DE102009044051A1 - Pneumatic vehicle tire i.e. commercial vehicle tire, has reinforcements embedded in rubber coating composition, where coating composition and/or padding and/or covering compositions exhibits rebound resilience of less than given percent - Google Patents

Abstract

The tire has metallic reinforcements embedded in a rubber coating composition and surrounded by padding and/or covering compositions. The coating composition and/or the padding and/or covering compositions exhibits rebound resilience of less than 35 percent at room temperature according to DIN 53 512. The coating composition and/or the padding and/or covering compositions contains emulsion polymerized styrene-butadiene copolymer, adhesive resin i.e. terpene phenol resin, natural rubber, silica, organic cobalt salt, zinc oxide and a resorcinol-formaldehyde adhesive system.

Description

The invention relates to a pneumatic vehicle tire, in particular commercial vehicle tires, with metallic reinforcing elements, which are embedded in a gumming mixture and, if necessary, surrounded by further cushioning and / or covering mixtures.

For the embedding of metallic strength in vehicle pneumatic tires, in particular brass-plated steel cord, special rubber compounds are used. In order to ensure the durability of the rubber-reinforcement composite, the embedding rubber mixture (rubber mixture) should have good adhesion to the reinforcements. In addition, the vulcanizates should have a high dynamic and mechanical resistance, in particular damage to the surrounding areas should be avoided by the ends of the reinforcement. Such damage can occur, for example, in the region of the belt edge of pneumatic vehicle tires when the tire is running through the ground contact surface. This leads to deformations on the tire, which can cause due to the different moduli of the materials rubber and strength carrier penetration of reinforcements into the surrounding rubber matrix. This effect is one of the main reasons for the formation of cracks on the belt edge of pneumatic vehicle tires. Due to the heavy load on commercial vehicle tires, the problem of cracks at the belt edge is particularly common in these tires.

In order to reduce the penetration of reinforcing materials into the surrounding rubber matrix at the edge of belts, it is known to provide further cushioning and / or covering mixing areas at the belt edges in the region of the tire shoulder, where particularly strong flexing and centrifugal forces act. These include upholstery and cover strips, which are arranged between and above the individual belt layers in the area of the tire shoulder. Also known as wraps, which are whipped around the belt edges, are known for this purpose.

The invention is based on the object to further reduce the formation of cracks on the belt edge of pneumatic vehicle tires.

The object is achieved according to the invention in that the gum mixture and / or the other abpolsterden and / or covering mixtures according to a rebound resilience at room temperature DIN 53 512 less than 35%.

The movements in the area of the belt edge occur in driving operation in fractions of seconds. The penetration of the reinforcing elements, in particular the steel cords, into the rubber matrix is comparable to a short energy pulse. The basic idea of the invention can be seen in the fact that it has been recognized that the greater the intensity of this energy pulse, the lower the load per unit volume. The risk of cracking is thus reduced. The inventive use of high-damping mixtures, d. H. Blends with low resiliency allow such rapid and efficient energy absorption by converting the energy into heat.

In order to keep the heat development, which occurs increasingly in the case of high-damping mixtures, as low as possible in the region of all inner components of the tire, only the gumming mixture and / or the further cushioning and / or covering mixtures have rebound resilience of less than 35%. The metallic reinforcement also contribute by their thermal conductivity to dissipate the heat in lower tempered areas.

The energy absorption is particularly effective and thus the risk of cracking is further reduced if the gum mixture and / or the other abpolsterden and / or covering mixtures according to a rebound resilience at room temperature DIN 53 512 less than 30%.

The low rebound resilience of the mixtures can advantageously be achieved by containing the corresponding mixtures 5 to 30 phr of at least one styrene-butadiene copolymer having a glass transition temperature T _g of more than -55 ° C, preferably more than -45 ° C.

The term phr used in this document (parts per hundred parts of rubber by weight) is the usual quantity in the rubber industry for mixture formulations. The dosage of the parts by weight of the individual substances is always based on 100 parts by weight of the total mass of all the rubbers present in the mixture.

The styrene-butadiene copolymers (SBR) may be both solution and emulsion polymerized types. Preferably, however, an emulsion-polymerized SBR is used, which leads to particularly low rebound resilience of the resulting mixtures.

Alternatively or additionally, the rebound resilience of the mixtures can also be reduced by the use of special adhesive resins, thereby reducing crack initiation at the belt edge. Adhesive resins are suitable for this purpose which have a melting point Mp of more than 90 ° C., preferably more than 100 ° C., and are used in amounts of from 2 to 10 phr, preferably from 3 to 8 phr.

As such tackifier resins, resins known in the rubber industry such as petroleum resins, colophony resins or phenol-formaldehyde resins may be used. However, particularly preferred is the use of a terpene-phenolic resin as an adhesive resin, which can be mixed well and effectively reduces cracking.

According to an advantageous development of the invention, the gumming mixture and / or the further padding and / or covering mixtures contain more than 60 phr, preferably more than 70 phr, of natural rubber. With this measure, the tearing properties of the mixtures can be further improved, i. H. their susceptibility to cracks and the rate of crack propagation is reduced.

In order to reduce the rebound resilience, it is further possible to meter in the gum mixture and / or the further padding and / or covering mixtures of silica in amounts of more than 6 phr, preferably more than 7 phr. This possibility is used in particular in so-called carbon black mixtures, which essentially only contain carbon black as filler.

The gum mixture and / or the other abpolsterden and / or covering mixtures may according to a preferred embodiment of the invention contain an organic cobalt salt for improving the rubber-metal adhesion. The cobalt salt is preferably used in amounts of from 0.2 to 2 phr. As cobalt salts z. For example, cobalt stearate, borate, borate alkanoates, naphthenate, rhodinate, octoate, adipate, etc. can be used. The improvement in rubber-to-metal adhesion also plays a role in the cushioning and / or covering compounds, since it is believed that in the manufacture of the tire and over its lifetime metallic strengthening members, especially their ends, come into contact with these compositions ,

To further improve the rubber-to-metal adhesion, the gum mixture and / or the other cushioning and / or masking mixtures contain at least 5 phr of zinc oxide.

The addition of a resorcinol-formaldehyde adhesive system of resorcinol and a formaldehyde donor, such. For example, hexamethoxymethylmelamine (HMMM) or hexamethylenetetramine (HEXA) may be included to improve adhesion in the topping compound and / or the other cushioning and / or masking mixtures.

The gum mixture and / or the other abpolsterden and / or covering mixtures, in addition to the rubber types already mentioned also other diene rubbers, such as. As polybutadiene or synthetic polyisoprene having.

As fillers, for example, carbon black and / or silica are used in conventional amounts.

The mixtures may contain, in addition to the substances mentioned, further customary additives in customary parts by weight. These additives include plasticizers, silane coupling agents, anti-aging agents such. N-phenyl-N '- (1,3-dimethylbutyl) -p-phenylenediamine (6PPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), 2,2,4-trimethyl-1, 2-dihydroquinoline (TMQ) and other substances, such as those from J. Schnetger, Encyclopedia of Rubber Technology, 2nd edition, Hüthig Book Verlag, Heidelberg, 1991, pp. 42-48 are known activators, such. For example, fatty acids (eg., Stearic acid), waxes and Mastikationshilfsmittel such. B. 2,2'-Dibenzamidodiphenyldisulfid (DBD).

The mixtures are crosslinked with sulfur and / or sulfur donors in the presence of vulcanization accelerators.

The preparation of the pneumatic vehicle tire according to the invention is carried out in the usual way. The gum mixture and / or the other padding and / or covering mixtures are In general, a basic mixture containing all constituents except for the vulcanization system (sulfur and vulcanization-influencing substances) is first mixed in one or more mixing stages and, subsequently, the finished mixture is produced by adding the vulcanization system. Subsequently, the mixture is processed further. For example, the steel cord for the belt of a pneumatic vehicle tire can be calendered with this mixture (belt rubberization). Also, the carcass and the bead cores can be gummed with this mixture. Furthermore, the belt cushions and / or belt cover strips and / or belt preparations may be formed from these mixtures.

The invention will now be explained in more detail with reference to comparative and exemplary embodiments, which are summarized in Tables 1 and 2.

Table 1 shows the blend compositions. For all of the mixture examples shown in Table 1, the amounts given are parts by weight based on 100 parts by weight of total rubber (phr). The comparative mixtures are marked with V, the mixtures according to the invention are marked with E. The mixtures 1 to 5 relate to silica mixtures, and mixtures 6 and 7 are carbon black mixtures.

Table 2 lists the vulcanizate properties determined for the various mixtures.

• • Shore-A-Härte bei Raumtemperatur gemäß DIN 53 505
• • Rückprallelastizität bei Raumtemperatur gemäß DIN 53 512
• • Zugfestigkeit bei Raumtemperatur gemäß DIN 53 504
• • Reißdehnung bei Raumtemperatur gemäß DIN 53 504
• • Spannungswerte (Modul) bei 100 und 300% Dehnung bei Raumtemperatur gemäß DIN 53 504
• • Bruchenergiedichte bestimmt im Zugversuch nach DIN 53 504 , wobei die Bruchenergiedichte die bis zum Bruch erforderliche Arbeit, bezogen auf das Volumen der Probe, ist
• • Stahlcordhaftung gemäß ASTM 2229/D1871 vor Alterung bei Raumtemperatur, Einbettlänge 12,5 mm, Auszugsgeschwindigkeit 125 mm/min, Messung der Kraft und der Bedeckung mit Gummi (0% = keine Bedeckung, 100% = vollständige Bedeckung), verwendeter Stahlcord: vermessingt, 3 × 0,20 + 6 × 0,35
• • Reißenergie pro verformtem Volumen bei Raumtemperatur gemäß High Speed Tear Energy Test nach DIN EN 10 045
• • Weiterreißwiderstand bei Raumtemperatur und 100°C nach Graves gemäß DIN 53515

Tabelle 1 Bestandteile Einheit 1(V) 2(E) 3(E) 4(E) 5(E) 6(V) 7(E) Naturkautschuk phr 80 80 80 80 80 100 100 BR^a phr 20 - - - - - - ESBR^b phr - 20 20 20 20 - - Ruß N326 phr - - - - - 60 60 Kieselsäure phr 55 55 55 55 53 - 8 Silan-Kupplungsagens^c phr 8 8 8 8 8 - - Zinkoxid phr 8 8 8 8 8 8 8 Weichmacher phr 3 3 - 3 3 3 1 Harz Gum Rosin^d phr 1,5 1,5 - 1,5 1,5 - - Phenolharz^e phr 1,5 1,5 - 1,5 1,5 1,5 - Terpen-Phenol-Harz^f phr - - 7 - - - 5 Alterungsschutzmittel phr 3 3 3 3 3 3 3 Cobaltstearat phr 1,5 1,5 1,5 1,5 1,5 1,5 1,5 Harz aus Resorcin und Formaldehydspender phr 5 3,5 3,5 3,5 5 6,2 5,6 Beschleuniger phr 1,6 1,6 1,6 1,6 1,6 0,75 1,0 Schwefel (mit 33 Gew.% Öl verstreckt) phr 5,8 5,8 5,8, 5,8 5,8 6,0 6,0 ^a cis-1,4-Polybutadien
^b ESBR, 49% Styrolanteil, 15% Vinylanteil, T_g = –27°C, Pliogum 1028, Goodyear Chemicals, USA
^c TESPT auf Ruß, 50/50
^d Gum Rosin C, Smp. 80–85°C, La union resinera, Spanien
^e Phenolharz, Smp. 90°C, Durez 29095, Sumitomo Bakelite, Belgien
^f Terpen-Phenol-Harz, Smp. 112°C, Sylvares TP300, Arizona Chemicals, USA Tabelle 2 Eigenschaften Einheit 1(V) 2(E) 3(E) 4(E) 5(E) 6(V) 7(E) Shore-A-Härte bei RT Shore A 75,9 75,8 78,4 74,5 74,7 81,6 81,0 Rückprallelastizität bei RT % 43,2 28,0 23,7 27,6 28,9 38,8 34,9 Zugfestigkeit bei RT MPa 20,8 22,1 20,5 21,7 21,9 19,0 20,3 Reißdehnung bei RT % 486 481 456 489 478 350 373 Spannungswert 100% MPa 3,1 3,4 3,6 3,2 3,4 4,3 4,2 Spannungswert 300% MPa 12,2 13,6 13,6 13,0 13,7 17,6 17,7 Bruchenergiedichte J/cm³ 40,4 43,3 38,6 42,7 42,9 27,0 31,3 Stahlcordhaftung ungealtert (Herausziehkraft) N 439 409 431 416 428 404 420 Stahlcordhaftung ungealtert (Bedeckung) % 98 93 96 92 94 98 98 Reißenergie pro verformtem Volumen bei RT MJ/m³ 4,86 5,63 6,02 6,39 5,46 3,27 4,00 Weiterreißwiderstand bei RT - 82 85 105 91 87 74 63 Weiterreißwiderstand bei 100°C - 51 52 63 50 49 53 61 Mixture preparation was carried out under standard conditions in a laboratory tangential mixer. Test specimens were prepared from all mixtures by vulcanization under pressure at 160 ° C. for 15 minutes, and the material properties typical of these rubber specimens were determined by the test methods indicated below.

• • Shore A hardness at room temperature according to DIN 53 505
• • rebound resilience at room temperature according to DIN 53 512
• • tensile strength at room temperature according to DIN 53 504
• • Elongation at room temperature according to DIN 53 504
• • Tension values (modulus) at 100 and 300% elongation at room temperature according to DIN 53 504
• • Breaking energy density determined in the tensile test DIN 53 504 wherein the fracture energy density is the work required to break, based on the volume of the sample
• • steel cord adhesion according to ASTM 2229 / D1871 before aging at room temperature, embedding length 12.5 mm, drawing speed 125 mm / min, measurement of force and covering with rubber (0% = no coverage, 100% = complete coverage), used steel cord: brass plated, 3 × 0.20 + 6 × 0.35
• • Tear energy per deformed volume at room temperature according to High Speed Tear Energy Test DIN EN 10 045
• • Tear resistance at room temperature and 100 ° C according to Graves according to DIN 53515

Table 1 ingredients unit 1 (V) 2 (E) 3 (E) 4 (E) 5 (E) 6 (V) 7 (E) natural rubber phr 80 80 80 80 80 100 100 BR ^a phr 20 - - - - - - ESBR ^b phr - 20 20 20 20 - - Carbon black N326 phr - - - - - 60 60 silica phr 55 55 55 55 53 - 8th Silane coupling agent ^c phr 8th 8th 8th 8th 8th - - zinc oxide phr 8th 8th 8th 8th 8th 8th 8th softener phr 3 3 - 3 3 3 1 Resin Gum Rosin ^d phr 1.5 1.5 - 1.5 1.5 - - Phenolic resin ^e phr 1.5 1.5 - 1.5 1.5 1.5 - Terpene phenolic resin ^f phr - - 7 - - - 5 Anti-aging agents phr 3 3 3 3 3 3 3 cobalt stearate phr 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Resin from resorcinol and formaldehyde donor phr 5 3.5 3.5 3.5 5 6.2 5.6 accelerator phr 1.6 1.6 1.6 1.6 1.6 0.75 1.0 Sulfur (stretched with 33% by weight of oil) phr 5.8 5.8 5.8 5.8 5.8 6.0 6.0 ^a cis-1,4-polybutadiene
^b ESBR, 49% styrene, 15% vinyl, T _g = -27 ° C, Pliogum 1028, Goodyear Chemicals, USA
^c TESPT on carbon black, 50/50
^d Gum Rosin C, Mp. 80-85 ° C, La union resinera, Spain
^e phenolic resin, mp 90 ° C, Durez 29095, Sumitomo Bakelite, Belgium
^f Terpene phenolic resin, mp 112 ° C, Sylvares TP300, Arizona Chemicals, USA Table 2 properties unit 1 (V) 2 (E) 3 (E) 4 (E) 5 (E) 6 (V) 7 (E) Shore A hardness at RT Shore A 75.9 75.8 78.4 74.5 74.7 81.6 81.0 Rebound resilience at RT % 43.2 28.0 23.7 27.6 28.9 38.8 34.9 Tensile strength at RT MPa 20.8 22.1 20.5 21.7 21.9 19.0 20.3 Elongation at RT % 486 481 456 489 478 350 373 Voltage value 100% MPa 3.1 3.4 3.6 3.2 3.4 4.3 4.2 Voltage value 300% MPa 12.2 13.6 13.6 13.0 13.7 17.6 17.7 Fracture energy density J / cm ³ 40.4 43.3 38.6 42.7 42.9 27.0 31.3 Steel cord adhesion unaged (pull-out force) N 439 409 431 416 428 404 420 Steel cord adhesion unaged (covering) % 98 93 96 92 94 98 98 Tear energy per deformed volume at RT MJ / m ³ 4.86 5.63 6.02 6.39 5.46 3.27 4.00 Tear resistance at RT - 82 85 105 91 87 74 63 Tear propagation resistance at 100 ° C - 51 52 63 50 49 53 61

From the table it can be seen that the mixtures 2 (E) to 5 (E) and 7 (E) have a significantly reduced rebound resilience and show the best results in the High Speed Tear Energy Test. The High Speed Tear Energy Test can be used as a measure of crack initiation at the ends of metallic reinforcements, eg, due to the rapid energy load applied to the sample. B. at the belt edge, can be seen. Higher crack energy in the High Speed Tear Energy Test is accompanied by slower crack initiation and slower crack growth. Also, the data on Graves tear propagation resistance at room temperature and 100 ° C are equal or even improved compared to the corresponding comparative blends, indicating reduced tire cracking.

It should also be noted that the pull-out force and the degree of coverage of the samples are hardly changed or impaired by the measure of reducing the rebound resilience. The pull-out forces are at a similar level between 400 and 440 N and all variants show a good coverage of more than 90%. The rubber-metal adhesion is therefore not affected.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN 53 512 [0005]
• DIN 53 512 [0008]
• J. Schnetger, Encyclopedia of Rubber Technology , 2nd Edition, Hüthig Buch Verlag, Heidelberg, 1991, pp. 42-48 [0021]
• DIN 53 505 [0027]
• DIN 53 512 [0027]
• DIN 53 504 [0027]
• DIN 53 504 [0027]
• DIN 53 504 [0027]
• DIN 53 504 [0027]
• ASTM 2229 / D1871 [0027]
• DIN EN 10 045 [0027]
• DIN 53515 [0027]

Claims (12)

Pneumatic vehicle tires, in particular commercial vehicle tires, with metallic reinforcing elements, which are embedded in a gumming mixture and possibly surrounded by other abpolsterden and / or covering mixtures, characterized in that the gum mixture and / or the other abpolsterden and / or covering mixtures according to a rebound resilience at room temperature DIN 53 512 of less than 35% or have. Pneumatic vehicle tire according to claim 1, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures has or have a rebound resilience at room temperature according to DIN 53 512 of less than 30%. Pneumatic vehicle tire according to claim 1 or 2, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures 5 to 30 phr of at least one styrene-butadiene copolymer having a glass transition temperature T _g of more than -55 ° C, preferably more as -45 ° C, contains or contain. Pneumatic vehicle tire according to at least Claim 4, characterized in that the styrene-butadiene copolymer is an emulsion-polymerized styrene-butadiene copolymer (ESBR). Pneumatic vehicle tire according to at least one of claims 1 to 4, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures 2 to 10 phr at least one adhesive resin having a melting point Mp. Of more than 90 ° C, preferably more than 100 ° C, or have. Pneumatic vehicle tire according to claim 5, characterized in that the adhesive resin is a terpene-phenolic resin. Pneumatic vehicle tire according to at least one of claims 1 to 6, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures contains more than 60 phr, preferably more than 70 phr, natural rubber or contain. Pneumatic vehicle tire according to at least one of claims 1 to 7, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures contains more than 6 phr, preferably more than 7 phr, silica. Pneumatic vehicle tire according to at least one of claims 1 to 8, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures contain or contain an organic cobalt salt. Pneumatic vehicle tire according to at least one of claims 1 to 9, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures contains or contain at least 5 phr zinc oxide. Pneumatic vehicle tire according to at least one of claims 1 to 10, characterized in that the gumming mixture and / or the other abpolsterden and / or covering mixtures contain or contain a resorcinol-formaldehyde adhesive system. Pneumatic vehicle tire according to at least one of claims 1 to 11, characterized in that the gumming mixture for gumming of the belt and / or the carcass and / or the bead cores is used.