HK1159218A - Rubber articles subjected to repeated deformation and compositions for making the same - Google Patents

Description

Rubber article subjected to repeated deformation and composition for producing same

The present invention claims priority from U.S. provisional application serial No. 61/088,827 filed on 14.8.2008, incorporated herein by reference.

Technical Field

Embodiments of the present invention relate to a vehicle air spring (air spring) and an elastomeric composition from which it is made.

Background

Air springs or air-spring suspension devices (pneumatic suspension devices) have long been used to isolate road disturbances from vehicles, seats or cabs. Air springs, which are components of vehicle suspensions, support the load or mass (mass) of the vehicle at each axle. Typically, each axle of a vehicle supports a mass component or load carried by the axle in conjunction with an air spring. In addition, there are auxiliary air springs that provide comfort to the driver in and around the driver's cabin or cab. In an air spring, a large amount of gas, usually air, is enclosed in a flexible container (flexible container). When the air spring is compressed (jounce travel), the gas pressure within the air spring increases; when the air spring extends (rebound travel), the gas pressure in the air spring decreases. Road disturbances are absorbed by this compression and extension of the air springs, mainly as a function of work (w ═ jfdx). Air springs are often designed to have a specific spring rate or spring constant, thereby controlling the vibration and rebound characteristics for the intended use and for comfort.

Since the air spring undergoes numerous cycles between compression and extension, the air spring must include a flexible and durable closed container for the gas. Typically, these closed containers are referred to as bellows or air bags (airsleeves) and are made of cord reinforced rubber compositions. The reinforcement in the cord reinforced rubber composition may be a fabric or metal, and the cord fabric may be, but is not limited to, a natural or synthetic material.

Over time and under operating stress, the material properties of the air bag will change. Eventually, cracks may form and become sufficiently large to challenge the integrity of the air bag, requiring replacement. Accordingly, there is a need in the marketplace for an air spring having an air bag with improved crack resistance.

Disclosure of Invention

In one or more embodiments, the present invention provides an air spring having an air bladder, wherein at least one layer of the air bladder comprises a vulcanization product of an elastomer and syndiotactic 1, 2-polybutadiene.

In one or more embodiments, the present invention provides a method of producing an air spring air bag, the method comprising mixing an elastomer, syndiotactic 1, 2-polybutadiene, and a curing agent in a masterbatch to form a rubber composition, forming the rubber composition into the shape of an air bag, and curing the rubber composition.

In one or more embodiments, the present invention provides an air spring having air cells wherein at least one layer of the air cells has a rubber component comprising an elastomer and syndiotactic 1, 2-polybutadiene.

Drawings

FIG. 1 is a perspective view of an exemplary air spring according to one or more embodiments of the present invention.

FIG. 2 is a perspective view of an exemplary air spring according to one or more embodiments of the present invention.

Fig. 3 is a cross-sectional view of an exemplary air bag showing its layered structure.

Detailed Description

Figures 1 and 2 show two typical designs of air springs. In FIG. 1, a bidirectional cylindrical air spring assembly is generally indicated by the numeral 10. The bi-directional cartridge air spring assembly 10 includes a flexible air bladder 12. The bead plate 14 is bent into the air bag 12 to form an airtight seal between the bead plate 14 and the air bag 12. Similarly, the end cap 16 is pressed (mold) onto the flexible airbag 12 to form an airtight seal between the end cap 16 and the airbag 12. The end cap 16 of the air bag 12 is secured to the piston 18 by mechanical means known in the art including, for example, piston bolts (not shown). The piston 18 provides a surface for the flexible air bag 12 to advance during the compression (vibration) stroke. The dual cartridge air spring assembly 10 may optionally include a bumper (damper) 20 to support the vehicle when there is no air in the air spring or during extreme road disturbances. Enclosed within the air bag 12 is a volume of gas 22. Stud bolts (stud)24 and holes 26 are used to secure the bi-directional cartridge air spring assembly 10 to a mounting surface (not shown) of an automobile.

Figure 2 illustrates a (dual) convoluted air spring assembly generally indicated by the numeral 30. Convolute air spring assembly 30 includes a flexible air bladder 32. The bead plate 34 is bent to the air bag 32 to form an airtight seal between the bead plate 34 and the air bag 32. A strap 36 is secured to the air bag 32 between the bead plates 34. Convolute air spring assembly 30 may optionally include a bumper 38 to support the vehicle when there is no air in the air spring or during extreme road disturbances. Enclosed within the air bag 32 is a volume of gas 40. Blind nuts, including 42 and other blind nuts (blindnut) not shown, are used to secure the convoluted air spring assembly 30 to a mounting surface (not shown) of the automobile.

For both air spring assemblies 10 and 30, airbags 12 and 32 are made of cord reinforced rubber and may be composed of several layers, as shown in the cross-sectional view of exemplary airbag 52 in FIG. 3. The reinforcement in the cord reinforced rubber composition may be a fabric or metal, and the cord fabric may be, but is not limited to, a natural or synthetic material. The exemplary air bag 52 is characterized by a "two ply" construction and includes four layers including: an inner liner 54, a first ply 56, a second ply 58, and an outer tire (out cover) 60. The inner liner 54 and outer tire 60 may comprise calendered rubber. The first ply 56 comprises a single ply layer of cord reinforced rubber having cords of a particular bias cut angle. The second ply 58 comprises a single ply of fabric reinforced rubber laid opposite the bias cut angle of the first ply 56 with the same bias cut angle.

While the present invention is described in the context of an air bag and air spring for an automotive suspension, those skilled in the art will appreciate that the teachings disclosed are general and that the present invention has application in other fields related to the field of air springs. Other areas may include, for example, air springs for seats, air springs for supporting truck cabs, air springs for buses, and the like.

One or more embodiments of the present invention are directed to rubber compositions, which may also be referred to as vulcanizable compositions, for use in the manufacture of one or more layers of an air spring air bag. These vulcanizable compositions include a vulcanizable elastomer, syndiotactic 1, 2-polybutadiene, and optionally other ingredients known to be included in rubber compositions for one or more layers used to make air bags. These rubber compositions can be manufactured and cured into air bags and ultimately assembled into air springs by employing techniques known in the art.

In one or more embodiments, vulcanizable elastomers, which may also be referred to as rubbers, include those polymers that can be cured (also referred to as vulcanized) to form an elastomeric composition of the material.

As will be appreciated by those skilled in the art, exemplary elastomers include natural rubber, synthetic polyisoprene, polybutadiene, polyisobutylene-co-isoprene, polychloroprene, poly (ethylene-co-propylene), poly (styrene-co-butadiene), poly (styrene-co-isoprene-co-butadiene), poly (ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, polyurethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof.

In particular embodiments, the rubber comprises a polymer derived from the polymerization of a halogenated diene and optionally a monomer copolymerizable therewith. A common halogenated diene is 2-chloro-1, 3-butadiene, also known as chloroprene. Monomers copolymerizable with chloroprene include sulfur and 2, 3-dichloro-1, 3-butadiene. Homopolymers of chloroprene are commonly referred to as polychloroprene. For the purposes of this description, a rubber derived from chloroprene copolymerized with monomers copolymerizable therewith may be referred to as a polychloroprene copolymer.

In one or more embodiments, the polychloroprene or polychloroprene copolymer employed in the practice of the present invention is characterized by a Mooney viscosity (ML at 100 ℃)₁₊₄) Is at least 25, in other embodiments at least 40, in other embodiments at least 60, in other embodiments at least 80, in other embodiments at least 100. In these or other embodiments, the polychloroprene or polychloroprene copolymer is characterized by a Mooney viscosity (ML at 100 ℃)₁₊₄) Less than 150, in other embodiments less than 130, in other embodiments less than 110, in other embodiments less than 80, in other embodiments less than 60, and in other embodiments less than 50. In a particular embodiment, the polychloroprene or polychloroprene copolymer is characterized by a Mooney viscosity (ML at 100 ℃)₁₊₄) From about 100 to about 120, and in other embodiments from about 41 to about 51.

In one or more embodiments, blends of different polychloroprene or polychloroprene copolymers can be employed to achieve a desired balance of properties. These differences may be based on comonomer content and/or viscosity of the polymer.

Examples of desirable polychloroprene or polychloroprene copolymers are particularly usefulIs available from DuPont Performance Elastomers (Wilmington, DE) in Neoprene^TMObtained under the series designations "WD" and "WRT". Neoprene is considered^TMWD and WRT and Neoprene^TMThe G-type phase is relatively resistant to crystallization and is a copolymer of chloroprene and 2, 3-dichloro-1, 3-butadiene. Neoprene^TMWD shows a Mooney viscosity of 100-120 (ML at 100 ℃)₁₊₄) Range, simultaneous neopene^TMWRT shows a Mooney viscosity (ML at 100 ℃ C.) of 41 to 51₁₊₄) And (3) a range.

Syndiotactic 1, 2-polybutadiene, which may be simply referred to as syndiotactic polybutadiene, comprises a crystalline thermoplastic diene resin having a stereoregular structure in which side chain vinyl groups are alternately located on the opposite side as compared to the main chain of the polymer. In one or more embodiments, the syndiotactic 1, 2-polybutadiene is a homopolymer of 1, 3-butadiene monomer.

In one or more embodiments, the syndiotactic polybutadiene may be characterized by a weight average molecular weight of at least 80kg/mol, in other embodiments at least 90kg/mol, and in other embodiments at least 100 kg/mol. In these or other embodiments, the syndiotactic polybutadiene may be characterized by a weight average molecular weight of less than 250kg/mol, in other embodiments less than 220kg/mol, and in other embodiments less than 200 kg/mol. In one or more embodiments, the weight average molecular weight of the syndiotactic polybutadiene may be determined by using Gel Permeation Chromatography (GPC) with polystyrene standards.

In these or other embodiments, the syndiotactic polybutadiene may be characterized by a number average molecular weight of at least 60kg/mol, in other embodiments at least 70kg/mol, and in other embodiments at least 80 kg/mol. In these or other embodiments, the syndiotactic polybutadiene may be characterized by a number average molecular weight of less than 200kg/mol, in other embodiments less than 180kg/mol, and in other embodiments less than 160 kg/mol. In one or more embodiments, the number average molecular weight of the syndiotactic polybutadiene may be determined by using GPC with polystyrene standards.

In one or more embodiments, the syndiotactic polybutadiene is characterized by a melting temperature (Tm) of at least 60 ℃, in other embodiments at least 70 ℃, and in other embodiments at least 90 ℃. In some or other embodiments, the syndiotactic polybutadiene is characterized by a melting temperature of less than 130 ℃, in other embodiments less than 120 ℃, and in other embodiments less than 110 ℃. In one or more embodiments, the syndiotactic polybutadiene may be characterized by a glass transition temperature (Tg) of at least-40 deg.C, in other embodiments at least-20 deg.C, and in other embodiments at least 0 deg.C. In one or more embodiments, these temperatures (Tm and Tg) can be determined according to ASTM D3418.

In one or more embodiments, the syndiotactic polybutadiene may be characterized by a 1, 2-linkage content (also referred to as vinyl content) of at least 70%, in other embodiments at least 80%, in other embodiments at least 85%, in other embodiments at least 90%, in other embodiments at least 95%, and in other embodiments at least 98%.

In one or more embodiments, the syndiotactic polybutadiene is characterized by a syndiotacticity of at least 60%, in other embodiments at least 70%, in other embodiments at least 80%, in other embodiments at least 90%, in other embodiments at least 95%, and in other embodiments at least 98%.

In one or more embodiments, the syndiotactic polybutadiene may be characterized by a density of at least 750kg/m³In other embodiments at least 800kg/m³And in other embodiments at least 850kg/m³And in other embodiments at least 900kg/m³. In these or other embodiments, the syndiotactic polybutadiene may be characterized by a density of less than 1100kg/m³And in other embodiments less than 980kg/m³And in other embodiments less than 950kg/m³And in other embodiments less than 910kg/m³. At one endIn one or more embodiments, the density of syndiotactic polybutadiene may be determined in accordance with ASTM D1505.

In one or more embodiments, the syndiotactic polybutadiene may be characterized by a crystallinity of at least 5%, in other embodiments at least 10%, and in other embodiments at least 15%. In these or other embodiments, the syndiotactic polybutadiene may be characterized by a crystallinity of less than 50%, in other embodiments less than 40%, and in other embodiments less than 30%.

Particularly useful varieties of syndiotactic polybutadiene are available from JSR Corporation (Japan) under the trade names JSR RB810, JSR RB820, JSR RB830, and JSR RB 840.

In addition to the above ingredients, the vulcanizable compositions of the invention may optionally include other additives including, but not limited to, factice (face), carbon black, silica, stearic acid, metal oxides, antioxidants, polyethylene waxes, plasticizers, or other ingredients as desired.

In one or more embodiments, the vulcanizable compositions of the invention may include a particular factice or vulcanizate that is low in oil swell. These ointments reduce the toughness (compound neutral) of the compound and allow higher liquid plasticizer levels. The ointment may also accelerate the introduction of the filler and increase the grinding efficiency. Suitable oil creams are commercially available from Akrochem Corporation (Akron, OH) under the Akrofax trade name.

In one or more embodiments, the vulcanizable compositions of the invention may include carbon black. Carbon black is essentially pure elemental carbon in colloidal particle form produced by incomplete combustion or thermal decomposition of gaseous or liquid hydrocarbons under controlled conditions. Carbon black may be added to the vulcanizable composition as a reinforcing filler to achieve the desired balance of processability, hardness, and tensile or tear properties. In general, any conventional carbon black or blends thereof useful for compounding rubber-based air bag formulations are suitable for use in the present invention. Particularly useful carbon black grades include those meeting the properties of ASTM N550 and ASTM N762.

In one or more embodiments, the vulcanizable compositions of the invention may include silica. Useful forms of silica (silicon dioxide) include crystalline silica and amorphous silica. Crystalline forms of silica include quartz, tridymite, and cristobalite. Amorphous silica may be present when the silicon and oxygen atoms are arranged in an irregular pattern as determined by X-ray diffraction. In one or more embodiments, the silica is precipitated silica. In these or other embodiments, fumed silica is employed. Commercially available forms of silica are available from PPG Industries, inc. (Monroeville, PA), Degussa Corporation (Parsippany, NJ) and j.m. huber Corporation (Atlanta, GA). One commercially available product that may be used is RubbersilRS-150, characterized by a BET surface area of 150m²(ii) per gram, tap density (tapped density) of 230 g/liter, pH (5% aqueous suspension) of 7, SiO₂The content of Na is 98%₂SO₄Content 2% and Al₂O₃The content is 0.2%.

In one or more embodiments, the vulcanizable compositions of the present invention may include stearic acid. Stearic acid (octadecanoic acid) is a waxy solid and has the formula C₁₈H₃₆O₂. Stearic acid is particularly effective as a processing aid in minimizing grinding and calender roll sticking.

In one or more embodiments, the vulcanizable compositions of the invention may include a metal oxide, such as magnesium oxide (MgO) or zinc oxide (ZnO). The primary role of the metal oxide in the neoprene composition is to neutralize trace amounts of hydrogen chloride that may be released by the polymer during processing, vulcanization, heat aging or use (service). By removing hydrogen chloride, the metal oxide prevents autocatalytic decomposition, resulting in greater stability. The metal oxide may also participate in the crosslinking process by accelerating the reaction rate of elemental sulfur with the unsaturated rubber.

In one or more embodiments, the vulcanizable compositions of the present invention may include an antioxidant. A useful bisphenol-based antioxidant is Vulkanox BKF which is not discolored. Vulkanox BKF is commercially available from LANXESS (levirkusen, Germany).

In one or more embodiments, the vulcanizable compositions of the invention may include a low viscosity polyethylene wax. Low viscosity polyethylene waxes are release agents or antiblocking agents. Useful low viscosity polyethylene waxes are available under the trade name Akrowax PE-100 from Akrochem Corporation (Akron, OH).

In one or more embodiments, the vulcanizable compositions of the invention may include a wax. Waxes are processing aids and act as mold release agents.

In one or more embodiments, the vulcanizable compositions of the invention may include a plasticizer. A useful plasticizer is DOS (dioctyl sebacate) available under the trade name Polycizer DOS from hartick Standard (Akron, OH).

In one or more embodiments, the vulcanizable compositions of this invention may be prepared using compatibilizers to improve the blending of the neoprene and syndiotactic polybutadiene. Exemplary compatibilizers can be synthesized by reacting a low molecular weight amine-functionalized polymer with a low molecular weight neoprene or halogenated polymer.

In one or more embodiments, the vulcanizable compositions of the invention include a curing agent or cure package (cure package). The curing package includes a sulfur-based compound and may also include other optional ingredients. Exemplary cure packages include sulfur, TMTM, and zinc oxide, although other possible cure packages will be known to those skilled in the art.

Sulfur, which may or may not be soluble in the elastomer, may be used. An exemplary sulfur is crystalx OT 20, a polymeric sulfur that is insoluble in the elastomer. At the vulcanization temperature, the Crytex OT 20 depolymerizes to soluble sulfur and behaves similarly to what is traditionally referred to as "rubber specific sulfur" and promotes crosslinking of the polymer molecules. Crystex OT 20 is commercially available from Flexsys (Akron, OH).

TMTM or tetramethylthiuram monosulfide are cure accelerators that increase the cure rate by catalyzing the addition of sulfur chains to the rubber molecule. TMTM is commercially available from Western Reserve Chemical Corporation (Stow, OH).

The zinc oxide acts as a cure activator in the presence of sulphur, one or more accelerators and unsaturated rubber to help promote the formation of sulphur cross-links during vulcanization.

Antidegradants protect the final product vulcanizate against damaging external influences such as oxidation, ozone, heat and dynamic stresses. A suitable antidegradant is Vulkanox MB2, also known as 4-and 5-methyl-2-mercaptobenzimidazole (MMBI), and is commercially available from LANXESS (levirkusen, Germany).

Another suitable antidegradant is Wingstay 100, which is a mixed diaryl-p-phenylenediamine antidegradant. Wingstay 100 is commercially available.

Another suitable antidegradant is IPPD, or N-isopropyl-N' -phenyl-p-phenylenediamine. IPPD is available under the trade name Santoflex IPPD by Flexsys (Akron, OH).

Another suitable antidegradant is 6PPD, or N- (1, 3-dimethylbutyl) -N' -phenyl-p-phenylenediamine. 6PPD is available via Flexsys (Akron, OH) under the trade name Santoflex 6 PPD.

In one or more embodiments, the vulcanizable compositions used in the practice of this invention include a sufficient amount of vulcanizable rubber to achieve an air bag useful in air spring technology. In one or more embodiments, the total vulcanizable composition of the material includes at least 35 wt.% vulcanizable rubber, in other embodiments at least 40 wt.%, and in other embodiments at least 45 wt.%. In one or more embodiments at least 80%, in other embodiments at least 90%, and in other embodiments at least 95% of the rubber component of the vulcanizable rubber composition comprises polychloroprene or polychloroprene copolymers.

In one or more embodiments, the vulcanizable compositions of the invention include at least about 5 parts by weight, in other embodiments at least 8 parts by weight, and in other embodiments at least 10 parts by weight (pbw) of syndiotactic polybutadiene per 100 parts by weight rubber (e.g., total rubber). It is understood that parts by weight per 100 parts by weight of total rubber component may be referred to as phr. In one or more embodiments, the vulcanizable rubber composition includes less than about 50phr, in other embodiments less than about 30phr, in other embodiments less than about 20phr, and in other embodiments less than about 15phr of syndiotactic polybutadiene.

In certain embodiments, the vulcanizable rubber composition of the invention is free of factice. In one or more embodiments, the vulcanizable rubber composition may include at least about 2phr ointment, in other embodiments at least about 4phr, and in other embodiments at least about 8 phr. In one or more embodiments, the vulcanizable rubber composition may include less than about 20phr, in other embodiments less than about 15phr, and in other embodiments less than about 12phr of factice.

In one or more embodiments, the vulcanizable rubber composition may include at least about 20phr, in other embodiments at least about 30phr, and in other embodiments at least about 40phr of carbon black. In one or more embodiments, the vulcanizable rubber composition may include less than about 100phr, in other embodiments less than about 75phr, and in other embodiments less than about 50phr of carbon black.

In one or more embodiments, the vulcanizable rubber composition may include at least about 15phr, in other embodiments at least about 20phr, and in other embodiments at least about 25phr of silica. In one or more embodiments, the vulcanizable rubber composition may include less than about 250phr, in other embodiments less than about 200phr, in other embodiments less than about 90phr, and in other embodiments less than about 80phr of silica.

Those skilled in the art will be able to select appropriate amounts of the various components that can be used based on the ultimate desired properties sought within the air bag of the air spring. Likewise, one skilled in the art will be able to select the appropriate amount of curing agent and supplemental curing agent to achieve the desired level of cure.

The rubber composition used to prepare the one or more layers of the airbag in accordance with the present invention can be prepared by conventional means using conventional rubber compounding equipment such as Brabender, banbury, woner-fleiderer, bow knife mixers, two-roll mills, or other mixers suitable for forming a viscous, relatively uniform admixture. The mixing technique depends on various factors such as the particular type of polymer, filler, processing oil, wax, and other ingredients used. In one or more embodiments, the ingredients may be added together in one stage. In other embodiments, ingredients such as syndiotactic polybutadiene, carbon black, etc. may be charged first, followed by addition of the rubber. In other embodiments, a more conventional manner may be employed in which the rubber is added first, followed by the addition of the other ingredients. In even other embodiments, the rubber may be added simultaneously with the syndiotactic polybutadiene.

When an internal mixer is used, dry or powdered materials such as carbon black can be added first, followed by the addition of processing aids, and finally the neoprene (such mixing can be referred to as a back-mixing technique).

The mixing period generally ranges from about 2 to 10 minutes. In certain embodiments, incremental steps may be used whereby the rubber and a portion of the ingredients are added first, with the remaining ingredients being added in additional increments. In other embodiments, a portion of the rubber may be added over the other ingredients. In other embodiments, the rubber and syndiotactic polybutadiene are added together. In one or more embodiments, two-stage mixing may be employed.

Syndiotactic polybutadiene and rubber may be added near the beginning of the mixing cycle. In one or more embodiments, syndiotactic polybutadiene is included prior to the addition of the cure package.

The masterbatch discharge temperature can be set at about 100 + -10 deg.C due to the melting point of syndiotactic polybutadiene.

Near the end of the mixing cycle and at lower temperatures, a cure package (sulfur, accelerators, activators, etc.) may be added to prevent premature crosslinking of the neoprene chains.

After mixing, the rubber composition may then be formed into a sheet by calendering or combined with textile or metallic reinforcing cords. The rubber compositions of the present invention can also be formed into various types of articles using other techniques such as extrusion.

In one or more embodiments, the rubber composition of the present invention includes syndiotactic polybutadiene having discrete domains in the polychloroprene or polychloroprene copolymer. It is believed that these domains are formed because the syndiotactic polybutadiene is immiscible with polychloroprene or a polychloroprene copolymer. Nevertheless, the rubber compositions of the invention still have advantageous qualities. By selecting a syndiotactic polybutadiene having the disclosed melting temperature, the syndiotactic polybutadiene can be dispersed in neoprene without employing high mixing temperatures that may cause scorching of the polychloroprene or polychloroprene copolymer.

The vulcanizable rubber composition of the present invention can be formed into an air bag of an air spring by employing conventional techniques for making and manufacturing air springs.

In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. However, the examples should not be construed as limiting the scope of the invention. Therefore, for an understanding of the scope and breadth of the present invention, reference should be made to the following claims.

Examples

Two were prepared according to the examples of Table IThe parts of the air bag rubber composition, unless otherwise specified, are by weight. The first rubber composition does not contain syndiotactic polybutadiene. The second rubber composition comprises a rubber having a 1, 2-linkage content of about 92%, a melting temperature of about 95 ℃, and a density of about 906kg/m³Syndiotactic polybutadiene having a crystallinity of about 15 to 30% and a molecular weight of about 120 kg/mol. Polychloroprene I and polychloroprene II are copolymers of chloroprene and 2, 3-dichloro-1, 3-butadiene. The Mooney viscosity of polychloroprene I is about 100-120 and the Mooney viscosity of polychloroprene II is about 41-51.

TABLE I

Rubber composition	1	2
			Composition (I)

Polychloroprene I	50	45
			Polychloroprene II	50	45
Syndiotactic polybutadiene		10
			Ointment cake	10	10
N550	45	45
			Stearic acid	0.5	0.5
Magnesium oxide	4	4
			Paraffin wax	2	2
DOS	20	20
			Total of	181.5	181.5
Crystex OT-20	1	1
			DOTG	1	1
TMTM	1	1
			Zinc oxide	5	5
Wingstay 100 (diaryl PPD)	1.5	1.5
			ODP	2	2
Total of	193.0	193.0

The results of the various physical properties tested are set forth in table II.

TABLE II

Rubber composition	1	2
			Results
MDR2000(153 ℃, final material)
			ML(kg·cm)	1.2	1.1
MH(kg·cm)	10.4	10.1

Ts2 (minutes)	7.7	6.0
			Ts5 (minutes)	16.3	11.2
Tc50 (minutes)	14.6	10.0
			Tc90 (minutes)	44.0	33.1
Mooney (100 ℃, final material)
			ML1+4(MU)@100℃	39.1	33.9
Micro dumbbell draw (23 ℃, finished, unaged)
			Maximum pressure (MPa):	17.3	13.8
50% modulus (MPa):	0.9	1.1
			100% modulus (MPa):	1.8	2.4
200% modulus (MPa):	4.8	6.0
			300% modulus (MPa):	8.3	10.0
% strain at final fracture:	663.9	456.3
			toughness (MPa):	59.4	32.5
micro dumbbell draw (100 ℃, finished, unaged)
			Maximum stress (MPa):	8.8	7.0
50% modulus (MPa):	0.8	0.8
			100% modulus (MPa):	1.5	1.7
200% modulus: (MPa)：	3.7	4.2
			300% modulus (MPa):	6.1	6.9
% strain at final fracture:	433.8	303.7
			toughness (MPa):	18.2	9.5

various modifications and alterations that do not depart from the scope and spirit of this invention will become apparent to those skilled in the art. The present invention is not limited to the illustrative embodiments set forth herein.

Claims (17)

1. An air spring having an air bag, wherein at least one layer of the air bag comprises a vulcanization product of:

an elastomer; and

syndiotactic 1, 2-polybutadiene.

2. The air spring of claim 1, wherein the elastomer comprises polychloroprene or a polychloroprene copolymer.

3. The air spring of claim 2, wherein said polychloroprene copolymer is a copolymer of chloroprene and 2, 3-dichloro-1, 3-butadiene.

4. The air spring of claim 3, wherein said copolymer has a Mooney viscosity (ML at 100 ℃) of 100-120₁₊₄)。

5. The air spring of claim 4, wherein the copolymer further comprises a second copolymer of chloroprene and 2, 3-dichloro-1, 3-butadiene having a Mooney viscosity (ML at 100 ℃) of 41 to 51₁₊₄)。

6. The air spring of claim 1, wherein said syndiotactic 1, 2-polybutadiene has a melting temperature of at least 60 ℃ to less than 130 ℃.

7. The air spring of claim 1, wherein said syndiotactic 1, 2-polybutadiene has a melting temperature of at least 90 ℃ to less than 110 ℃.

8. The air spring of claim 1, wherein said syndiotactic polybutadiene is characterized by a 1, 2-linkage content of at least 70% to less than 90%.

9. The air spring of claim 1, wherein said syndiotactic polybutadiene is characterized by a syndiotacticity of at least 60% to less than 90%.

10. A method of producing an air spring airbag, the method comprising: mixing an elastomer, syndiotactic 1, 2-polybutadiene, and a curing agent into a masterbatch to form a rubber composition;

forming the rubber composition into the shape of an air cell; and

curing the rubber composition.

11. An air spring having an air bag, wherein at least one layer of the air bag has a rubber composition consisting of:

an elastomer; and

syndiotactic 1, 2-polybutadiene.

12. The air spring of claim 11, wherein said elastomer comprises at least one polymer of chloroprene.

13. The air spring of claim 12, wherein the at least one polymer comprises at least one copolymer of chloroprene and 2, 3-dichloro-1, 3-butadiene.

14. The air spring of claim 13, wherein the at least one copolymer comprises a first copolymer of chloroprene and 2, 3-dichloro-1, 3-butadiene having a mooney viscosity (ML at 100 ℃)₁₊₄) 100-.

15. The air spring of claim 14, wherein the at least one copolymer comprises a second copolymer of chloroprene and 2, 3-dichloro-1, 3-butadiene having a mooney viscosity (ML at 100 ℃)₁₊₄) Is 41-51.

16. The air spring of claim 11, wherein said syndiotactic polybutadiene is characterized by a 1, 2-linkage content of at least 70% to less than 90%.

17. The air spring of claim 11, wherein said syndiotactic polybutadiene is characterized by a syndiotacticity of at least 60% to less than 90%.