CA2021778A1 - Pneumatic vehicle tire - Google Patents

Abstract

TITLE OF THE INVENTION:
PNEUMATIC VEHICLE TIRE
ABSTRACT OF THE DISCLOSURE:
A pneumatic vehicle tire of rubber or rubber-like synthetic elastomeric material is provided.
The tire has a tread strip, a reinforcing belt, two sidewalls, a carcass that is anchored in beads by being looped about bead cores that are pull-resistant and/or resistant to compression, and respective profiled inner elements that are disposed radially outwardly of the bead cores. At least one of the elements of tread strip, sidewalls, profiled inner elements, beads, and rubber coatings for the belt, carcass, and bead cores is formed of a rubber mixture comprising 30 to 100% by weight of a nitrile-group-containing hydrocarbon rubber having a double bond proportion of no greater than 13/100 C atoms.

Description

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BACKGROUND OF THE INVENTION ~ -The present invention relates to a pneumatic vehicle tire of rubber or rubber-like synthetic elastomeric material, with the tire having a tread ~.
strip, a reinforcing belt, two sidewalls, a carcass that is anchored in beads by being looped about bead cores that are pull-resistant and/or reslstant to compression, and respective profiled inner elements that are disposed radially outwardly of the bead cores.
With heretofore known pneumatic vehicle tires, between 8 and 15 different rubber mixtures were used for the individual components of the tire in order to satisfy the different requirements made of these individual components. For example, with regard to the tread strip the primary consideration ls a hlgh reslstance to wear or abraslon, whereas for the sldewalls hlgh demands are set for the flexure and the reslstance to aglng: the proflled 20 lnner elements must have a great hardness ln order ~ ~;
to stlll the tlre ln the bead reglon.
It ls an obJect of the present lnventlon to provlde a pneumatlc vehlcle tlre where the propertles of the lndlvldual components are lmproved, and where the requlrements that are imposed can be satisfied with a low number of : ~.: . .. : . .. . .. . .

rubber mixtures.
BRIEF DESCRIPTION OF THE DRAWING
This ob~ect, and other obJects and advantages of the present invention, will appear more clearly ::. : . .. . -from the followlng specification in con~unction with examples of mixtures for the individual components and in con~unction with the accompanying schematic drawing, which is a cross~sectioned view of part of one exemplary embodiment of the pneumatic vehicle tire of the present invention.
SUMMARY OF THE INVENTION
The pneumatic vehicle tire of the present lnvention is characterized primarlly in that at least one of the element~ of tread strip, sidewalls, profiled inner elements, beads, and rubber coatings for the load-carrying means is formed of a rubber mixture comprising 30 to 100 .; .:. , :. .
parts, per 100 parts rubber, i.e. 30 to 100% by ~ ;
weight, with respect to the rubber fraction, of a nitrile-group-containing hydrocarbon rubber having a double bond proportion of no greater than 13/100 C atoms.
. :,, . :
The number of rubber mixtures that are required can be greatly reduced if all of the components tread strip, sidewalls, profiled inner ~ -.- ~
elements, beads, and rubber coatings for the load-:.~:. . .

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carrying means are formed of rubber mixtures comprlæing 30 to 100% by weight, of a nitrile~
group-containing hydrocarbon rubber having a double bond proportion of no greater than 13/100 C atoms.
In so doing, one can essentially get away with merely three different rubber mixtures, which in addition are also based on the same type of rubber.
One arrlves at three rubber mixtures if a first mixture is selected for the tread strip and sidewalls, a second mixture is used for the rubber or elastomeric coatings of the bead core, of the carcass, and of the belt, and a third mixture is provided for the beads and profiled inner elements. -The result i8 a tire that i8 distinguished by an ;
exceptional resistance to wear, resistance to high temperature, and resistance to oil. As a result of the inventlve use of HNBR or HNIR, an increased resistance to heat up to about 150 C is achieved.
The physical properties of the inventive mixtures remain nearly constant over an extremely wide temperature range. Finally, the high resistance to aging ls significant. Due to the extremely high air lmpermeability of the inventive mixtures, the conventionally required inner layer of butyl rubber can be eliminated. If the inventive mixtures are utilized in the tread strip and in the sidewall . . ,. . ~; .. ; , . ,, . , ~

regions, these regions can be designed ~ ~;
approximately 25% thinner than is possible with conventional tires due to the greatly improved propertles of the inventive rubber mixtures, this leads to a great savings in weight. Furthermore, with the inventive tire, some of the conventional fabric plies in the form of belt cover or cap plies or bead reinforcing lnserts, which up till now could not be altered, can be eliminated.
The nitrile-group-containing rubber can be produced, for example, by hydrogenation of nitrile butadiene rubber or nitrile isoprene rubber, or in -some other suitable manner. The rubber mixture for the indlvldual components of the tlre should contain 30 to 100~ by weight, and preferably 60 to 100% by weight, of the nitrile-group-containing rubber.
The sidewall mixture can be very absorptive and can have a rebound elasticity of less than 40%.
Further speclfic features of the present invention will be described in detail subsequently.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawing in detail, the - `
illustrated tire comprises a radial carcass 1 that ... . . . . .
is anchored in the beads 2 by being looped around --~
pull-resistant bead cores 3. At the sides, the tread strip 4 leads into sidewalls 5. A
aonventional reinforcing belt 6 is disposed radially outwardly of the radial carcass 1.
Disposed radially outwardly of the bead cores 3 are profiled inner elements 7. The rubber coatings of the carcass 1, the reinforcing belt 6, and the cores 3 are designated by the reference numeral 8.
Several examples of mixtures for the individual components of the tire will be described subseguently.
EXAMPLES OF MIXTURES FOR THE TREAD SURFACE
Pursuant to one preferred specific embodiment of the present invention, the mlxture for the tread surface contains a partially saturated rubber having nitrile groups and having a double bond proportion between 2/100 and 13/100 C atoms, and furthermore has a sulfur polymerization scheme.
This results in a rubber having an improved dynamic loading capacity. Wear or abrasion value~ of less ~ -~
than 50 mm3, and even less than 30 mm3, are achieved. ~ ;

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Example I (% by weight) 100 rubber HNBR
FEF black "
ester plasticizer 4 zina oxide 2 stearic acid ;~

3 magneslum oxide antioxidant ~-2 paraffin wax 10 1.7 sulfur ;~
2 cyclohexylbenzothiazolesulfenamlde 0.2 tetramethylthluram dlsulfide .
(thlram) . - . ~
Physlcal propertles: ;~
. . . ~, : ~ ~:, Strength: 22 MPa , --~
:::: : :,.
Breaklng elongation: 440 %
~. .: . ., :.: ::
Modulus 100 % : 3 MPa : . .. ... ..
Modulus 300 % : 14 MPa Hardness: 65 Shore A .- .
:: , . ...... ............ .
20 Wear (DIN): 30 mm3 : :
Rebound elastlclty: 33 %
Example II (% by welght) rubber HNBR : ,~
polybutadiene (80 % cis 1,4 GPF black zinc oxlde :
2 stearic acid ~ ,~
'''~'`' '` ~ :
- 6 ~

2 ~ 7 ~

4 antioxidant 3 magnesium oxide 8 ester plasticizer 2 sulfur 1.5 mercaptobenzothiazyl disulfide 0.5 tetramethylthiuram disulfide (thiram) Physical Properties Strength: 18.5 MPa 10 Breaking elongation: 440 % :`
Modulus 100 % : 4.3 MPa Modulus 300 % : 16.6 MPa Hardness: 71 Shore A
Wear: 22 mm3 Rebound elasticity: 38 %
Example III (% by weight) ~ ~-100 rubber HNBR
SRF blac~
~ " ~
zinc white 2 magnesium oxide .
2 stearlc acid ~, ester plasticizer -bis (tert-butylperozy isporopyl) benzene 2 trisallyl isocyanurate ' '` - .

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Physical Properties ~;~
Strength: 26 MPa Breaking elongation: 330 %
Modulus 100 % : 5.7 MPa Modulus 300 % : 24.5 MPa Hardness: 70 Shore A
Wear: 27 mm3 Rebound elasticity: 33 %
In example I, the rubber was entirely a partially hydrogenated nitrile rubber, and a polymerization scheme based on sulfur was used.
With thls mixture, a wear value of 30 m3 and a `~
rebound elasticity of 33% was achieved. ~ ;
In example II, a blend of 80% by weight HNBR -- -and 20% by weight polybutadiene are used as the rubber components, and a mixture is again vulcanized with a sulfur polymerization scheme.
With regard to the physical propertles, in partlcular the extremely low wear value of 22 mm3~ ~ -20 should be noted. The rebound elasticity was 38%. -In example III, the rubber components were entirely HNBR, with the polymerization being effected via a peroxide polymerization scheme. A ;
wear value of 27 mm3 and a rebound elasticity of 33% resulted.
It should be noted that with regard to the - 8 - `

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preceding three examples, HNIR could have been used instead of HNBR for the rubber components. In addition, it is, of course, possible to provide rubber components whereby the nitrile-group-containing saturated or partially saturated hydrocarbon rubbers HNBR and HNIR are blended with other rubbers.

EXAMPLES OF THE MIXTURE FOR THE SIDEWALL
Pursuant to one preferred specific embodiment, 10 the sidewall mixture contains a partially saturated -rubber having nitrile groups and having a double -bond proportion between 2/100 and 13/100 C atoms, and furthermore has a sulfur polymerization scheme. -In so dolng, a rubber having an lmproved dynamic ;
loadlng capabillty ls achleved. Wear or abrasion `~
values of less than 50 mm3, and even less than 30 mm3, were achleved.
Example IV (% by weight) 100 rubber HNBR : :.
SRF black 7 sulfonic acid ester plasticizer zinc oxide 2 stearic acid 3 magnesium oxide antioxldant 2 paraffln wax 2 ~ ~ ~, r~

2.0 sulfur 0.1 tetramethylthiuram disulflde (thiram) 1.5 mercaptobenzothiazyl disulfide Physical Properties Strenth: 15 MPa ~ .
Breaking elongation: 510 %
Modulus 100 % : 1.5 MPa Modulus 300 ~ : 5.2 MPa 10 Hardness: 55 Shore A . .-Wear: 70 mm3 . .'.` ~
Rebound elasticity: 65 % ~ -Example V (% by weight) . ,~
rubber HNBR
polybutadiene (80% cis 1,4-) GPF black zlnc oxide -2 stearic acid 4 antioxidant :~
3 magnesium oxide 8 ester plasticizer 2 sulfur 1.5 mercaptobenzothiazyl disulfide -.-~
0.5 tetramethylthiuram disulfide ~
(thiram) ~ -:, .

- 10 - .'. '' . .

-~ ~ Cb ,~ r ~

Physical Properties Strength: 18.5 MPa Breaking elongation: 440 %
Modulus 100 % : 4.3 MPa Modulus 300 % : 16.6 MPa Hardness: 71 Shore A
Wear: 22 mm3 Rebound elasticity:38 %
In example IV, the rubber was entirely a -;-~
partially hydrogenated nitrile rubber, and a polymerlzation scheme on the basis of sulfur was used. ~!t;~
In example V, the rubber component was a blend of 80~ by weight HNBR and 20% by weight polybutadiene, and the mlxture was again vulcanized with a sulfur polymerization scheme. Wlth regard to the physical properties, of particular note is the extremely low wear value of 22 mm3. The ~ ~
rebound elasticity was 38%. This results in a ~ -highly absorptive sidewall mixture, and hence in a tire that has an increased dampening of tire noise and improved driving stability, an in particular and improved steering precision.
It should be noted that for the two preceding examples, the rubber component can also include ; --HNIR in place of HNBR. Furthermore, it is, of - 1 1 - - : - ., " ' '~ ~ .~ .`.' -' ' ' .. : ~ :` '~ ' 2 ~
- ~ :

course, possible for the nitrile-group-containing saturated or partially saturated hydrocarbon .
rubbers HNBR and HNIR to be blended with further rubbers to form the rubber component.
EXAMPLES OF THE MIXTURE FOR THE BEAD AND/OR -~
PROFILED INNER ELEMENT
Example VI (% by weight) . ~
100 rubber HNBR -~ .
GPF black zinc oxide 1 stearic acid 2 magnesium oxide .
4 antioxidant ~ ~
2 paraffin wax ~ ::
1.7 sulfur 1.5 mercaptobenzothiazyl disulfide ~ :
0.5 tetramethylthluram disulfide ;
(thlram) Physical Properties 20 Strength: 23.5 MPa Breaking elongation: 470 %
Modulus 100 ~ : 3.1 MPa Modulus 300~ : 12.3 MPa :-Hardness: 80 Shore A ~ ~.
~" ., ' - 12 - -: : : :
.: ' ~: :

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Example VII (% by weight) 100 rubber HNBR -FEF black ester plasticizer ; ;~
2 zinc oxide 2 stearic acid 3 antioxidant 7 magnesium oxide 1 paraffin wax 106 bi~ (tert-butylperoxy isopropyl) benzene 2 trisallyl isocyanurate : ~ -"~ ~:
Physical Properties ~ : -Strength: 21.2 MPa ~ :
Breaking elongation:380 %
Modulus 100 % : 4.2 MPa Modulus 300 % :18 MPa Hardness: 73 Shore A
Example VIII (% by weight) ;
20 80 rubber HNBR
SBR
FEF black . ;~
ester plasticlzer . . :-2 zinc oxide .
2 stearic acid 3 antioxldant `~-- 13 ~
.-~.,...., ~-..-.-'',- ~-'`'`, .,~ : .

7 magnesium oxide ., ~ . . -~ . .
1 paraffin wax ~ -6 bis (tert-butylperoxy isopropyl) 2 trisallyl isocyanurate In example VI, the rubber component was .
entirely a partially hydrogenated nltrile rubber, . ~-and a po'ymerization scheme based on sulfur was used. ~he mlxture had a hardness of 80 Shore A.
In example VII, a peroxide polymerization scheme was used, and the mixture was ad~usted to a hardness of 73 Shore A.
In example VIII, the rubber component was a blend of 80% by weight HNBR to 20% by weight parts styrene-butadiene rubber. And the mlxture was agaln vulcanlzed using a peroxide polymerization scheme. Essentially the same physlcal properties resulte~ as with example VII.
It should be noted that with the preceding three examples, HNIR could be used in the rubber ~ .
component in place of HNBR. Furthermore, it is, of course, possible to use a blend of the nitrile-group-containlng saturated or partially saturated . - -.
. : . ~-:.-:
hydrocarbon rubbers HNBR and HNIR with further rubbers as the rubber component; thls is particularly applicable where a peroxide ;~
polymerization scheme is used. -- 14 - ``~ ~
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For mixtures pursuant to the heretofore known -~
state of the art, it is generally necessary to use phenolic resins in order to obtain the required hardness. However, phenolic resins have the drawback that the rubber remalns permanently elongated when lt ls overstressed. Thls drawback ls avolded wlth the inventlve mlxtures, whlch contain no phenollc resins. A further advantage of the present invention ls a very high resistance to aging as well as improved residual compression :
strain values. The rubber component of the mixture for the bead and/or proflled inner element should be 30 to 100% by weight, and preferably 60 to 100 by weight, HNBR or HNIR.
. ~
EXAMPLES OF THE RUBBER MIXTURE FOR RUBBER COATINGS

OF LOAD-CARRYING MEANS

Example IX (% by weight) 100 rubber HNBR

SRF black -~ -20 5 zinc oxide -~

1 stearic acld : .: ,: :; -;
1 magnesium oxide `~ ;

2 antioxidant : . - .: , .. .
2.0 sulfur `

0.1 tetramethylthiuram dlsulflde (thiram) - -~

1.5 mercaptobenzothiazyl disulfide - 15 ~
: . -: . -~':
~'.' '-~'~' :
' ,.`' ' .

~ . - : . . . . . .

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...

.. ... ~ ~ -Physical Propertles Strenth: 18 MPa :
Breaking elongation:450 %
Modulus 100 % : 2.6 MPa Modulus 300 % : 12.4 MPa Hardness: 64 Shore A ~ :
Permeabillty to air:10-17 m2/Pa.s .
Example X (% by weight) rubber HNBR
10 20 NR :
; ~: :. . ~ . .:
SRF black ~:
zinc oxide I stearic acid 1 magnesium oxide 2 antioxidant .~
2.0 sulfur -0.1 tetramethylthiuram disulfide .. :.:~
(thiram) 1.5 mercaptobenzothiazyl disulfide In example IX, the rubber component was .
entirely a partially hydrogenated:nitrile rubber, -::: , ~
and a polymerization scheme based on sulfur was ~:~
used. Wlth this mlxture, a permeability to air of about 10-17 m2/Pa~s was achieved.
In example X, the rubber component was a blend ~ :
of 80% by weight HNBR and 20% by weight natural - 16 - ~ :
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. .

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. .. , :. ~ . . . . ....

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rubber, and the mixture was again vulcanized ~ -utilizing a sulfur polymeri7atlon scheme.
Essentially the same physical properties were ~ -achieved as with example IX. ~;
It should be noted that with the preceding two examples, HNIR can be used in the rubber component ln place of HNBR. Furthermore, it ls, of course, posslble to use a blend of the nltrlle-group~
contalnlng saturated or partlally saturated 10 hydrocarbon rubbers HNBR an HNIR with further ; -rubbers as the rubber component.
As a consequence of the inventive use of HNBR `
or HNIR, a universal mixture is obtained for rubber ~ ;
coatings for the embedment of load-carrying inserts - ~
for components that are used to construct a tire. - -In contrast to heretofore known rubber coatlngs, -wlth the present inventlon a decldedly lmproved dynamic loading capacity and an improved reslstance to aging are obtalned. Furthermore, an lncreased thermal resistance to about 150 C ls achleved.
The physlcal propertles of the lnventlve mlxtures : ., :
remaln nearly constant over an extremely wlde temperature range. Due to the extremely hlgh lmpermeabllity to alr, when the lnventive mlxture is used as the rubber coatlng for the carcass, the heretofore conventional butyl rubber inner layer ~ ~;

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. ~ -.. . . . ..

can be eliminated.
Pursuant to one preferred specific embodiment of the present invention, the rubber mixture of the ;
rubber coating contains a partially saturated rubber having nitrile groups and having a double bond proportion between 2/100 and 13/100 C atoms, and furthermore has a sulfur polymerization scheme.
In so doing, a rubber having a still further improved dynamic loading capacity is obtained. Air permeability values (~T) of approximately 10-17 m2/Pa~ 8 are obtained.
The nitrile-group-containing rubber can, for `;; -example, be produced by hydrogenating nitrile-butadiene rubber or nitrile-isoprene rubber, or in some other manner. The mixture for the rubber coating should contain 30 to 100% by weight, and --preferably 60 to 100% by weight, of this rubber relative to the total amount of rubber.
The present invention is, of course, in no way restricted to the specific disclosure of the specification, examples, and drawing, but also encompasses any modifications within the scope of the appended claims.

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Claims (11)

1. In a pneumatic vehicle tire of rubber or rubber-like synthetic elastomeric material, with said tire having a tread strip, an elastomeric-coated reinforcing belt, two sidewalls, an elastomeric-coated carcass that is anchored in beads by being looped about elastomeric-coated bead cores that are pull-resistant and/or resistant to compression, and respective profiled inner elements that are disposed radially outwardly of said bead cores, the improvement wherein:
at least one of said elements of tread strip, sidewalls, profiled inner elements, beads, and elastomeric coating for said reinforcing belt, bead cores, and carcass is formed of a rubber mixture comprising 30 to 100% by weight, of a nitrile-group-containing hydrocarbon rubber having a double bond proportion of no greater than 13/100 C atoms.

2. A pneumatic vehicle tire according to claim 1, in which all of said named elements are formed of rubber mixtures comprising 30 to 100% by weight of a nitrile-group-containing hydrocarbon rubber having a double bond proportion of no greater than 13/100 C atoms.

3. A pneumatic vehicle tire according to claim 2, which comprises only three different rubber mixtures, namely a first mixture for said tread strip and sidewalls, a second mixture for said elastomeric coatings of said bead cores, carcass, and belt, and a third mixture for said beads and profiled inner elements.

4. A pneumatic vehicle tire according to claim 1, in which said nitrile-group-containing rubber is selected from the group consisting of HNBR and HNIR.

5. A pneumatic vehicle tire according to claim 1, in which the entire tread strip is formed of said rubber mixture comprising 30 to 100% by weight of a nitrile-group-containing hydrocarbon rubber; and in which said tread strip has a thickness that is equal to approximately 75% of the thickness of conventional tread strips.

6. A pneumatic vehicle tire according to claim 1, in which said sidewalls have a thickness that is equal to approximately 75% of the thickness of conventional sidewalls.

7. A pneumatic vehicle tire according to claim 1, in which said sidewall mixture is highly absorptive and has a rebound elasticity of less than 40%.

8. A pneumatic vehicle tire according to claim 1, in which at least one of the mixtures of said beads and said profiled inner elements is free of phenolic resins.

9. A pneumatic vehicle tire according to claim 1, in which said elastomeric coating of said carcass has a permeability to air (RT) of approximately 10-17 m2/Pa.s; and in which said tire is a tubeless tire having no conventional inner layer.

10. A pneumatic vehicle tire according to claim 1, in which said rubber mixture comprises 60 to 100% by weight, per 100 parts rubber, of a nitrile-group-containing rubber.

11. A pneumatic vehicle tire according to claim 1, in which said rubber has a double bond proportion of between 2/100 and 13/100 C atoms.