Tire with non-spliced multilayered film innerliner

Abstract

The present invention relates to a pneumatic tire having a non-spliced film innerliner comprised of a plurality of film layers where said film layers are of varied film moduli physical properties.

Claims

1. A pneumatic tire is provided having a continuous, non-spliced, innerliner comprised of a multilayered innerliner film laminate circumferentially covering at least a portion of the tire carcass's inner surface; wherein the innermost film layer of said multilayered innerliner film laminate contains an RFL adhesive coating on its surface facing to the tire carcass to thereby provide said RFL coating between said innerliner film laminate and tire carcass, wherein said multilayered innerliner film laminate is comprised of at least 2 film layers; wherein the modulus of the multilayered innerliner film laminate is in a range of from about 8 to about 20 MPa; wherein said innerliner laminate is comprised of a laminate of plurality of film layers, where the innermost film layer has a film modulus less than the film modulus of the film laminate, and wherein: (A) said film layers have directionally increasing film moduli of at least about 0.5 MPa for each adjoining film of said laminate extending from the innermost film layer through the outermost film layer of said film laminate, or (B) said film layers have alternating film moduli of at least about 0.5 MPa for each adjoining film of said film laminate, or (C) said film layers have randomly distributed film moduli of at least about 0.5 MPa for each adjoining film of said film laminate, or (D) said film layers comprised of a combination of said directional increasing, alternating or randomly distributed film moduli of said film moduli, or (E) said film layers having any of said directionally increasing, alternating, randomly distributed or combination of film moduli of said film laminate of at least about 0.5 MPa for each adjoining film of said film laminate, provided however that at least 2 of said adjoining films of said film laminate have a film modulus differing by less than about 0.3 MPa, wherein the layers of said innerliner film laminate are comprised of: (1) from about 40 to about 85 weight percent of a thermoplastic polyamide-based polymer comprised of a copolymer of a diamine and dicarboxylic acid, and (2) a range of from about 15 to about 60 weight percent of a dispersion contained in said thermoplastic polyamide-based polymer comprised of at least one of: (a) copolymer or mixture comprised of a polyamide-based segment and a polyether-based segment, and (b) polymer comprised of at least one of polyalkylene glycol (e.g. at least one of polyethyleneglycol, polypropyleneglycol and polytetramethylene glycol), polyoxyalkylene diamine (e.g. at least one of polyoxyethylene diamine, polyoxypropylene diamine and polyoxytetramethylene diamine) and copolymers thereof.

2. The tire of claim 1 wherein the said dispersion contained in the thermoplastic polymer is in a form of domains thereof dispersed in said thermoplastic polyamide-based polymer.

3. The tire of claim 1 wherein the innermost film layer of said innerliner film laminate facing the tire rubber tire carcass through the RFL coating on said film has a film modulus in a range of from about 5 to about 11 MPa.

4. The tire of claim 1 wherein the innermost film layer of said innerliner film laminate has a film modulus of at least about 1 MPa less than the modulus of the innerliner film laminate.

5. The tire of claim 3 wherein the innermost film layer of said innerliner film laminate has a film modulus of at least about 1 MPa less than the modulus of the innerliner film laminate.

6. The tire of claim 1 wherein the film layers said film laminate have an individual thickness of at least about 2 microns.

7. The tire of claim 1 wherein the thickness of said RFL coating is less than 2microns.

8. The tire of claim 1 wherein tire rubber carcass is comprised of a sulfur curable diene-based elastomer comprised of at least one polymer of at least one of isoprene and of 1,3-butadiene and of styrene with at least one of isoprene and 1,3-butadiene, exclusive of a copolymer of isobutylene and diene hydrocarbon.

9. The tire of claim 1 wherein the thermoplastic diamine-based polymer of the innerliner film is a copolymer of diamine and dicarboxylic acid comprised of at least one of nylon 6, nylon 6-6, nylon 4,6,nylon 11, nylon 12, nylon 6,10 and nylon 6,12.

10. The tire of claim 1 wherein the thermoplastic diamine-based polymer of the innerliner film is comprised of at least one of polycaprolactam (nylon 6) and copolymer of hexamethylenediamine and adipic acid (nylon 6-6) where said thermoplastic polymer of said innerliner film contains a dispersion of a copolymer comprised of a polyamide segment and a polyether-based segment.

11. The tire of claim 1 wherein said RFL adhesive is comprised of a resorcinol-formaldehyde resin/styrene-butadiene-vinylpyridine latex optionally containing a styrene-butadiene rubber latex, and optionally containing a blocked isocyanate.

Description

SUMMARY AND PRACTICE OF THE INVENTION

(1) In accordance with this invention, a pneumatic tire is provided having a continuous, non-spliced, innerliner comprised of a multilayered innerliner film laminate circumferentially covering at least a portion of the tire carcass's inner surface (said innerliner laminate therefor extends around the entire circumference of the tire's inner surface facing the tire's inner air chamber);

(2) wherein innermost film layer of said multilayered innerliner film laminate contains an RFL adhesive coating on its innermost surface facing the tire carcass desirably having a thickness of less than 2 microns (the thin RFL coating is therefore positioned between the innerliner film laminate and tire carcass rubber surface);

(3) wherein said multilayered innerliner film laminate is comprised of at least 2, alternately at least 4, film layers, and alternately comprised of a range of from 2 to about 30, alternately a range of form 2 to about 15, film layers;

(4) wherein the multilayered innerliner film laminate has a film modulus in a range of from about 8 to about 20, alternately from about 12 to about 18, MPa;

(5) wherein said innerliner is a laminate comprised of said plurality of film layers where the innermost film layer (the film layer facing the tire rubber carcass with the said RFL adhesive therebetween) has a film modulus lower than the film modulus of the film laminate, for example, and for one embodiment, in a range of from about 5 to about 11 MPa and, for example and for one embodiment, at least about 1 MPa lower than the film modulus of the film laminate), and wherein:

(6) (A) said film layers have directionally increasing film moduli of at least about 0.5 MPa for each adjoining film of said laminate extending (axially extending, namely extending in a axial direction) from the innermost film layer through the outermost film layer of said film laminate, or

(7) (B) said film layers have alternating film moduli of at least about 0.5 MPa for each adjoining film of said film laminate, or

(8) (C) said film layers have randomly distributed film moduli of at least about 0.5 MPa for each adjoining film of said film laminate, or

(9) (D) said film layers comprised of a combination of said directional increasing, alternating or randomly distributed film moduli of said film moduli, or

(10) (E) said film layers having any of said directionally increasing, alternating, randomly distributed or combination of film moduli of said film laminate wherein at least 2, alternately from 2 to 4, of said adjoining films of said film laminate have a film modulus differing by less than about 0.3 MPa, alternately less than about 0.2 MPa,

(11) wherein the layers of said innerliner film are comprised of: (1) from about 40 to about 85 weight percent of a thermoplastic polyamide-based polymer (resin), which may be comprised of, for example, a copolymer of a diamine and dicarboxylic acid, and (2) a range of from about 15 to about 60 weight percent of a dispersion contained in said thermoplastic polyamide-based polymer comprised of at least one of: (a) copolymer or mixture comprised of a polyamide-based segment and a polyether-based segment, and (b) polymer comprised of at least one of polyalkylene glycol (e.g. at least one of polyethyleneglycol, polypropyleneglycol and polytetramethylene glycol), polyoxyalkylene diamine (e.g. at least one of polyoxyethylene diamine, polyoxypropylene diamine and polyoxytetramethylene diamine) and copolymers thereof.

(12) In one embodiment, the innermost film of said laminate has a film modulus lower than the film modulus of the laminate (to promote adaptability of the laminate to the tire rubber carcass, particularly to promote physical compatibility of the innerliner film with the surface of the tire rubber carcass through the thin RFL adhesive coating).

(13) In one embodiment, the outer surface of the innermost film layer (the surface facing the tire carcass) of said multilayer film laminate contains a thin RFL adhesive coating having a thickness of less than 2 microns. A purpose of the RFL coating on the surface of the innermost film layer is to promote adhesion (e.g. building tack) of the film laminate to the uncured tire carcass rubber and also to promote adhesion of the film laminate to the cured tire carcass rubber upon curing of the rubber tire carcass. The average thickness of the RFL coating of less than 2 microns is to rely upon the innerliner laminate to promote air permeability resistance with minimal interference of the RFL coating.

(14) In one embodiment, the said dispersion is in a form of domains thereof dispersed in said thermoplastic polymer.

(15) In practice, an increase in concentration of said dispersion in said film layer is provided sufficient to provide an appropriate increase, or decrease, in its film modulus. For example, said dispersion (content or concentration of the dispersion) in a film layer may be decreased to promote an increase in its film modulus as well as an envisioned increase in its air permeability resistance.

(16) In practice, as indicated, it is desired that the innermost layer of said innerliner film laminate facing the tire rubber tire carcass, through the RFL coating on said film, has a lower film modulus than the laminate such as, for example, a film modulus in a range of form about 5 to about 11 MPa so long as it is lower than the film modulus of the laminate. (For example, its film modulus is desirably at least one MPa lower than the film modulus of the film laminate excluding, of course, the aforesaid RFL coating on the innermost surface of the film laminate.)

(17) In practice, the innermost surface of the innerliner film containing the RFL adhesive coating to provide building tack between the innerliner film and uncured tire rubber carcass and to be thereby cohesively adhered, or bonded, by the RFL adhesive to the tire rubber carcass. Such tire rubber carcass is generally comprised of a sulfur curable diene-based elastomer comprised of at least one polymer of at least one of isoprene and of 1,3-butadiene and of styrene with at least one of isoprene and 1,3-butadiene, wherein said elastomer is desirably exclusive of a copolymer of isobutylene and diene hydrocarbon.

(18) As indicated, the layers of the multilayered innerliner film laminate are comprised of a copolymer of diamine and dicarboxylic acid representative of which are at least one of nylon 6, nylon 6-6, nylon 4,6, nylon 11, nylon 12, nylon 6,10 and nylon 6,12, wherein at least one of nylon 6 and nylon 6-6 may be most desirable.

(19) A representative of tire innerliner films, in general and not intended to be limitative, may be found, for example, in U.S. Pat. No. 8,544,517 and U.S. Patent Publication Nos. 2013/0101821, 2013/0199686 and 2014/0227499 which are referenced and included herein in their entirety.

(20) Nylon is a generic designation for a family of synthetic thermoplastic polymers generally known as aliphatic polyamides as copolymers of a diamine and dicarboxylic acid. They are, generally, polymers composed of repeating units linked by amide bonds which are frequently referred to as being polyamides. Nylons are condensation polymers formed by reacting relatively equal parts of a diamine with a dicarboxylic acid. Amides are usually formed at both ends of each monomer. Chemical elements of the nylons include carbon, hydrogen, nitrogen and oxygen. For example, nylon 6 is reported as being a polycaprolactam having a melting point of about 220 C. Nylon 6-6 is reported as being a polymer of hexamethylenediamine (a 6 carbon diamine) and adipic acid (e.g. polyhexamethylene adipamide) having a melting point of about 265 C. Nylon 6,12 is reported as being a copolymer of a 6 carbon diamine and 12 carbon dicarboxylic acid.

(21) In one embodiment, and as previously indicated, only one side of the innermost film layer of the multilayered innerliner film laminate contains an RFL adhesive coating to promote bonding of the innerliner film to the adjoining carcass ply. Such RFL coating is typically comprised of a resorcinol-formaldehyde resin/styrene-butadiene-vinylpyridine latex optionally containing a styrene-butadiene rubber latex, and optionally containing a blocked isocyanate.

(22) In further accordance with this invention, said tire assembly is provided as a sulfur vulcanized composite and thereby a cured rubber tire. Such vulcanization may be conducted, for example, under conditions of elevated temperature and pressure as would be well known to those having skill in such art of rubber vulcanization.

(23) Representative of sulfur vulcanizable elastomers of said tire carcass to which said RFL adhesive is in contact may be comprised of, for example, cis 1,4-polyisoprene, cis 1,4-polybutdiene and styrene/butadiene copolymer rubbers.

(24) In additional accordance with the invention, the tire is further provided as a cured tire having been cured in a suitable mold at an elevated temperature.

(25) As indicated, the thin polymeric innerliner film laminate of the plurality film layers may have a thickness, for example, of from about 25 to about 200 microns. Alternately the thickness of the thin film laminate may range from about 50 microns to about 150 microns where the individual film layers may have varying individual film thicknesses as may be desired, for example, an individual film thickness of at least about 2 microns.

(26) The aforesaid thin innerliner film laminate for the barrier layer may have an oxygen permeability, for example, of less than 2010.sup.12 cc-cm/cm.sup.2.Math.sec.Math.cmHg. Desirably, the aforesaid polymeric innerliner film laminate may have an elongation, for example, of at least about 200 percent at about 23 C. As such, it is intended that, when used as the innerliner layer of the tire, the polymeric film is not intended to break during the tire shaping process.

(27) The rubber compositions for the rubber tire carcass layer (ply) can contain conventional rubber tire additives to provide a desired rubber property as would be applied by one having skill in the appropriate art. Such known and commonly used additive materials may include, for example, sulfur cure activators, retarders and accelerators, rubber processing oils, resins including tackifying resins, plasticizers, fatty acids, zinc oxide, waxes, antidegradant, antiozonants and peptizing agents.

(28) The uncured tire assembly can be molded and sulfur cured in a suitable tire mold at an elevated temperature and pressure conditions as would be appreciated and known to those having skill in such art.

(29) While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of Applicants' general inventive concept.