KR20040041658A - Structurally supported resilient tire and materials - Google Patents

Abstract

The present invention includes an improved non-air tire, and in particular a shear layer for non-air tires, the shear layer comprising an elastomeric composition having a metal salt of carboxylic acid. The shear layer preferably comprises a diene elastomeric composition having a metal salt of carboxylic acid. In one embodiment of the invention, the metal salt of carboxylic acid is zinc acrylate or zinc dimethacrylate. In one embodiment of the present invention, the metal salt of carboxylic acid is zinc diacrylate or zinc dimethacrylate, and a peroxide curing agent is used.

Description

Structurally supported resilient tires and materials

Pneumatic tires have been the solution of choice for vehicle mobility for centuries. Pneumatic tires obtain their mechanical properties considerably due to the action of internal air pressure in the tire cavities. The response to the inflation pressure provides a suitable strength for the belt and carcass parts.

Good pressure retention is necessary to obtain the best performance from the pneumatic tire. Inflation pressures below those specified by the manufacturer can cause loss of fuel economy. Moreover, conventional pneumatic tires can be used very limitedly after complete loss of inflation pressure. Many tire shrinkages have been proposed for continued vehicle mobility after a complete loss of air pressure from the tire. Some solutions for tires that may be punctured are pneumatic tires that add sidewall reinforcement to allow the sidewall to act as a support member of the load during the shrinking process. Another attempt to provide the ability to run even with holes is essentially to use annular reinforcement bands in the tire crown portion. In these solutions, the strength of the crown portion is produced in part from the inherent properties of the annular reinforcement band and in part from the response to inflation pressure. Another solution relies on an additional internal support structure attached to the wheel.

Tires designed to operate without the benefit of inflation pressure require neither pressure retention nor pressure regulation. However, structurally supported resilient tires, such as solid tires or other elastomeric structures, have so far not provided the level of performance expected from conventional pneumatic tires. A structurally supported resilient tire solution that delivers pneumatic type performance is a welcome improvement.

Summary of the Invention

The present invention includes improved shear layers for non-air tires and, in particular, non-air tires, wherein the shear layer comprises an elastomeric composition comprising a metal salt of carboxylic acid. The shear layer preferably comprises a diene elastomeric composition comprising a metal salt of carboxylic acid, which is preferably cured with a peroxide curing agent. In one embodiment of the invention, the metal salt of carboxylic acid is zinc diacrylate or zinc dimethacrylate.

The present invention relates to the field of non-pneumatic tires.

1 is a cross-sectional view of a structurally supported resilient tire.

2A is a schematic showing ground reaction force for a reference homogeneous band.

2B is a diagram showing the ground reaction force for the annular band of the present invention.

3 is a cross-sectional view of another embodiment of a structurally supported resilient tire of the present invention having an accurate membrane.

4 is a cross-sectional view of another embodiment of a structurally supported resilient tire of the present invention having a undulated second membrane.

5 is a cross-sectional view of the transformation of the embodiment presented in FIG. 4.

6 is a cross-sectional view of the transformation of the embodiment presented in FIG. 4.

The present invention includes improved shear layers for non-air tires and, in particular, non-air tires, wherein the shear layer comprises an elastomeric composition comprising a metal salt of carboxylic acid. The shear layer preferably comprises a diene elastomeric composition comprising a metal salt of carboxylic acid, which is preferably cured with a peroxide curing agent. In one embodiment of the invention, the metal salt of carboxylic acid is zinc diacrylate or zinc dimethacrylate.

Structurally Supported Resilient Tires

Structurally supported resilient tires support their loads only through the structural properties of their crowns, sidewalls and bead portions, without support from internal air pressure. The tire may be a radial tire or a bias ply tire. An example of such a tire is described in WO 01/42033 published on June 14, 2001 (Michelin Recherche et Technique, S.A.).

Structurally supported resilient tires, ie the crown portion of the tire without sidewalls and bead portions, are represented as tread and reinforcing annular bands. The tire comprises a ground contact tread portion, a side wall portion extending radially from the tread portion and fixed to the bead portion adapted to maintain safety to the wheel during the rolling of the tire and an inner radially disposed reinforcement annular band of the tread portion. . The band includes an elastomeric shear layer, one or more first films attached to the inner radial extension of the elastomeric shear layer and one or more second films attached to the outer radial extension of the elastomeric shear layer. Should be. The membranes each have a longitudinal tensile modulus that is sufficiently greater than the shear modulus of the shear layer, thereby deforming the ground contact tread portion by an externally applied load, essentially from circular to flat, to maintain the essentially constant length of the membrane, The location can be created by shearing in the shear layer.

The following terms are defined as follows:

"Equatorial Plane" means a plane perpendicular to the axis of rotation of the tire passing through the centerline of the tie.

“Modulus” of an elastomeric material means secant tensile modulusof elasticity at 10% elongation (MA 10) measured according to ASTM Standard Test Method D412.

By "modulus" of the membrane is meant elastic tensile modulus upon stretching 1% in the circumferential direction multiplied by the effective thickness of the membrane. This modulus can be calculated by the following scheme 1 for the tire steel belt material. This modulus is represented by a prime (') mark.

"Shear modulus" of an elastomeric material means an elastic shear modulus and is defined to correspond to one third of the elastic secant tensile modulus measured at 10% elongation.

"Hysteresis" means power loss tangent measured at 25 ° C under 10% dynamic shear stress.

"Structurally supported" means that the tire bears the load without the support of gas inflation pressure.

All documents cited herein are incorporated by reference.

A structurally supported resilient tire is shown in FIG. 1. The tire 100 shown in FIG. 1 has a ground contact tread portion 110, sidewall portions 150 extending radially from the tread portion 110 and bead portions 160 at the ends of the sidewall portions. Bead portion 160 secures tire 100 to wheel 10. Tread portion 110, sidewall 150 and bead portion 160 define a hollow annular shape 105.

The reinforcing annular band is located radially inward of the tread portion 110. In FIG. 1, the annular band is a first film 130 having an elastomeric shear layer 120, reinforcement films 131 and 132 attached to the radially innermost extension of the elastomeric shear layer 120. And a second film 140 having reinforcement films 141 and 142 attached to the radially outermost extension of the elastomeric shear layer 120.

In one embodiment, the first film 130, layers 131 and 132, have essentially parallel cords oriented at an angle α with respect to the tire equator plane, and the cords of each layer have opposite orientations. That is, layer 131 is angle + α and layer 132 is angle -α. Similarly, for the second film 140, layers 141 and 142 essentially have parallel cords oriented at angles + β and -β, respectively, relative to the equator plane. In these cases, the code angle included between adjacent layers is twice the specified angle α or β. Angles α and β typically range from about 10 to about 45 degrees. However, the cords of the layer pairs in the film need not be oriented at the same and opposite angles to each other. For example, it may be desirable for the cord of layer pairs to be asymmetrical with respect to the tire equator plane.

The layers of the first membrane 130 and the second membrane 140 each comprise a cord reinforcement that is not necessarily broadened, with each cord incorporated into the elastomeric coating layers that make up the membranes 130 and 140. In the case of a tire composed of an elastomeric material, the membranes 130 and 140 are bonded to the shear layer 120 by vulcanization of the elastomeric material. Membranes 130 and 140 may be bonded to shear layer 120 by any suitable method of chemical or adhesive bonding or mechanical fixation.

The reinforcing members of layers 131-132 and layers 141-142 may be one of several materials, such as monofilaments or cords of steel, aramid or other high modulus textiles. As mentioned above, each cord of layers 131, 132, 141 and 142 is incorporated into an elastomeric coating layer, in one embodiment of the present invention, the shear modulus is about 7 MPa. In another embodiment of the present invention, the shear modulus of the elastomeric coating layer is 5-7 MPa. Since the shear modulus of the cladding layer is greater than the shear modulus of the shear layer 120, it is desirable to ensure that the strain of the annular band is produced primarily by the shear strain in the shear layer 120.

The relationship between the shear modulus G of the elastomeric shear layer 120 and the effective longitudinal tensile modulus E ′ _film of the _membranes 130 and 140 controls the deformation of the annular band under the applied load. The effective tensile modulus E ' _membrane of a membrane using a tire belt material can be measured by the following equation:

In Equation 1 above,

E _rubber is a secant tensile modulus of an elastomeric coating material,

P is the code face (cord centerline spacing) measured perpendicular to the code direction,

D is the cord diameter,

v is Poisson's ratio to the elastomeric coating material,

α is the code angle for the equatorial plane,

t is the rubber thickness between the cables of adjacent layers.

Note that the E ' _membrane is the elastic modulus of the membrane x the effective thickness of the membrane. In the case where the ratio of E ' _membrane / G is relatively low, the deformation of the annular band under load approximates that of the homogeneous band and creates a non-uniform ground contact pressure as shown in FIG. On the other hand, when the ratio of the E ' _film / G is sufficiently high, the deformation of the annular band under load is essentially due to the shear deformation of the shear layer without almost longitudinal extension or compression of the film. Thus, the ground contact pressure is substantially uniform as shown in FIG. 2B.

The ratio of the longitudinal tensile modulus of the membrane E 'membrane to the shear modulus G of the shear layer is at least about 100: 1, preferably at least about 1000: 1. For example, in the case of a membrane comprising a cord reinforcement layer using a 4 × 0.28 cord, the preferred shear modulus of the shear layer 120 is about 3 to about 20 MPa. More preferably, it is 3-10 Mpa, Most preferably, it is 3-7 Mpa. Repeated deformation of shear layer 120 during rolling under load causes energy dissipation due to the hysteretic properties of the materials used. Overall heat generation in the tire is a function of this energy dissipation and the thickness of the shear layer. Thus, in the tire design presented, the hysteresis of the shear layer should be specified to maintain a tire operating temperature of less than about 130 ° C. for tires in continuous use.

3, 4, 5 and 6 illustrate another embodiment of a structurally supported resilient tire according to the present invention. In FIG. 3, the tire 200 has an annular band comprising a tread portion 210 and a shear layer 220, a first film 230, and a second film 240. In FIG. 4, the tire 300 includes a wavy second film 340, a tread portion 310, a shear layer 320, a sidewall 350, a first film 330, a second film 340, and the like. Reinforcing layers 342, 341, 332, and 331. 4 is a preferred embodiment of the present invention. In FIG. 5, tire 400 includes corrugated second film 440, tread portion 410, shear layer 420, sidewall 450, first film 430, second film 440, and the like. Reinforcing layers 442, 441, 432, and 431. In FIG. 6, the tire 500 includes a wavy second film 540, a tread portion 510, a shear layer 520, a sidewall 550, a first film 530, a second film 540, and Reinforcing layers 542, 541, 532, and 531.

Suitable materials for the shear layer of the tire of the present invention

Suitable elastomer

The rubber used for the shear layer 120 may be a natural rubber or a synthetic rubber that can be cured by a metal salt of carboxylic acid and a peroxide curing system. Mixtures of these rubbers may also be used. As used herein, "rubber" and "elastomeric" are synonymous.

In one preferred embodiment of the invention, the shear layer comprises a diene elastomer.

A "diene" elastomer or rubber is, in a known method, an elastomer (i.e., homopolymer) that is at least partially produced from diene monomers (whether conjugated or not), monomers containing two carbon-carbon double bonds. Or copolymer).

Generally, “essentially unsaturated” diene elastomers are dieene elastomers produced at least in part from conjugated diene monomers having a content of at least 15% (mol%) of members or units of the diene (conjugated diene). It is to be understood as meaning a polymer.

Thus, diene elastomers, such as, for example, butyl rubber or copolymers of dienes with alpha olefins of the ethylene-propylene diene terpolymer (EPDM) type and the like, are not included in the preceding definition, and particularly "essentially saturated "Diene elastomers (diene original unit content is always low or very low, less than 15%).

Within the scope of "essentially saturated" diene elastomers, "fairly unsaturated" diene elastomers should be understood to mean in particular diene elastomers having a diene unit (conjugated diene) content of at least 50%.

These definitions are given and it should be understood that the following is more particularly meant by diene elastomers which can be used in the compositions according to the invention:

(a) homopolymers obtained by polymerization of conjugated diene monomers having 4 to 12 carbon atoms (eg, polybutadiene);

(b) copolymers (e.g., styrene-butadiene copolymers) obtained by copolymerization with one or more together conjugated dienes or one or more vinyl aromatic compounds having 8 to 20 carbon atoms;

(c) copolymers of isobutene and isoprene (butyl rubber), and also halogenated, especially chlorinated or brominated forms of this type of copolymer.

Suitable conjugated dienes are, in particular, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di (C ₁ -C ₅ alkyl) -1,3-butadiene (eg 2,3- Dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene) , Aryl-1,3-butadiene, 1,3-pentadiene and 2,4-hexadiene. Suitable vinyl aromatic compounds are, for example, styrene, ortho-, meta- and para-methylstyrene, commercially available mixtures "vinyltoluene", para-tertiary butylstyrene, methoxystyrene, chlorostyrene, vinylmethylene, di Vinylbenzene and vinylnaphthalene.

The copolymer in (b) may contain 99 to 20% by weight of diene units and 1 to 80% by weight of vinyl aromatic units. The elastomer may have a particular microstructure, which is, in particular, a function of the polymerization conditions used in the presence or absence of modifiers and / or randomizers and amounts of modifiers and / or randomizers. Elastomers can be, for example, statistical, sequential or micro sequential elastomers, and can be prepared in dispersions or solutions, which are coupled by coupling agents and / or starring agents or functionalizing agents. And / or may be starred or functionalized.

Polybutadiene is preferably suitable, in particular those having a 1,2-unit content of 4 to 80% or cis-1,4 content of at least 80%, polyisoprene, butadiene-styrene copolymers and in particular styrene Content of 5 to 50% by weight, more particularly 20 to 40% by weight, butadiene having a 1,2-bond content of 4 to 65% and a trans-1,4 bond content of 20 to 80%, butadiene Isoprene copolymers and especially isoprene-styrene copolymers having an isoprene content of 5 to 90% by weight and a glass transition temperature (“Tg” as measured according to ASTM D3418-82) of from -40 to -80 ° C; It is suitable that the styrene content is 5 to 50% by weight and the Tg is 25 to -50 ° C. In the case of butadiene-styrene-isoprene copolymers, the styrene content is 5 to 50% by weight, more particularly 10 to 40% by weight, the isoprene content is 15 to 60% by weight, more particularly 20 to 50% by weight, butadiene The content is 5 to 50% by weight, more particularly 20 to 40% by weight, the 1,2-unit content of the butadiene portion is 4 to 85% and the trans-1,4 unit content of the butadiene portion is 6 to 80% and In particular, the 1,2- + 3,4-unit content of the isoprene portion is 5 to 70%, and the trans-1,4 unit content of the isoprene portion is 10 to 50%, and Tg is -20 to -70. Butadiene-styrene-isoprene copolymers which are degrees Celsius are more common.

In summary, particularly preferably, the diene elastomers of the composition according to the invention are polybutadiene (BR), polyisoprene (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers It is selected from the group of fairly unsaturated diene elastomers made.

When a copolymer is used, it is preferred from the group consisting of butadiene-styrene copolymer (SBR), butadiene-isoprene copolymer (BIR), isoprene-styrene copolymer (SIR) and isoprene-butadiene-styrene copolymer (SBIR). Is chosen.

Also more preferably, the diene elastomer is selected from the group consisting of natural rubber, synthetic cis-1,4 polyisoprene and mixtures thereof. These synthetic cis-1,4 polyisoprene preferably have a ratio (mol%) of cis-1,4 bonds of 90% or more, more preferably 98% or more.

Of course, the compositions of the present invention may contain a single diene elastomer or a mixture of several diene elastomers, wherein the diene elastomers or elastomers are airborne rather than certain types of synthetic elastomers that are not diene elastomers or even non-elastomeric It may be used in combination with, for example, a thermoplastic polymer.

Metal salts of carboxylic acids

The carboxylic acid is an unsaturated carboxylic acid. In one aspect of the invention, the carboxylic acid is selected from the group consisting of methacrylic acid, ethacrylic acid, acrylic acid, cinnamic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and mixtures thereof. Preferred carboxylic acids include acrylic acid and methacrylic acid.

The metal may comprise a metal selected from the group consisting of sodium, potassium, iron, magnesium, calcium, zinc, barium, aluminum, tin, zirconium, lithium, cadmium, cobalt and mixtures thereof. Zinc is preferred.

Preferred metal salts include zinc dimethacrylate and zinc diacrylate (Sartomer Co., Inc., "New Metallic Coagents for Curing Elastomers", April 1998). Other suitable acrylates are described in Sartomer Co., Inc., Sartomer Application Bulletin, May 1998, "Chemical Intermediates-Design Unique Polymers with Sartomer's Specialty Monomer", and Sartomer Co., Inc., Sartomer Application Bulletin, October 1999 , "Glass Transition Temperature of Sartomer Products".

Peroxide

Peroxides that can be used to promote curing of the elastomer of shear layer 120 include, but are not limited to, di-cumyl oxide; Tertiary butyl cumyl peroxide; 2,5-dimethyl-2,5 BIS (tert butyl peroxy) hexyn-3; BIS (tert butyl peroxy isopropyl) benzene; 4,4-di-tert butyl peroxy N-butyl valerate; 1,1-di-tert-butyl peroxy-3,3,5-trimethylcyclohexane; Bis- (tert butyl peroxy) -diisopropyl benzene; Tert butyl perbenzoate; Di-tertiary butyl peroxide; 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane and the like [Sartomer Co., Inc., Sartomer Application Bulletin: Basic Principles of Peroxide-Coagent Curing of Elastomers ", April 1997, herein Incorporated by reference] The amount of peroxide curing agent included in the composition depends on the elastomer used and the solidification load, generally, this amount may range from about 0.5 to about 5.0 parts per 100 weight of elastomer. A more preferred range is about 0.5 to about 5.0 parts per 100 parts by weight of elastomer, per 100 parts of peroxide.

Ultraviolet, beta and gamma rays, azo compounds such as 2 ', 2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylpentanenitrile), 1,1'-azobis ( Other free radical generating compounds and mechanisms can also be used, such as cyclohexanecarbonitrile), disulfide (RS-SR) and tetragen (R ₂ NN = N = NR ₂ )).

Filler

Suitable fillers include carbon black, as well as inorganic fillers (“white fillers”) such as silica, alumina, aluminum hydroxide, clays, calcium carbonate, glass fibers, microspheres, polymeric fibers such as polyester, nylon or aramid fibers. This includes. Appropriate levels of fillers will be known to those skilled in the art after reading this specification.

<White filler>

White or inorganic fillers used as reinforcing fillers can, in the latter case, be combined with carbon black, for example, to constitute all or part of the entire reinforcing filler. In the present application, "reinforced inorganic filler" is a known method, whatever its color and its base (natural or synthetic), in contrast to carbon black and also referred to as "white" filler or often "transparent filler", It should be understood that it means inorganic or mineral fillers, and such inorganic fillers can reinforce the intended rubber composition in the manufacture of the tire without any means other than the intermediate coupling agent, in other words, it is conventional in its reinforcing function. It can replace tire grade carbon black filler.

In one aspect of the invention, the reinforcing inorganic filler is an inorganic filler in the form of silicon or aluminum or a mixture of both types of filler. The silicas (SiO ₂ ) used are reinforcing silicas known to those skilled in the art, in particular precipitated or pyrogenic silicas having both a BET surface area and a CTAB specific surface area of less than 450 m 2 / g, preferably 30 to 400 m 2 / g. When the present invention is used in the manufacture of tires with low rolling resistance, highly dispersible precipitated silica (preferably referred to as "HDS") is preferred, and "highly dispersible silica" is elastomeric in known methods. It is to be understood that it refers to silica having a substantial ability to dissolve and disperse in the matrix, which can be observed by methods known in the art by electron or optical microscopy. Non-limiting examples of such preferred highly dispersible silicas include silica BV3380 and Ultrasil 7000 (Degussa), silica Zeosil 1165 MP and 1115 MP [Rhodia], silica Hi-sil 2000 [manufactured by P.J. Industries, Inc. (PPG Industries, Inc.); 15272 Pittsburgh, Philadelphia], Silica Zeopol 8715 or 8745 [manufactured by G.M., 30327 Atlanta, Georgia. Hoover Corporation (JM Huber Corp.).

Reinforced alumina (Al ₂ O ₃ ) which is preferably used has a BET surface area of 30 to 400 m 2 / g, more preferably 60 to 250 m 2 / g, as described in EP-A 0 810 258 mentioned above. The average particle size is mostly 500 nm, more preferably 200 nm high dispersible alumina. Non-limiting examples of such reinforced alumina include, inter alia, alumina A125 or CR125 (Baikowski Intl. Corp., Charlotte, NC), APA-100RDX (Condea, Netherlands). [Condea Servo BV], Aluminoxide C (manufacturer: Degusa) or AKP-G015 (manufacturer: Sumitomo Chemical Co., Ltd., Osaka-fu, Japan). . The invention can also be practiced by using certain aluminum (oxide-) hydroxides as described in patent application WO 99/28376 as reinforcing inorganic fillers.

The physical state in which the reinforcing inorganic filler is present is non-material, whether it is powder, microbeads, granules or balls. Of course, “reinforced inorganic fillers” should also be understood to mean mixtures of different reinforcing inorganic fillers, in particular highly dispersible silica and / or alumina fillers as described above.

Reinforcing inorganic fillers can also be used in blends (mixtures) with carbon black. Suitable carbon blacks are certain carbon blacks, especially blacks in the form of HAF, ISAF and SAF commonly used in tires. The amount of carbon black present in the total reinforcing filler can vary widely.

In this specification, the BET specific surface area is described in "The Journal of the American Chemical Society", vol. 60, page 309, February 1938] is measured according to the method of Brunauer, Immett and Teller (BET method: the method of Brunauer, Emmet and Teller). CATB specific surface area is the external surface area determined by the method.

Coupling Agents Useful in the Present Invention

In the case of inorganic fillers such as silica, a coupling agent is necessary to bond the elastomer and the filler. The term "coupling agent" (inorganic filler / elastomer) is intended to provide a sufficient chemical and / or physical bond between the inorganic filler and the elastomer in a known manner [e.g. more than bifunctional, e.g., simple chemical formulas Coupling agents that are "YTX"; Wherein Y represents a functional group (“Y” group) capable of being physically and / or chemically bonded to the inorganic filler, such a bond being, for example, the silicon atom of the coupling agent and the hydroxy (OH) of the inorganic filler Can be formed between surface groups (eg surface silanol in the case of silica); X represents an elastomer and a functional group ("X" group) capable of being physically and / or chemically bonded, eg by a sulfur atom; T represents a hydrocarbon group that allows Y and X to be bonded].

The coupling agent may comprise, in particular known methods, Y groups active for inorganic fillers, but should not be fused with simple formulations to cover inorganic fillers that do not contain X groups active for elastomers.

Such coupling agents of various effects have been described in a great deal of literature and are well known to those skilled in the art. Indeed, in diene rubber compositions that can be used in the manufacture of tires, coupling agents known or easy to ensure effective bonding or coupling between silica and diene elastomers can be used, for example organosilanes, in particular There are polysulfide alkoxysilanes or mercaptosilanes, or polyorganosiloxanes containing the aforementioned X and Y groups.

Depending on the intended use, the nature of the elastomer used and the amount of inorganic reinforcing filler, one skilled in the art can control the amount of coupling agent in the compositions of the present invention.

Other substances

The rubber compositions according to the invention also contain plasticizers, pigments, antioxidants, vulcanization accelerators, extender oils, process aids, in addition to elastomer (s), reinforcing fillers, sulfur and one or more reinforcing white filler / elastomeric binder (s). And various other constituents and additives commonly used in rubber mixtures, such as one or more agents (such as alkoxy silanes, polyols and amines) for coating white reinforcing fillers.

Formulation

The rubber composition is usually prepared in an appropriate mixer using two successive manufacturing steps, a second step of mechanical treatment at lower temperatures followed by a first step of thermodynamic treatment at high temperatures. In the case of silica mixtures, a three step process can be used. One suitable mixer is a Banbury mixer (Farrel Corp., Ansonia, CT 06401).

The first step of the thermodynamic treatment (often referred to as the “non-generating step”) is to thoroughly mix the various components of the composition by kneading, with the exception of the reticulation (curing) system. Under the action of mechanical processing and high shear imposed on the mixer, it is carried out in a suitable kneading apparatus, such as an internal mixer or extruder, until the maximum temperature generally reaches 120 to 190 ° C, preferably 130 to 180 ° C.

This first step may itself comprise a single or several thermodynamic treatment steps, for example separated by one or more intermediate cooling steps. Various components of the composition, elastomer (s), reinforcing fillers and coupling agents and various other components (“additives”) thereof may be incorporated into the mixer in one or more steps during the first thermodynamic step, or optionally, various thermodynamic steps Can be mixed on the way. The overall duration of this thermodynamic treatment (typically 1 to 20 minutes, for example 2 to 10 minutes) is chosen depending on the particular operating conditions, in particular the maximum temperature chosen, the properties and volumes of the components, and importantly within the reaction. A good dispersion of the various components is obtained in the elastomeric matrix, so that the composition can be subjected to good processing first in the uncured state, and then after curing, a sufficient level of reinforcement by the reinforcing filler and its intermediate coupling agent. To ensure that

According to a preferred process embodiment of the invention, all of the basic constituents of the composition according to the invention, namely the reinforcing inorganic filler and its coupling agent (ii), are incorporated into the diene elastomer (i) during the first stage, called the non-production stage. That is, at least these different basic constituents are introduced into the mixer and kneaded in one or more steps, thermodynamically, until the maximum temperature reaches 120 to 190 ° C, preferably 130 to 180 ° C.

As an example, the first (non-generating) step is carried out in two successive steps of 1 to 5 minutes in a conventional internal blade mixer of the "Banbury" type with an initial tank temperature of around 60 ° C. First, an elastomer (or elastomers) is introduced, and then, for example, after one minute of kneading, the reinforcing filler and its coupling agent are introduced, and subsequently kneaded, for example, after one minute, vulcanized With the exception of the saponification system, various additives are added including possible auxiliary coatings or processing agents. When the apparent density of the reinforcing filler (or one of the reinforcing fillers, if some are used) is relatively low (eg in the case of silica), the latter is introduced and, optionally, some of its coupling systems. In order to facilitate its incorporation into the elastomeric matrix by dividing the introduction into the step, for example, half or even about three quarters of the filler is incorporated after one minute kneading and the remainder after two minutes kneading. desirable. Thus, the thermodynamic treatment is carried out until a maximum temperature, called a "dropping" temperature, is obtained, which is probably 135 to 170 ° C. The blocks of the mixture thus obtained are collected and cooled to a temperature below 100 ° C. After cooling, the second thermodynamic step is carried out in the same or different mixers in order to complement the heat treatment of the mixture and in particular to obtain a better dispersion of reinforcing fillers and, of course, stearic acid, anti-ozone wax, antioxidant, zinc oxide or Some additives, such as other additives, may be introduced, in whole or in part, into the mixer up to this second thermodynamic treatment step. The result of this first thermodynamic step is then followed by an external open mill at low temperatures (eg, 30-60 ° C.), and after the vulcanization system has been added, the entire composition is for several minutes, for example, 2 to Mix for 5 minutes (production stage).

The elastomer is first added to the mixer in the first non-production stage. Next, a filler (eg carbon black) is added and the material is dropped from the mixer. In the second step, the curing agent is added at low temperature. Metal salts of carboxylic acids can be added to the production or nonproductive mixing step.

In the case of a silica base composition, in the first step, a silica filler and a coupling agent (eg Si-69) are added and mixed for a time suitable to achieve coupling of silane and silica. Then, the mixture is added dropwise. The batch of silica-silane is then mixed with peroxides, metal salts of carboxylic acids such as zinc dimethacrylate and other additives. In addition, peroxides and additives such as zinc oxide may be added to the mill at low temperatures. The addition of at least 4 parts per 100 parts zinc stearate per 100 weight of elastomer reduces the adhesion of the mixture to the processing apparatus.

The final composition thus obtained is then calendered, for example, in the form of a film or sheet for characterization, in particular in the laboratory, or for example a rubber profile member used in the preparation of the shear layer of the invention. Extrude to form.

The reticulation (or curing) is generally carried out at a temperature of 130 to 200 ° C., preferably under pressure, in particular for a sufficient time that can vary depending on the curing temperature, the crosslinking system employed and the vulcanization reaction process of the composition, For example, it is carried out by a known method for 5 to 90 minutes.

In one aspect of the invention, the shear layer has an elastic shear modulus of about 3 to about 20 MPa. In another aspect of the invention, the shear layer has the following approximate modulus range.

3 to 5 MPa

6 to 8 MPa

9 to 11 MPa

12 to 14 MPa

14 to 16 MPa

17 to 20 MPa

3 to 7 MPa

3 to 10 MPa

11 to 20 MPa

We have found that different ranges of modulus have utility for different vehicle groups. The inventors found that resilient tires that are structurally supported for different vehicle groups have different requirements in terms of hysteresis, elasticity and cohesion. The inventors have found that by adding a resin to obtain sufficient shear modulus for conventional rubbers, a product lacking cohesion can be produced to act as a shear layer. That is, the shear layer is likely to tear. Conventional methods of increasing the cohesion of such rubber mixtures, such as increasing the sulfur content or adding more accelerators, can make the rubber weaker, less elastic and difficult to process. This mixture is also not suitable for the shear layer of the present invention. The present inventors are easy to process with the use of metal salts of acrylic acid and, in particular, zinc dimethacrylate and zinc diacrylate, can provide the modulus required for the shear layer for each vehicle group, and provide high elasticity and cohesive strength. It is said that a composition is produced that can have.

General Information

(1) The following is a general formulation of a shear layer according to the invention. This is referred to as "phr" (weight parts per 100 parts of elastomer or rubber). "ZDMA" means zinc dimethacrylate.

Elastomer 100phr

30 phr (10 to 60 phr) metal salt of carboxylic acid

1 phr (0.1 to 5 phr) peroxide

45 phr (30 to 70 phr) filler

(2) The following is a preferred formulation of the shear layer according to the present invention.

Natural rubber 100phr

30 phr (15 to 40 phr) zinc methacrylate or dimethacrylate

1 phr (0.5 to 2 phr) peroxide

45 phr (30 to 60 phr) filler

(3) The following is a formulation for a sports car. Sports cars are expected to reach high speeds (eg 150 miles / hr) with corresponding high hysteresis. The tires run low in deflection (ie, mainly on smooth roads and highways) and support only moderate loads (2 to 3 passengers, no load-perhaps 400 kg / tire). Such tires are "V" (149 m.p.h.); "W" (168m.p.h.) or "Y" (186m.p.h.) speed class. The following is the formulation for the shear layer.

Natural rubber 35 phr (30 to 65 phr)

65 phr (35 to 70 phr) polybutadiene

1 phr (0.5 to 2 phr) peroxide

50 phr (30 to 60 phr) carbon black (e.g. N650)

15 phr (10 to 20 phr) zinc dimethacrylate

(4) The following is a formulation for an industrial tire. Industrial tires (eg Boboat tires or tractor tires) can be used at low speeds (eg 5-10 m.p.h.) with high deflection (ie running on rocks) under high loads per tire (ie 1600 kg).

Therefore, the cohesion of the tire material is very important (the ability of the material to withstand splitting or tearing). This will probably require a large tread area facing the ground. The following is the formulation for the shear layer.

100 phr (80 to 100 phr) of natural rubber

Polybutadiene 0 phr (0 to 20 phr)

1 phr (0.5 to 2 phr) peroxide

Carbon black 0phr

45 phr silica (40 to 70 phr)

ZDMA 40 phr (20 to 50 phr)

(5) In the case of passenger vehicle tires, the tires should be at a suitable speed (e.g. 118 m.ph), under appropriate load (e.g. two adult passengers without luggage; about 400 kg / tire), with adequate deflection (i.e. Used on good roads). The following is the formulation for the shear layer.

80 phr (50 to 90 phr) of natural rubber

20 phr (10 to 50 phr) polybutadiene

1 phr (0.5 to 2.0 phr) peroxide

30 phr (30 to 60 phr) carbon black (e.g. N650)

ZDMA 35 phr (20 to 40 phr)

The invention will be better understood with reference to the following non-limiting examples.

Example 1

Elastomeric materials for the shear layer are prepared according to the present invention.

Control group 1 Control 2 Control group 3 Mixture 1 Mixture 2 Mixture 3 Mixture 4 Mixture 5 caoutchouc 35 35 100 35 80 100 100 100 Polybutadiene 65 65 65 20 20 Zeosil1165MP (silica) 62 45 45 45 N650 (carbon black) 65 65 50 30 X50S (silane combiner) 9.9 5.8 5.8 5.8 Peroxide (dicup 40C [40%]) 5 2.5 2.5 2.5 Zinc Dimethacrylate 15 35 40 40 40 ZnO 4 4 4 4 4 4 4

[Table shows parts by weight per 100 parts of elastomer or rubber]

[Highly dispersible silica "Zeosil 1165MP" in the form of micropearls; Manufacturer Rhodia (BET and CTAB: approximately 150-160 m 2 / g)

[N650 Carbon Black is available from 79008, Texas, Boger, Engineered Carbons, Engineered Carbons, Inc. and other suppliers]

[S169 is bis (3-triethoxysilylpropyl) tetrasulfide of formula {(C ₂ H ₅ O) ₃ Si (CH ₂ ) ₃ S ₂ } ₂ ; Trade name S169 (or X505 if supported in a content of 50% by weight relative to carbon black); Manufacturer: Degusa Corporation, Ridgefield Park, NJ]

Control group 1 Control 2 Control group 3 Mixture 1 Mixture 2 Mixture 3 Mixture 4 Mixture 5 Mooney Viscosity (1) 83 85 83 56 39 49 48 55 MA 10 (Mpa) (2) 12 10 12 16 21 10 17 21 MA 50 (Mpa) (3) 9.2 7.5 6.7 12.5 11.2 4.9 7.3 9.4 MA 100 (Mpa) (4) 9.6 6.6 6 Destruction 10 4 5.7 7.3 G '(5) under 10% shear strain 4.9 3.1 4 4.9 G '(5) under 40% shear strain Adhesive destruction 2.9 3.1 4.5 Tan δ at 10% shear (5) 0.045 0.046 0.077 0.041 Tan δ at 40% shear (5) Adhesive destruction 0.034 0.078 0.038 P60 (Rebound 60 °) 9 12.5 21 12 22 27 30 29 Elastic shear limit (%) 100 ℃ > 50% > 50% > 100% > 50% > 100% > 100% > 100% > 100% Cohesive Strain (MPa) 100 ° C (6) 14.8 7.4 9.9 14.8 14.9 13.3 Cohesion Force (MPa) 100 ℃ (7) 213 50 90 395 332 246 Dimensional Stability (8) 2 2 2 One One One One One Aging Stability (9) 3 2 3 One One One One One Concentration offered Corvette tourism Corvette Travel Industrial skid-steer military wheelchair Industrial skid-steer military wheelchair Industrial skid-steer military wheelchair

(1) ML (1 + 4) below 100 ° C. = low viscosity

(2) Tensile modulus at 23 ° C and 10% strain

(3) Tensile modulus at 23 ° C and 50% strain

(4) Tensile modulus at 23 ° C and 100% deformation

(5) 10hz, 100 ℃

(6) Scott ultimate stress at 100 ° C

(7) Scott ultimate strain at break at 100 ° C

(8) Relative (based on MTS), "1" is best and "3" is worst

(9) Relative, "1" is best and "3" is worst.

Dynamic properties are measured by MTS loading rig (MTS Systems Corp., Eden Prairie, 55344, Minnesota) at 10 hz in pure shear strain form.

Under tensile load, the force divided by the original area of the sample under compulsion is called stress (as presented above in units of mega Pascal). The dislocation (movement or stretching) of a material is called strain. Typically, the strain force is presented as a change in length divided by the original length, and the units are dimensionless. Modulus is the slope of the stress curve with respect to strain (vertical axis is stress, transverse axis is strain). The elastic shear modulus (G ') of a material is the ratio of the elastic (stage) stress to the strain and is related to the ability of the material to elastically store energy. The loss modulus (G ") of the material is the ratio of the viscous (from step) component to the shear strain and is related to the ability of the material to dissipate stress through heating. The ratio of these modulus (G '/ G") is It is defined as tan δ and represents the relative viscosity to the elastic dissipation or damping of the material. Lower tan δ values mean higher resilience and lower hysteresis.

G 'represents shear modulus (mega Pascal) and tan δ represents relative hysteresis of the material.

ML (1 + 4) numbers below 100 ° C. = low viscosity. This is a Mooney viscosity test performed using a large rotor. Warm up for 1 minute with stopping and spin for 4 minutes. The value is read at the end of 5 minutes.

MA10, MA50 and MA100 are tensile modulus tests at 10%, 50% and 100% elongation, respectively. These are measured using an Instron tensile tester (Instron Inc. Canton, MA 02101).

The tests for tan δ at 10% shear and 40% shear are described in MTS, Inc. It is performed using a test instrument (MTS Systems Corporation, Eden Prairie, MN 55344).

The P60 test is a hysteresis test that measures the rebound angle of the pendulum when a rubber sample is hit. The first five initial strikes are ignored and the next three strikes are measured.

Elastic shear limit tests are performed using an MTS tester. The sample is stretched until its stress / strain curve is out of the linear region.

In the Scott ultimate stress test, the sample is stretched until it breaks. Samples are drawn at a constant rate.

Dimensional stability tests are performed using an MTS tester.

An aging test is performed on an MTS instrument after the samples have been aged at 77 ° C. for 7, 14 or 28 days.

From the table together with fillers (such as carbon black or silica), the use of metal salts of carboxylic acids (ZDMA containing peroxides) by free radical generators can yield a series of properties superior to those of conventional rubber systems. It can be seen. That is, the present invention can achieve the best properties for the shear layer of structurally supported resilient tires, such as high modulus, high elasticity and high cohesive strength.

Various modifications of the invention will become apparent to those skilled in the art after reading the foregoing specification, the appended claims and the accompanying drawings. These modifications are meant to fall within the scope of the appended claims.

Claims (26)

A tread, a sidewall portion extending radially from the tread portion, and a bead portion located at the distal end of the sidewall, the annular band further comprising an inner radially disposed tread portion, wherein the annular band is an elastomeric shear layer A structurally supported resilient tire comprising a first film attached to the radially innermost extension of an elastomeric shear layer and a second film attached to the radially outermost extension of an elastomeric shear layer, A structurally supported resilient tire characterized by using a shear layer comprising an elastomeric composition having a metal salt of carboxylic acid. The tire of claim 1 selected from the group consisting of radial tires or bias ply tires. The tire of claim 1, wherein the elastomeric composition is selected from the group consisting of natural and synthetic elastomers and mixtures thereof. A tread, a sidewall portion extending radially from the tread portion, and a bead portion located at the distal end of the sidewall, the annular band further comprising an inner radially disposed tread portion, wherein the annular band is an elastomeric shear layer A structurally supported resilient tire comprising a first film attached to the radially innermost extension of an elastomeric shear layer and a second film attached to the radially outermost extension of an elastomeric shear layer, A structurally supported resilient tire using a shear layer comprising an elastomeric composition having a metal salt of carboxylic acid and wherein the elastomeric composition is selected from the group consisting of diene elastomers. The tire of claim 4, wherein the diene elastomer is selected from the group consisting of polybutadiene, polyisoprene, butadiene copolymers, isoprene copolymers and mixtures thereof. The tire of claim 4 wherein the elastomer is selected from the group consisting of natural rubber, synthetic polyisoprene, styrene-butadiene copolymers, butadiene-isoprene copolymers, isoprene-butadiene-styrene copolymers and mixtures thereof. The tire of claim 4 wherein the diene elastomer is selected from the group consisting of natural rubber, synthetic cis-1,4 polyisoprene and mixtures thereof. A tread, a sidewall portion extending radially from the tread portion, and a bead portion located at the distal end of the sidewall, the annular band further comprising an inner radially disposed tread portion, wherein the annular band is an elastomeric shear layer A structurally supported resilient tire comprising a first film attached to the radially innermost extension of an elastomeric shear layer and a second film attached to the radially outermost extension of an elastomeric shear layer, A structurally supported resilient tire using a shear layer comprising an elastomeric composition having a metal salt of carboxylic acid and wherein the carboxylic acid is selected from the group consisting of unsaturated carboxylic acids. The tire of claim 8, wherein the carboxylic acid is selected from the group consisting of methacrylic acid, ethacrylic acid, acrylic acid, cinnamic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and mixtures thereof. The tire of claim 1, wherein the metal of the metal salt is selected from the group consisting of sodium, potassium, iron, magnesium, calcium, zinc, barium, aluminum, tin, zirconium, lithium, cadmium, cobalt and mixtures thereof. A tread, a sidewall portion extending radially from the tread portion, and a bead portion located at the distal end of the sidewall, the annular band further comprising an inner radially disposed tread portion, wherein the annular band is an elastomeric shear layer A structurally supported resilient tire comprising a first membrane attached to the radially innermost extension of an elastomeric shear layer and a second membrane attached to the radially outermost extension of an elastomeric shear layer, A structurally supported resilient tire using a shear layer comprising an elastomeric composition having a metal salt of carboxylic acid and wherein the metal salt is selected from the group consisting of zinc diacrylate and zinc dimethacrylate. The tire of claim 1, wherein the elastomer further comprises a curing agent comprising a free radical generating composition. 13. The tire of claim 12, wherein the curing agent is selected from the group consisting of peroxides, azo compounds, disulfides and tetragens. The tire of claim 13, wherein the curing agent is peroxide. 15. The method of claim 14, wherein the peroxide is di-cumyl oxide; Tertiary butyl cumyl peroxide; 2,5-dimethyl-2,5 BIS (tert butyl peroxy) hexyn-3; BIS (tert butyl peroxy isopropyl) benzene; 4,4-di-tert butyl peroxy N-butyl valerate; 1,1-di-tert-butyl peroxy-3,3,5-trimethylcyclohexane; Bis- (tert butyl peroxy) -diisopropyl benzene; Tert butyl perbenzoate; Di-tertiary butyl peroxide; A tire selected from the group consisting of 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane and mixtures thereof. The tire of claim 1, wherein the elastic shear modulus of the elastomeric shear layer is about 3 to about 20 MPa. The tire of claim 1, wherein the elastic shear modulus of the elastomeric shear layer is about 3 to about 10 MPa. A tread, a sidewall portion extending radially from the tread portion, and a bead portion located at the distal end of the sidewall, the annular band further comprising an inner radially disposed tread portion, wherein the annular band is an elastomeric shear layer A structurally supported resilient tire comprising a first film attached to the radially innermost extension of an elastomeric shear layer and a second film attached to the radially outermost extension of an elastomeric shear layer, A structurally supported resilient tire using a shear layer comprising an elastomeric composition having a metal salt of carboxylic acid and wherein the elastic shear modulus of the elastomeric shear layer is about 3 to about 7 MPa. The tire of claim 1, wherein the ratio of the longitudinal tensile modulus of one of the membranes to the shear modulus of the shear layer is at least about 100: 1. The tire of claim 1, wherein the ratio of the longitudinal tensile modulus of one of the membranes to the shear modulus of the shear layer is at least about 1000: 1. A tread, a sidewall portion extending radially from the tread portion, and a bead portion located at the distal end of the sidewall, the annular band further comprising an inner radially disposed tread portion, wherein the annular band is an elastomeric shear layer A structurally supported resilient tire comprising a first film attached to the radially innermost extension of an elastomeric shear layer and a second film attached to the radially outermost extension of an elastomeric shear layer, Using a shear layer comprising an elastomeric composition having a metal salt of carboxylic acid, the shear layer comprising 100 phr of elastomer (a), about 10 to 60 phr of metal salt of carboxylic acid (b), and about 30 to 70 phr of filler (c) And about 0.5 to 2 phr of peroxide (d). The compound of claim 1, wherein the shear layer is selected from the group consisting of 100 phr of natural rubber (a), about 15 to 40 phr of zinc diacrylate and zinc dimethacrylate, and about 30 to 60 phr of filler (c). ) And about 0.5 to 2 phr of peroxide (d). The shear layer of claim 1, wherein the shear layer is selected from the group consisting of 30 to 65 phr of natural rubber (a), about 35 to 70 phr of polybutadiene (b), about 10 to 20 phr of zinc diacrylate and zinc dimethacrylate. A tire comprising compound (c), about 30 to 60 phr of carbon black (d) and about 0.5 to 2 phr of peroxide (e). The shear layer of claim 1, wherein the shear layer is selected from the group consisting of 80 to 100 phr natural rubber (a), about 0 to 20 phr polybutadiene (b), about 20 to 50 phr zinc diacrylate and zinc dimethacrylate A tire comprising compound (c), about 40 to 70 phr silica (d) and about 0.5 to 2 phr peroxide (e). The shear layer of claim 1 wherein the shear layer is selected from the group consisting of 50 to 90 phr of natural rubber (a), about 10 to 50 phr of polybutadiene (b), about 20 to 40 phr of zinc diacrylate and zinc dimethacrylate. A tire comprising compound (c), about 30 to 60 phr of carbon black (d) and about 0.5 to 2 phr of peroxide (e). The shear layer of claim 1 wherein the shear layer is selected from the group consisting of 80 to 100 phr of natural rubber (a), about 0 to 20 phr of polybutadiene (b), about 30 to 50 phr of zinc diacrylate and zinc dimethacrylate A tire comprising compound (c), about 30 to 70 phr silica (d) and about 0.5 to 2 phr peroxide (e).