + [f-PO]} /. { [PA-II] + [f-PO]} ([PA-I] + [PA-II] + [f-PO] = 1) where f (c) = Composition Parameter; [PA- 1] = concentation of polyamide (PA-I); [PA- I I] = concentration of polyamide (PA-II); and [f-PO] = concentration of (f-PO), and f (c) has values in the range of about 0.5 to about 2.0; and the numerator mainly determines the properties of the thermal barrier of the film and the denominator mainly determines the temperature for laminating the film layer to the fabric substrate. In all the examples it should be noted that the terms used in the previous and subsequent function, the units are% (p / p).

In a more significant aspect of the present invention, the lamination of the film layer or layers to the fabric substrate is effected without the use of an adhesive layer between the contact surfaces of the film and the fabric. In the making of the film and after the composite material, the value of the Composition Parameter is computed, associated with a given formulation from which the layer of the film in contact with the surface of the fabric substrate is formed. A simple monotonic increase ratio between the temperature, at which a strongly bonded laminate is formed, and the Composition Parameter allows the lamination temperature to be computerized. At temperatures much lower than the computerized value, only the weak thermal bond between the contact film and the fabric substrate is achieved. At a temperature much higher than the computerized value, an integral bonded structure is formed, which is characterized by the material of the contact film layer having the holes in the cloth substrate penetrated.

In still another aspect of the present invention, there is provided a method for recovering the components of a composite sheet material wherein the material could be delaminated mechanically using the thermal means, if necessary and substantially without cross-contamination of the components.

In another embodiment of the process recovery of the materials, a method is provided for recovering the components of a composite sheet material from the air bag comprising disassembling the material from its inflation module, when required; deconstruct the structure of the airbag, as needed; subjecting the material to a mechanical desalination process, which optionally includes thermal delamination means; and recover the components of the film and the fabric without their cross-contamination of the same for recycling.

The composite sheet of the present invention is composed of a film layer, wherein the first component of the film layer is at least one linear aliphatic polyamide (hereinafter referred to as (PA-I) having a temperature range of the narrow fusion, a melting point in excess of 200 ° C, and has a molecular weight of at least 5000.

The first component (PA-I) of the tertiary multiphase polymer system comprising the film layer is used in conjunction with a second component (hereinafter referred to as PA-II), which is at least one polyamide resin comprising at least one a pendant alkyl branch of 1 to 3 carbon atoms within at least two amide bonds along the polymer structure and at least one sequence of at least seven consecutive carbon atoms, excluding the carbon atoms in the branches alkyl pendants, if any, within at least two amide bonds along the polymer structure, the melting point of the polyamide which is less than 200 ° C.

In one embodiment, the first component and the second component of the tertiary multiphase polymer system comprising the film layer are used in conjunction with a third component (referred to later as f-PO), which is at least of: (i) an ethylene copolymer, E / X / Y, wherein E is ethylene and is at least 50% by weight of E / X / Y, X is 1-35% by weight of an acid containing acid unsaturated monocarboxylic acid, and Y is 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms, and wherein in addition the acid groups in the acid-containing radical are neutralized from 0-100% by weight of a metal ion; (ii) a polymeric insertion agent containing the reactive groups selected from at least one of epoxides, isocyanates, aziridines, silanes, alkyl halides, alpha-halo ketones and aldehydes or oxazoline, which reacts with the acid-containing radicals in the component i) and reacts additionally with the insertion sites of the components (PA-I) and (PA-II), and the weight percent of the monomer (s) containing the reactive groups is 0.5-15 percent by weight of the agent of polymeric insertion, and the remainder of the polymeric insertion agent contains at least 50% by weight of ethylene and 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, monoxide carbon, sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms; Y at least one C2-C20 polyolefin selected from polyethylene, polypropylene, ethylene propylene diene terpolymer, copolymers of ethylene with vinyl acetate, carbon monoxide or ethylenically unsaturated carboxylic acids or esters thereof to which about 0.05 are inserted. to about 5% by weight of monomers or mixtures of monomers selected from ethylenically unsaturated acid monomers or their derivatives including acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, 5-norboren-2, acid -dicarboxylic acid, maleic anhydride, monomethyl fumarate and monomethyl maleate; and ethylenically unsaturated monomers containing the amino or hydroxy functional groups including vinyl pyridines, vinyl silanes, 4-vinyl pyridine, vinyl tri eti loxy silane and allyl alcohol.

The first component (PA-I) could be a homo-polyamide ABAB, in particular, polycaproamide, known familiarly as nylon 6, or a homo-polyamide AABB, in particular, po 1 ihex ame ti 1 enadip ami da, familiarly known as nylon 6,6. Polyamides in the category (PA-I) are known to be easily formed in polycondensation processes, either as homo or copolymers and can be easily formed by extrusion and molding processes in thermoplastic articles, which possess good strength and hardness and strength to abrasion. The articles include movies.

The second component (PA-II) could be an ABAB homo-polymer of 2-me t i lpent ame t ilendi amine and dodecandioic acid. Polyamides in the category (PA-II) are known to be easily formed in polycondensation processes, either as homo or copolymers and can be easily formed by extrusion and molding processes in thermoplastic articles having good strength and rigidity, abrasiveness and resistance to abrasion. The articles include movies.

The third component (f-PO) is a category of ingredients comprised of at least one of (i) ethylene copolymers classified as ionomers; (ii) compatibilizers; and (iii) insertion polyolefins. The ingredient (i) of the category (f-PO) is exemplified by the Surlyn® type polymers, the most preferred form for use in the compositions of the present invention are the ethylene / methacrylic acid, ethylene / acrylic acid copolymers , ethylene / methyl acrylate / n-butyl acrylate and ethylene / methacrylic acid / methyl acrylate terpolymers: Surlyn® neutralized with zinc is preferred for nylon over Surlyn® neutralized with sodium. Some or all of component (i) could be replaced by component (iii).

The polyamides of the category (PA-I) could be melt-blended by conventional means with the polyamides of the category (PA-II), at least up to the preferred proportion of about 30% by weight of (PA-I) of the tertiary formulation. In general, each component could comprise about 10% to about 90% by weight of the mixture and more preferably, the mixture could be a 50:50 formulation. The binary phase materials thus formed can be easily extruded and molded into thermoplastic articles that exhibit a useful balance of strength and stiffness and adhesiveness. The articles include films that are characterized by the thermal properties between those associated with the respective polyamides that form, the blends.

In another aspect of the invention, the polyamides of the category (PA-I) could be melted by conventional means with the ingredients belonging to the category (f-PO), and the materials of the binary phase thus formed can be extruded and easily molded into thermoplastic articles that exhibit a unique balance of flexibility, hardness, chemical resistance and end-use temperature performance.

These mixture formulations are exemplified by the material known as ZYTEL FN®, a registered trademark of E.l. DuPont de Nemours Inc. In this mixture, the components (PA-I) and (f-PO) could comprise from 10% to about 90% by weight. In the mixture the components (PA-I) and the (f-PO) are preferably approximately in equivalent proportions.

It is known that melted blends of the category (PA-II) with the ingredients of the category (f-PO) can be easily extruded into films appropriate for packaging applications.

Films formed from tertiary multiphase polymer systems, formed by melt mixing of approximately equal quantities of the three categories of materials (PA-I), (PA-II) and (f-PO) by conventional means balance the useful properties of the respective binary combinations: (PA-I) with (f-PO); and, (PA-II) with (f-PO). These formulations are easily extruded into film form for use in the laminated laminated structures, as set forth in US Patent Application No. 60 / 014,150 published March 25, 1996 in the name of N. Farkas, expositions of the which are incorporated herein by reference.

Thus the present invention provides a polymeric film bonded to a fabric using conventional technology. The film itself is self-adhesive: an additional layer of an adhesive material is not required to effect the bonding. Furthermore, the temperatures required in the rolling step are significantly lower than the melting point of the fabric yarn so that the mechanical properties of the fabric are not significantly reduced by the rolling process.

Composite materials have been employed in the art of air bags due to the commencement of neoprene as an elastomeric cloth coating. The silicone coating has provided the advantages over the neoprene coating, and there have been advances in the art of silicone coating. A 'hybrid' structure has recently been introduced, which depends on the chemical bonding of a coating material to the substrate structure, such as an alternative non-silicone coating.The present film and composite fabric structures, which exhibit strong thermomechanical bond, now offer advantages over the hybrid structure.

The composite sheet material is implemented as an air bag material with a Composition Parameter, which can be applied to determine the appropriate lamination temperatures to a multiphase polymer formulation chosen to meet the requirements of an air bag application. given, as defined by the inflation temperature.

The rolling process is carried out in the conventional manner with the conventional apparatus. The film could be thermally laminated to the cloth substrate immediately upon processing or later. The heat is applied as required and according to the characteristics of the film and the fabric.

The additionally industrial utility of the present invention contains the attribute of the lamination, whereby a tightly bonded material could easily be delaminated, when required, for the recycling of the layer materials without substantial cross-contamination.

With respect to the method of making the composite sheet material, it can be cut and sewn using the techniques used for a conventionally coated fabric. In this regard, reference could be made to US Patent No. 5,529,340 published June 25, 1996 by Fairbanks, the exhibits of which are incorporated herein by reference. This patent discloses a single pattern piece, which is sewn, along the cutting edges of the pattern in a sequence designed to provide an air pocket when fully inflated. Any other known technique could be used to build an air bag using the material of the present invention.

It should be noted that the fabric to which the film is bonded could be woven, nonwoven, knit by spikes or spun and made of polyamide or polyester yarn or fiber.

The film can typically be made thin from 15-100 microns but preferably 15-40 microns.

DETAILED DESCRIPTION OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings that are used only to illustrate the invention, Figure 1 is a graphic representation of a diagram of the composition of the polymer system that relates to the present invention; Figure 2 is a graphical representation of the composition parameter f (c) of the formulations located in the diagram of the polymer composition of Figure 1; Y Figure 3 is a graphical representation of the relationship between the measured sealing temperature and the composition parameter, f (c).

In Figure 2 of the drawings, the following legend is applied.

A is the composition region of the preferred embodiment; B is the region of increased formality; and C is the region of the thermal properties increased.

A 'Composite Material' is defined in the Concise Encyclopedia of Science &Technology "(3rd, Ed., Sybil P. Parker (Ed.), McGraw-Hill Inc., 1994) as a 'material that results when two or more Materials, each having its own, usually different characteristics, combine to provide the compound with properties useful for specific applications. Each of the input materials should serve as a specific function in the compound, which should instead show improved or new distinctive features. " The present invention is about compounds created by the dispersion in thermoplastic polyamide copolymers of low melting ethylene copolymers, elastomeric having functionality that imparts improved resistance to environmental stresses, such as those due to heat and moisture and chemicals, while the properties valued in a thermoplastic material, such as strength and flexibility and formability, are preserved. It could be said of these compounds that the properties of the "barrier" of the thermoplastic materials thus formed have been improved, and the present invention is about compounds comprised of discrete layers, the layers contribute to their respective attributes for the development of the compound. strong, thin flexible films provide light weight, effective coverage of surfaces: as fabrics of anisotropic structures that absorb energy, providing 'resistance' to the forms that are subjected to biaxially directed efforts at high deformation speeds: viz., materials of the airbag .

DESCRIPTION OF POLYMERIC SYSTEMS The polymers comprising the polymeric film are the compounds of the present invention have been set forth in a U.S. Patent Application No. 60 / 014,150 published March 25, 1996 in the name of N. Farkas (the expositions of which are incorporated herein). here by reference). It should be emphasized that the present invention relates to a function that could be employed to combine the components of the resulting polymer in such a way that the properties of the resulting film are predictable and can be made adapted to the desired application. This represents a significant advance in art.

The method of the present invention involves melt blending by the conventional means of the polymers of the main categories described above, to create the formulations of the multistage thermoplastic polymer, wherein the compositions of the polymeric components in the formulations are determine according to the needs of the application.

Consider the creation of a polymeric binary phase system, mixed by melting two components selected from the main categories (PA-I) and (PA-II), which comprises: from 5 to about 50% by weight of at least one linear aliphatic polyamide resin having a narrow melting point range, a melting point greater than 200 ° C, and having a number average molecular weight of at least about 5000; ii) from about 50 to about 95% by weight of at least one polyamide resin comprising at least one pendant alkyl branch having 1 to 3 carbon atoms within at least two amide bonds along the structure of the polymer and at least one sequence of at least seven consecutive carbon atoms, excluding the carbon atoms in the pendant alkyl branches, if any, within at least two amide bonds along the polymer structure, the point of fusion of the polyamide that is lower than 200 ° C.

Specifically, for the purpose of illustration, consider the melt mixture of 30% by weight of pol i caproamide (as the PA-I component) with 70% by weight of the homopolymer of 2-met ilpent ame ti lendiamine and dodecandioic acid ( as the PA-II component). With the practical improvement of melt mixing and the art of film formation, a film could be melted which will expose the thermal characteristics between those of the two components comprising the mixture. The film could be heat fused to it, or to a fabric substrate, by conventional rolling means with relative ease, at a sealing temperature of about 160 ° C, as measured by the methods described below.

Now consider the creation of a tertiary multiphase polymeric system by melt blending of the combination mentioned above, whereby part of the PA-II component is replaced with an ingredient, or ingredients selected from the third major category (f-PO): i) from about 5 to about 40% by weight of at least one ethylene copolymer, E / X / Y, wherein E is ethylene and is at least 50% by weight of E / X / Y, X is 1- 35% by weight of an acid containing monocarboxylic acid, and Y is 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms, and wherein further the acid groups in the acid-containing radical are neutralized from 0-100% by weight of a metal ion; ii) from about 0.5 to about 10% by weight of at least one polymeric insertion agent containing the reactive groups selected from at least one of epoxides, isocyanates, aziridines, silanes, alkyl halides, alpha-halo ketones and aldehydes or oxazoline, which reacts with the radicals containing acid in component iii) and further reacts with the insertion sites of the components (PA-I) and (PA-II), and the weight percent of the monomer (s) contained therein The reactive groups is 0.5-15 weight percent of the polymeric insertion agent, and the remainder of the polymeric insertion agent contains at least 50% by weight of ethylene and 0-49% by weight of a radical derived from at least one acrylate. alkyl, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms; Y iii) from 0 to about 40% by weight of at least one C2-C20 polyolefin selected from polyethylene, polypropylene, ethylene propylene diene terpolymer, copolymers of ethylene with vinyl acetate, carbon monoxide or ethylenically unsaturated carboxylic acids or esters of the same on which are inserted from about 0.05 to about 5% by weight of monomers or mixtures of monomers selected from ethylenically unsaturated acid monomers or their derivatives including acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid , 5-norboren-2, 3-dicarboxylic acid, maleic anhydride, monomethyl fumarate and monomethyl maleate; and ethylenically unsaturated monomers containing the amino or hydroxy functional groups including vinyl pyridines, vinyl silanes, 4-vinyl pyridine, vinyltriethyloxysilane and allyl alcohol.

Specifically, for the purpose of illustration, consider the melt mixture of 30% by weight of polyproamide (as the PA-I component) with 30% by weight of the homopolymer of 2-methylpentamet-ilenediamine and dodecandioic acid (as the component PA- II), and with 40% by weight of a combination of an ionomer, such as the zinc neutralized salt of an ethylene copolymer selected from the sub-category (i) of the category (f-PO), and a compatibilizer such as a copolymer derived from ethylene / n-butyl acrylate / glycidyl methacrylate selected from subcategory (ii) of category (f-PO).

That is, 40% of the component (PA-II) has been substituted with the combination of the ingredients withdrawn from the category (f-PO), while the proportion of the (PA-I) in the formulation of the mixture is maintained. end constant at 30%. In each case, the formulations set forth herein could include antioxidants, thermal stabilizers or mixtures thereof. Typically these comprise from about 0.05 to about 2.0% by weight. Other optional ingredients could be selected from flame retardants, anti-blocking agents, slip additives, pigments or dyes, processing aids, plasticizers and ultraviolet blocking agents. These could be used in appropriate amounts as are well known to those skilled in the art.

A film could be melted from a molten mixture of the formulation mentioned above with relative ease. The film could be fused by heat to it, or to a cloth substrate, by the conventional lamination means with relative ease, at a sealing temperature of approximately 220 ° C, as measured by the methods described below.

This measured sealing temperature is 50 ° C higher than that exhibited by the binary mixture containing the same proportions of the higher melting polyamide, viz. 30% in the lower melting point polyamide. In this way the incorporation of the ingredients of the selected low melting point 'functionalized polyolefin', by means of conventional thermoplastic mixing means, leads to the creation of a multiphase polymer system, which when melted by means of the melting medium. of conventional thermoplastic film, it creates a film of material with the properties of: high thermal barrier, hard surface characteristics (so called 'anti-blocking' characteristics), ease of formability, strong self-adhesive ion, and strong adhesion to substrate materials such as fabrics.

Two cases of the combination of the represented components of the three categories (PA-I), (PA-II) and (f-PO), have been cited previously, to create a binary and tertiary system. These cases could be considered to belong to a continuum of polymeric systems, which can be represented in a conventional triangular composition diagram (Figure 1) in which the apices are as shown in Table 1.

The representation of the diagram of the tertiary composition of the continuum of the polymer systems is shown in Figure 1 as observed.

The technology of joining the low melting elastomeric ethylene copolymers to the high melting polyamide resins together, to obtain the synergistic combination of the properties of the two categories of materials is known to those skilled in the art. The application of the effect of imparting the properties associated with thermoforming films to thermoplastics, which are then used as layers in composite sheets such as airbag materials (for example), have not been previously known.

The functionality imparted to the polymer systems by the respective categories of the components could be represented schematically as shown in the following Table 2.

This formalism supports the purpose that the compositions of the polymer system could be represented by the simple function: = [PA- I] + [f - PO] [PA - II] + [f - PO] ([PA-I] + [PA-II] + [f-PO] = 1) where f (c) = Composition Parameter; [PA-I] = concentration of polyamide (PAl); [PA- I I] = concentration of polyamide (PA-II); and [f-PO] = concentration of (f-PO). The values of the composition parameter, f (c), associated with the tertiary mixture, and the three binary mixtures, at the nominal values of the compositions of these formulations comprising the mixtures, is shown in Table 3.

The shape of the function reflects the essential physics of multiphase polymer systems. The component (f-PO) of the tertiary system is comprised of the copolymer or copolymers based on low melting point ethylene. It contributes to dimensional stability and thermal and moisture resistance, through the stabilization of micro-morphology, and contributes to the macro-morphology desired for formability, anti-blocking. Hence the appearance of the term [f-PO] in the numerator of the parameter, with the 'high temperature polyamide ", and the appearance in the denominator of the parameter, with the low temperature polyamide.The parameter is indeed the compositional relationship from the high-temperature contibu- tors to the multiphase system functionality, to the low temperature contibu- tors.

The practical limitations apply to the region of the continuum over which the functional relationship, given in Equation (1) applies, as follows: a) a value of 1.0 does not have the significant physical meaning in [f-PO] = 1.0 (p. e j., in the pure apex (f-PO); b) also the value of 0 in [PA-II] = 1.0 has no meaning (eg, (PA-II) pure; c) there is a mathematical singularity in [PA-I] = 1 Given the importance of the component (f-PO) for the functionality of the system, it is unlikely that the values of the parameter throughout the compositions (f-PO) on which the functional parameter has the meaning that it is probably 0 < [f-PO] < approximately 0.5, on which the Composition Parameter takes the values within the range of: O < f (c) < 2.0 The values of the Composition Parameter, f (c) taken by the formulations, located at different points on the Composition Diagram of Figure 1, are illustrated in Figure 2.

The meaning of the function f (c) is that it correlates with the two parameters, which are the key to the selection of the airbag materials for use in the applications of the given airbags, formed by the binding Thermal film to the fabric: a) the characteristics of thermal resistance of the material; the ease with which the film can be laminated This is illustrated for the case of the three formulations set forth in Table 4 below.

Thus, new hybrid airbag structures for automotive passive limitation systems, which equal or exceed the usefulness of those produced from silicone-coated fabrics, are contemplated in the present invention. The means to formulate and design them offers the best 'balance' between the functionality in use (the requirements that are established are defined by the inflation regimes), and the ease of manufacture of the laminate (reflected in the width of the 'window' in the rolling process). All this constitutes an advance in the art of the airbag.

In the event that a material of the airbag is selected for an application in which inflation is to be carried by means of very hot inflation gases, then a film composed of a formulation with a high value of f would be selected ( c) On the other hand, where low temperature inflation is to be used, in this case the lower thermal resistance requirement can be taken advantage of to select a formulation with a wide lamination "window" of operation at relatively low seal temperatures, it would be advisable a low value of f (c).

Multiphase tertiary polymeric systems that have a value of a performance index depending on the composition of about 1.0, this is the formulations of films that would exhibit a good balance of thermal resistance and formability, are proposed for the materials of Airbags to be used with conventional azide-based inflation systems In the method of the present invention, there is contemplated a means for formulating the multiphase polymer systems for film conversion, preferably melting, into the film / fabric laminates, in a manner that the prescribed thermal characteristics are imparted for use in different inflation temperature regimes.

Inflation of an airbag is most commonly effected by ignition of the sodium azide blowing agent, so that the requirement of the material in contact with the gases offers thermal barrier protection against pyrotechnic damage, and penetration by associated hot particulates. with incomplete combustion of the impelling agent. Trends are established with respect to the inflation of the airbags by means of "cold" gas systems and gases warmer than the nitrogen of the azide system, but cleaner, they are not contaminated by particulates.

Elaboration Methods The polymerization of the components of the categories comprising the formulations, of which the film layer of the composite structure is made, follows the well-established practices that apply to polyamides and ethylene copolymers. If required, the aives for the formulations could be incorporated by conventional means either in the polymerization stages or the formation of the product, the choice of the aive aion point depends on the known art.

The various ingredients comprising a formulation could be melt blended under the cutting conditions, which have first been mixed as solid ingredients, for example, as pellets and / or powders or could be incorporated by means of simultaneous or separate measurement. It could be advantageous for the ingredients to be mixed in one or more steps in one or more sections of the mixing equipment such as an extruder, or the mixers exemplified by the Branbury, Buess kneader or the Ferrell continuous mixing equipment. As an example, for the purpose of promoting the insertion reactions between the polymeric insert component of sub-category (ii) of the category (f-PO), and one or both of the thermoplastic components (PA-I) ) and (PA-II), the components of these categories could be combined first before the aion of the acid-containing copolymer of the sub-cat egorí to (i) of the category (f-PO) that is added downstream. It should be noted that a non-extruded cross-linking product would result if the components of sub-categories (i) and (ii) of the category (f-PO) were added to a mixing device, such as an extruder, when a polyamide of the categories (PA-I) and / or (PA-II) was not present.

The ingredients are properly dispersed by resorting to high shear in the mixing, to ensure that the insertion reactions proceed uniformly throughout the mixture, and to achieve the desired morphology of the formed film. For example, it is known to those skilled in the art that the desired morphology is characterized by at least one of the continuous phases of the mixture, the thermoplastic component being of the category (PA-I), and optionally of (PA-II) .

The formation of the film could be by melting or by a process of blowing the film, both of which are known in the art of making thermoplastic films. The film could be mono or multilayer, the last being formed, for example, by lamination or coextrusion. These films could be mono or biaxially oriented. The properties of the films relate to factors such as the screw design of the extruder, the extrusion temperature and the dwell time, the speed and degree of shutdown, the thickness of the film and the nature and quantity of the films. additional ingredients present in the formulation as the main components or additives. The film used to make the laminates of the present invention is typically 1 mil thick.

Lamination of the film to the fabric can be done in a number of ways. One method is to pass the film and the fabric through a group of heated press rolls. Alternatively, by applying the art of extrusion coating, a molten polymer could be extruded onto the fabric and allowed to solidify in a continuous film. By applying the powder coating art, a powder, which is distributed on the fabric substrate in a controlled manner, could melt, and then the polymer layer thus formed allows to solidify.

The laminate could be cut and sewn using the techniques used for conventionally coated fabrics. US Patent 5 529 340, published by Fairbanks on June 25, 1996, discloses a single-pattern piece, which is sewn along the cut edges of the pattern in a sequence designated to provide an air pocket when worn. inflates completely.

Where the structure of the composite sheet is that of a real laminate, that is, wherein the material of the contact film layer, while forming a bond towards the upper fibers of the cloth substrate sufficiently strong to ensure that the requirements of the application are satisfied, the voids of the fabric substrate have not been penetrated to the extent of effectively integrating the materials of the film with those of the fabric, those skilled in the art contemplate the techniques for separating a film layer from a substrate of fabric by mechanical means, optionally thermal explosion, but without resorting to the use of solvents to weaken chemical bonds.

While the composite sheet material of the present invention is formed without resorting to an adhesive layer between the layers of the film and the fabric substrate, the layer or layers of the film could be delaminated from the fabric substrate by mechanical, aided means optionally by the application of heat. The purpose of the de-lamination is the separation of the film layer from the composite structure of the fabric substrate substantially without cross-contamination.

The deconstruction of the composite sheet could be carried out by a number of means. A process for separating the primary and secondary backup components from the folders is described in US Pat. No. 5,230,473, whereby the backing of a folder is removed using the rotating toothed rollers. An apparatus based on this method could be visualized, whereby the film is removed from the fabric. A composite sheet as a material of the air bag could be cut and distributed flat on a moving band, during the step on which the film could be subjected to a high speed rotating press roller. The anticipated effect is that the flakes of the film would form, which could be removed from the fabric substrate by suction. Alternatively, the composite sheet material could be shredded into pieces small enough for the fiber film, and then using the density separation technologies, the film fragments could be sorted from the fibers.

EXAMPLES The following examples illustrate various embodiments of the present invention and comprise the current forms of the same.

TEST METHODS The essential concept for bonding a layer of the thermoplastic film of a multiphase polymer system to a cloth substrate by chemical bonding was confirmed by carrying out a number of experiments, which are illustrated in the Examples. The assignments of the illustrative examples are listed in Table 5 below.

The polymer materials comprising the formulations of the present invention are exemplified, by, but not limited to, that listed in the following Table 6. These materials were used in the experimentation.

Table 7 lists the methods for manufacturing and testing the samples, which were used in the experimentation, are reported in the Examples. These manufacturing methods simulate on a small scale the processing methods that have been described as being suitable for making composite sheet materials for industrial application.

In the table, the numbers listed refer to the annotations that continue in Table 7.

Note 1: Extrusion conditions The blends were extruded in the 0.8-inch Welding Engineers non-inter-mesh twin-screw counter-rotating extruder, which has an L / D of about 40, which was operated at the appropriate melting temperatures for polycaproamide processing , PA- 6.

Note 2: Fade conditions The melt was extruded through a flat die 6 inches in diameter. The extrudate was quenched on a calibrated frozen roller at temperatures nominally within the range of 10 ° C to 15 ° C, to form the films of approximately 1 millionth of thickness.

Note 3: Properties of Fabric Substrates The fabric substrates that could serve as substrate materials for the composite sheets formed by the method of the present invention are exemplified by, but not limited to, those listed in the following Table 8. Two cloth, plain woven filament substrates of 420 denier and 630 denier of pol ihexameti lendipamide (PA-66), were used in the experimentation.

Note 4: Lamination In the lamination test, the seal of the film to the fabric was made using a Sencorp thermal sealer, the arrangement of which is schematically shown below: Qui j ada Film Response Pei i cula Qui j ada lower teflon Quick teflon TC for para for sealer protect protect sealant Sencorp el Sencorp heated element heated element A fast response thermocouple and a HIOKI 8811 fast recorder were used to measure the temperatures that occur during the lamination of the film to the fabric, and the dynamics of the heat transfer, to determine the resting times in the seal.

The seal method is summarized as follows: a) the upper and lower jaws of the sealant were heated continuously, the jaws were preheated by the closing cycles of the jaws; the resting time was set at 0.5 seconds and a maximum jaw pressure of 62.5 psig.

Note 5: Measurement of sealing temperature The jaw set point is used to provide the results of the 'Measured Seal Temperature' consistently throughout the entire experiment.

The surface temperature of the jaws in the Sencorp thermal sealant was measured and compared to the set point: the surface temperature equaled the set point within ± 1 ° C. A substantial drop in the temperature that existed through the Teflon films on the face of the jaw was observed. The calibration experiments, a difference of the order of 40 ° C was observed between the temperature point of the jaw temperature and the temperature of the laminate between the Teflon films on the faces of the jaws.

Note 6: The Quantitative Adhesion Strength Result was obtained The average force required to separate by detachment of the film and the fabric was measured on an Instron, which has a crosshead speed of 12 inches / min, and which has an initial jaw spacing of 1 inch Note 7: Estimation of the "Operation Window" of the Seal The manual detachment of the laminates according to the seal temperature was increased, it was used to locate the beginning of the formation of a good bond, and therefore the lower limit of the "Operation Window" of the seal. Penetration of the material comprising the film layer on the cloth substrate was used to determine the upper limit of the range of the sealing temperature.

Example 1 The factor varied in the illustrated experiment is the formulation of the film layer. The bonding forces associated with three formulations referred to with the present invention are compared to the bonding forces associated with two reference polyamide systems: one of which is used extensively in adhesive formulations (generally solvent-based) of the type used in the adhesive formulations for the sewing connection of the yarns for athletes' shoes; and, one that is not used as an adhesive Table 9 summarizes the experimental conditions. The methods used in the manufacture of the film / cloth laminates in the Sencorp Sealer, and in carrying out the measurement of the adhesion force, have been described in detail above.

The results of the experiment are summarized in Table 10 below. The formulations related to the invention exhibit good bond strengths in relation to the recognized adhesive copolyamide, and to the polyamide not shown for its adhesive properties.

Example 2 The laminate samples of the two film formulations related to the present invention, on the 630 denier thread fabric, were immersed in liquid nitrogen, then cut with a pair of scissors. The image was formed on the cut surface using the Scanning Electron Microscopy (SEM). The SEM images were confirmed by light microscopy examination of the samples, which were mounted on epoxy resin, cured and polished. The observations are summarized in Table 11.

At lamination operation temperatures, below the range of the sealing temperature, little or no binding was observed. Within the range of the sealing temperature, one is formed, which resists the efforts to detach the film from the fabric. At temperatures above the sealing temperature range, it was observed to flow into the interstices of the fabric, producing a "monolayer" fabric.The observations are summarized in Table 12.

Example 3 A series of 1 millionth films were fused from the formulations created by the melted mixed components of the categories (PA-I) and (PA-II) in different proportions, and a series of 1 millionth films were fused from the formulations created by the melted mixed components of the categories (PA-I), (PA-II) and (f-PO) in different proportions. The specific components representative of these categories, which were used in the illustrated experiment, are listed in Table 13.

The results of the experimental series are summarized in Table 14.

The binary mixtures in the proportions [PA-I]: [PA-II]: 30:70, 40:60 and 50:50 could not be made. The "Bands" at the exit of the extruder showed poor mixing.When the ingredients of the category (f-PO) were added to the throat of the extruder, the quality of the film improved and all the proportions of the mixture melted. ingredients based on the ethylene copolymer act as compatibilizer of the nylon film, as indicated by the results in the Table above, the presence of this component of the tertiary polymer system also serves to increase the sealing temperature of the formulation.

The sealing temperature of a binary mixture, in which the component (PA-I) is present in 20%, has a value of 175 ° C. The sealing temperature of a tertiary mixture, in which the component (PA-I) is present in 18%, while by means of the substitution of (40/82)% of the component (PA-II), the component ( f-PO) is present in 40%, has a value of 210 ° C, as shown in Table 15.

As discussed previously, there is a substantial difference between the temperature of the jaw, referred to as the Seal Temperature Measured in the results of the Illustrative Examples, and the temperature reached by the material of the cloth / cloth during sealing. . Because the temperature of the jaw was used throughout the experimentation, the result that pertains to the sealing temperature of the formulations is internally inconsistent.

Example 4 A series of 1 millionth films were fused from the formulations created by the components of the melted mixture of the categories (PA-I), (PA-II) and (f-PO) in different proportions. The specific components representative of these categories, which were used in the illustrated experiment, are listed in Table 16.

The compositions of the polymer system were represented by the simple function, referred to as the Composition Parameter: [PA-!] + [/ - PO] f (c) = [PA-II] + [f-PO] [PA-I] + [PA-II] + [f-PO] = 1 where f (c! Composition Parameter [PA-I] = concentration of polyamide (PAl) [PA- I I] = concentration of polyamide (PA- I I) [f-PO] = concentration of (f-PO) The computed values of the Composition Parameter associated with the formulations created, and the respective measured sealing temperatures of the formulations, are shown in Table 17.

For the purpose of comparison, the Computed Composition Parameter and the measured sealing temperatures of the two binary mixtures of the ingredients of the category (f-PO) first with the polyamide (PA-I), and then the polyamide (PA -II), are given in Table 18.

Example 5 The factor varied in the illustrative example is the nominal Melting Point of the comparison of the polymer system of the laminated film to the cloth substrate. A thermal characteristic such as the nominal melting point would be of primary importance in the selection of a formulation for a given application.

The results of Table 19 show that the formulations related to the present invention formed good films, and a good sealing quality was achieved, at the Sealing Temperatures Measures that varied in a linear manner, predictable with the nominal melting temperature of the polymer. The two polyamide homopolymers, referred to in Table 19 as PA-6 and PA-6,12, did not form good quality seals.

Example 6 A series of one millionth films were fused from the formulations created by the components of the molten mixture of the three categories (PA-I), (PA-II) and (f-PO) in different proportions. The lamination of the films to the 420 denier cloth substrate was carried out in the Sencorp sealer at a series of temperatures.

The manual detachment of the laminates, formed as the sealing temperature was increased, was used to locate the start of the formation of a good joint and therefore the lower limit of the sealing 'Operation window'. The penetration of the material comprising the film layer on the cloth substrate was used to determine the upper limit of the seal temperature range.

The results are indicated in Table 20. At a temperature at which the bond strength was observed to be poor, a 'P' is assigned.Where a good bond strength was evident, it was apparent that a structure had formed. of real laminate, and an 'L' is assigned. The appearance of good bond formation, while the current bond strength was apparently not adequate, was indicated by the assignment of 'P to L', which means the transition from the poor adhesion strength to the state where a real laminate is formed, similarly, where the adequate bond strength was evident, but there was indicating that some of the material of the film layer had melted and penetrated the holes in the fabric, an 'L to M' is assigned. Where it was apparent that the material of the film layer had been melted by the sealing conditions, resulting in the formation of an integral film and the structure of the cloth substrate, essentially a monolayer structure, an 'M' is assigned. .

Moving down the rows of Table 20, the location of the rolling 'Operation Window', as defined by the temperature range at which a real laminate is formed, is observed to follow the direction of the lower temperatures at higher temperatures ^ The Composition Parameter values, f (c), associated with the formulations that move in the lower direction of the rows of the table, increase from a value of zero associated with the formulation of row 1 , up to a value of 1.0 associated with the formulation of row 5.

Example 7 A series of one millionth films were fused from the formulations created by the components of the molten mixture of the three categories (PA-I), (PA-II) and (f-PO) in different proportions.

Three groups of experiments were carried out: a) on the virgin film, to serve as a 'Control', b) on the film exposed to pressures and temperatures associated with the rolling conditions: and c) on the film subjected to the conditions associated with the thermal aging characteristics tested.

In part a) the samples were cut from the roller, conditioned in the PT laboratory for 40 hours, then subjected to stress strain testing in the Instron.

The second experiment was designed to simulate the sealing process. A piece of the film was interposed between Teflon tapes (giving jaw / Teflon / Teflon / film / Teflon / Teflon / jaw), inserted into the Sencorp sealant and 'laminated' to the conditions of 0.5 seconds and the pressure maximum (line pressure of 62.5 psig) A sample of the 4"x 1/2" film was created to be tested on the Instron.The use of the two Teflon strips was intended to equalize the thermal resistance provided by the fabric, and to ensure that the film does not stick to the jaws of the Sencorp sealer.

The third experiment was intended to simulate the effect on the physical properties of the film only from the application of heat. The film was inserted in a hot air oven and then removed after a short time. The furnace temperature was adjusted to equal the interfacial temperature measured in the lamination. A thermocouple of low thermal inertia was attached to the surface of the film to monitor its temperature. Once the thermocouple reached the interfacial temperature, the film was removed from the oven.

It is apparent from the results set forth in Table 21 that the effect on the physical properties of the film material, which has been subjected to conditions simulating those experienced by the film in the lamination, is comparable with the effect of the physical properties of the film material, which has been subjected to the conditions associated with the thermal aging test. Because the rolling conditions employed in small-scale experimentation are severe, the process for forming a film and the fabric composite structure by thermal lamination would not be expected to have a counterproductive effect on the strength of the film component of the film. the structure The present invention provides a means for making a composite sheet material by thermal bonding without adhesives, in a manner that balances the requirements imposed by the different inflation temperature regimes, and the need to separate the layers of the composite for the purpose of the pre and post consumer recovery of the materials of the layers without cross contamination.

Those skilled in the art will recognize that many modifications and variations of the present invention are possible in the clarity of the foregoing teachings. It is therefore understood that within the scope of the appended claims, the invention could be practiced other than as specifically described.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, the content of the following is claimed as property.

Claims (24)

RE I lND ICATIONE S

1. A composite sheet material of the air bag, characterized in that it comprises a polymeric polyamide film adhered to a fabric, the polymeric polyamide film is selected from the films having a melting point of less than about 220 ° C and having the minus some adjacent amide bonds along its polymeric structure, at least one C-C3 pendant alkyl branch, at least one sequence of at least seven consecutive carbon atoms, and the fabric is selected from polyamides and polymers.

2. The composite sheet material of the air bag as claimed in claim 1, characterized in that the one of the polymeric polyamide film has at least some adjacent amide bonds along its polymer structure, at least one alkyl branching. C! -C3 pendant, at least one sequence of at least seven consecutive carbon atoms and a melting point in the range of about 100 ° C to about 200 ° C.

The composite sheet material of the air bag as claimed in claim 2, characterized in that the polyamide polymer film comprises a monolayer film of a mixture of polyamides, a multilayer film of polyamides or a co-extruded film of polyamides.

4. The composite sheet material of the air bag as claimed in claim 1, characterized in that the polyamide polymer film is selected from polyamide films having a melting point of less than 200 ° C and a lower degree of crystallinity than the nylon 66.

5. The composite sheet material of the air bag as claimed in claim 1, characterized in that the polyamide is prepared from (a) at least one dicarboxylic acid and at least one diamine, wherein at least one dicarboxylic acid and / or at least one diamine contain at least one pendant alkyl branch having from one to three carbon atoms, and wherein at minus one dicarboxylic acid and / or at least one diamine have a sequence of at least seven methylene groups; (b) at least one alpha, omega aminocarboxylic acid, having the formula of H2N-R1-C00H, wherein R1 is an aliphatic radical having at least seven methylene group in the sequence and a pendant alkyl branching having one to three carbon atoms; (c) at least one diamine and at least one nitrile selected from the group consisting of alpha nitriles, omega-amino alkylene and alpha omega alkylene dinitriles, wherein the diamine, nitrile and / or dinitrile contain at least one branching pendant alkyl having from one to three carbon atoms; and wherein the diamine, nitrile and / or dinitrile comprise at least seven methylene groups; or (d) mixtures of any of the monomers described in (a) - (c) above.

6. The composite sheet material of the air bag as claimed in claim 5, characterized in that the other monomers used to prepare the polyamide of the present invention are selected from the aromatic dicarboxylic acids, aromatic diamines, alicyclic dicarboxylic acids and alicyclic diamines.

7. The composite sheet material of the air bag as claimed in claim 5, characterized in that the aromatic dicarboxylic acids are selected from terephthalic acid and isophthalic acid, the alicyclic dicarboxylic acid is 1,4-bismethylene cyclohexyl dicarboxylic acid and the diamine is 1,4-bismethyl diamino cyclohexane.

8. The composite sheet material of the air bag as claimed in claim 5, characterized in that the polymer film is based on the copolymers and terpolymers of hexamethylene diamine, 2-me ti lpent amethylendamine, adipic acid, dodecandioic acid and epsilon-caprolactam (nylon 6).

9. The composite sheet material of the air bag as claimed in claim 1 which consists of a fabric substrate laminated to a polymeric film layer, wherein the film layer is formed of a multiphase polymer system, characterized in that it comprises : at least one linear aliphatic polyamide resin (PA-I), which has a temperature range of narrow melting point, a melting point in excess of 200 ° C and a molecular weight of at least 5000; at least one polyamide resin (PA-II) comprising at least one pendant alkyl branch having from 1 to 3 carbon atoms within at least two amide bonds along the polymer structure and at least one sequence of at least seven consecutive carbon atoms, excluding the carbon atoms in the pendant alkyl branches, if any, within at least two amide bonds along the polymer structure, the melting point of the polyamide which is less than 200 ° C; Y at least one component of (f-PO) comprising at least one of (i) an ethylene copolymer, E / X / Y, wherein E is ethylene and is at least 50% by weight of E / X / Y, X is 1-35% by weight of an acid containing acid unsaturated monocarboxylic acid, and Y is 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof, wherein the groups alkyl contains 1-12 carbon atoms, and wherein in addition the acid groups in the acid-containing radical are neutralized from 0-100% by weight of a metal ion; (ii) a polymeric insertion agent containing the reactive groups selected from at least one of epoxides, isocyanates, aziridines, silanes, alkyl halides, alpha-halo ketones and aldehydes or oxazoline, which reacts with the acid-containing radicals in the component i) and react additionally reacts with the insertion sites of the components (PA-I) and (PA-II), and the weight percent of the monomer (s) containing the reactive groups is 0.5-15 weight percent of the polymeric insertion agent, and the remainder of the polymeric insertion agent contains at least 50% by weight of ethylene and 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms; Y (iii) at least one C2-C20 polyolefin selected from polyethylene, polypropylene, ethylene propylene diene terpolymer, copolymers of ethylene with vinyl acetate, carbon monoxide or ethylenically unsaturated carboxylic acids or esters thereof onto which are inserted from about 0.05 to about 5% by weight of the monomers or mixtures of monomers selected from ethylenically unsaturated acid monomers or their derivatives including acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, 5-norboren-2 acid, 3-dicarboxylic, maleic anhydride, monomethyl fumarate and monomethyl maleate; and of ethylenically unsaturated monomers containing the amino or hydroxy functional groups including vinyl pyridines, vinyl silanes, 4-vinyl pyridine, vinyltriethyloxysilane and allyl alcohol; wherein the composition of the polymer system comprising the film layer is characterized by the function: f (c) =. { [PA-I] + [f-PO]} /. { [PA-II] + [f-PO]} ([PA-I] + [PA-II] + [f-PO] = 1) where f (c) = Composition Parameter; [PA- I] = concentration of polyamide (PA-I); [PA- 11] = concentration of polyamide (PA- I I); and [f-PO] = concentration of (f-PO), and f (c) has values in the range of about 0.5 to about 2.0; and the numerator mainly determines the properties of the thermal barrier of the film and the denominator mainly determines the temperature for laminating the film layer to the fabric substrate.

10. The composite sheet material as claimed in claim 9, characterized in that approximately equal amounts of PA-I, PA-II and f-PO are combined to form the film.

11. The composite sheet material of the air bag as claimed in claim 9, characterized in that the fabric is made of polyamide or polyester filaments or yarns and could be woven or non-woven or knitted.

12. The composite sheet material of the air bag as claimed in claim 9, characterized in that the film is a monolayer or multilayer film which is melted or blown or oriented and laminated or extruded.

13. The composite sheet material of the air bag as claimed in claim 9, characterized in that it comprises multiple layers of film and fabric that include the layers of the laminated film to the layers of the film.

14. A rolling process for making a composite sheet material of the air bag as claimed in claim 9, characterized in that the rolling temperature is determined according to the function f (c) as defined herein, and wherein the The properties of the film do not deteriorate and a real laminate is obtained.

15. A method for making an air bag for use in a passive restraint system, characterized in that it comprises constructing an air bag of a composite sheet material as claimed in claim 9, cutting and sewing the composite sheet material in accordance with a configuration of the desired airbag.

16. A method for recovering the components of the composite sheet material from the air bag as claimed in claim 9, characterized in that the material could be delaminated mechanically using the thermal means, if necessary and substantially without cross-contamination of the components.

17. A method for recovering the components of the composite sheet material of the air bag as claimed in claim 9, characterized in that it comprises disassembling the material from its inflation module, when required; deconstructing the structure of the air bag, as needed, subjecting the material to a mechanical demolding process, optionally including the thermal lamination means; and recovering the components of the film and the fabric substantially without cross-contamination thereof for recycling.

18. An air bag constructed of a composite sheet material of the air bag as claimed in claim 9.

19. A passive restraint system, characterized in that it comprises an air bag as claimed in claim 18.

20. A method for selecting the formulation of a polymer system for a film that is used in a composite sheet material, characterized in that the composition of the polymer system is as claimed in claim 9 and is selected to impart functionality to the resulting film according to the function f (c) and where f (c) has the selected values to produce a composite sheet material which is a real laminate with sufficient strength to satisfy the requirements of the composite sheet.

21. A composite sheet material of the air bag as claimed in claim 9 which consists of a fabric substrate laminated to a polymeric film layer, wherein the film layer is formed of a multiphase polymer system, characterized in that it comprises from at least about 10% by weight to about 90% by weight of at least one linear aliphatic polyamide resin (PA-I), which has a temperature range of narrow melting point, a melting point in excess of 200 degrees C, and a molecular weight of at least 5000; Y from at least about 10% by weight to about 90% by weight of at least one polyamide resin (PA-II) comprising at least one pendant alkyl branch having from 1 to 3 carbon atoms within at least two bonds of amide along the polymer structure and at least one sequence of at least seven consecutive carbon atoms, excluding the carbon atoms in the pendant alkyl branches, if any, within at least two amide bonds throughout of the polymer structure, the melting point of polyamide that is less than 200 ° C.

22. The composite sheet material of the air bag as claimed in claim 9 which consists of a fabric substrate laminated to a polymeric film layer, wherein the film layer is formed of a multiphase polymer system, characterized in that it comprises : from at least about 10% by weight to about 90% by weight of at least one linear aliphatic polyamide (PA-I) resin, having a narrow melting temperature range, a melting point in excess of 200 C grades, and a molecular weight of at least 5000; Y from about 10% by weight to about 90% by weight of at least one (f-PO) component comprising at least one of (i) an ethylene copolymer, E / X / Y, wherein E is ethylene and is at least 50% by weight of E / X / Y, X is from about 1 to about 35% by weight of an acid containing the unsaturated monocarboxylic acid, and Y is 0 to about 49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures of the same, wherein the alkyl groups contain 1-12 carbon atoms, and wherein in addition the acid groups in the acid-containing radical are neutralized from 0-100% by weight of a metal ion; a polymeric insertion agent containing the reactive groups selected from at least one of epoxides, isocyanates, aziridines, silanes, alkyl halides, alpha-halo ketones and aldehydes or oxazoline, which reacts with the acid-containing radicals in component i) and reacts additionally reacts with the insertion sites of the components (PA-I) and (PA-II), and the weight percent of the monomer (s) containing the reactive groups is 0.5-15 weight percent of the insertion agent polymer, and the remainder of the polymeric insertion agent contains at least 50% by weight of ethylene and 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide , sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms; Y (iii) at least one C2-C20 polyolefin selected from polyethylene, polypropylene, ethylene propylene diene terpolymer, copolymers of ethylene with vinyl acetate, carbon monoxide or ethylenically unsaturated carboxylic acids or esters thereof onto which are inserted from about 0.05 to about 5% by weight of the monomers or mixtures of monomers selected from ethylenically unsaturated acid monomers or their derivatives including acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, 5-norboren-2 acid, 3-dicarboxylic, maleic anhydride, monomethyl fumarate and monomethyl maleate; and ethylenically unsaturated monomers containing the amino or hydroxy functional groups including vinyl pyridines, vinyl silanes, 4-vinyl pyridine, vinyl triet-yloxysilane and allyl alcohol.

23. The composite sheet material of the air bag as claimed in claim 9 which consists of a fabric substrate laminated to a polymeric film layer, wherein the film layer is formed of a multiphase polymer system, characterized in that it comprises : at least one polyamide resin (PA-II) comprising at least one pendant alkyl branch having from 1 to 3 carbon atoms within at least two amide bonds along the polymer structure and at least one sequence of at least seven consecutive carbon atoms, excluding the carbon atoms in the pendant alkyl branches, if any, within at least two amide bonds along the polymer structure, the melting point of the polyamide which is less than 200 ° C; Y at least one component of (f-PO) comprising at least one of: (i) an ethylene copolymer, E / X / Y, wherein E is ethylene and is at least 50% by weight of E / X / Y, X is 1-35% by weight of an acid containing acid unsaturated monocarboxylic acid, and Y is 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide, or mixtures thereof, wherein the groups alkyl contains 1-12 carbon atoms, and wherein in addition the acid groups in the acid-containing radical are neutralized from 0-100% by weight of a metal ion; (ii) a polymeric insertion agent containing the reactive groups selected from at least one of epoxides, isocyanates, aziridines, silanes, alkyl halides, alpha-halo ketones and aldehydes or oxazoline, which reacts with the acid-containing radicals in the component i) and react additionally reacts with the insertion sites of the components (PA-I) and (PA-II), and the weight percent of the monomer (s) containing the reactive groups is 0.5-15 weight percent of the polymeric insertion agent, and the remainder of the polymeric insertion agent contains at least 50% by weight of ethylene and 0-49% by weight of a radical derived from at least one alkyl acrylate, alkyl methacrylate, alkyl vinyl ether, carbon monoxide, sulfur dioxide or mixtures thereof wherein the alkyl groups contain 1-12 carbon atoms; Y (iii) at least one C2-C20 polyolefin selected from polyethylene, polypropylene, ethylene propylene diene terpolymer, copolymers of ethylene with vinyl acetate, carbon monoxide or ethylenically unsaturated carboxylic acids or esters thereof on which are inserted from about 0.05 to about 5% by weight of the monomers or mixtures of monomers selected from ethylenically unsaturated acid monomers or their derivatives including acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, 5-norboren-2 acid, 3-dicarboxylic, maleic anhydride, monomethyl fumarate and monomethyl maleate; and ethylenically unsaturated monomers containing the amino or hydroxy functional groups including vinyl pyridines, vinyl silanes, 4-vinyl pyridine, vinyl trie ti loxysilane and allyl alcohol;

24. The composite sheet material of the air bag as claimed in claim 21, 22 or 23, characterized in that the material is used to construct an air pocket for use in a passive restriction system.