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EP-4347704-B1 - RUBBER COMPOSITION CONTAINING ADDITIVE AND ITS USE

EP4347704B1EP 4347704 B1EP4347704 B1EP 4347704B1EP-4347704-B1

Inventors

  • BÖRGER, Volker
  • GEIDEL, CHRISTIAN

Dates

Publication Date
20260513
Application Date
20220603

Claims (15)

  1. Rubber composition which contains rubber and at least one rubber additive, characterized in that the at least one rubber additive comprises rosin ester from rosin and at least one alcohol, wherein the rosin used to prepare the rosin ester has an acid number of from 130 to 190 mg KOH/g and the alcohol(s) used has or have not more than seven hydroxyl groups and a molecular weight of at least 200 g/mol.
  2. The rubber composition according to claim 1, characterized in that the at least one alcohol used to prepare the rosin ester has a molecular weight of at least 380, preferably from 380 to 2000 g/mol, and/or that the at least one alcohol used to prepare the rosin ester has 2, 3 or 4 hydroxyl groups.
  3. The rubber composition according to any one of the preceding claims, characterized in that the at least one alcohol used to prepare the rosin ester is selected from the group consisting of C 2 to C 4 alkoxylate of a polyol, polyethylene glycol, polypropylene glycol and/or copolymer of ethylene oxide and propylene oxide, wherein the at least one alcohol used to prepare the rosin ester is preferably selected from the group consisting of polyethylene glycol (PEG), such as PEG having a molecular weight of from 200 to 800 g/mol, polypropylene glycol (PPG), such as PPG having a molecular weight of from 200 to 800 g/mol and ethoxylated glycerol that has in particular up to 10, such as 5 to 10, e.g. 7, ethylene oxide units (EO units).
  4. The rubber composition according to any one of the preceding claims, wherein the rosin used to prepare the rosin ester has an acid number of from 140 to 180 mg KOH/g.
  5. The rubber composition according to any one of the preceding claims, characterized in that the composition contains between 0.1 and 40 phr rosin ester, preferably 1 to 30 phr, and/or that the rosin used to prepare the rosin ester is a disproportionated rosin.
  6. The rubber composition according to any one of the preceding claims, characterized in that it comprises at least one styrene-butadiene rubber, polyisoprene rubber, natural rubber and/or butadiene rubber as well as optionally the functionalized forms thereof.
  7. The rubber composition according to any one of the preceding claims, characterized in that the composition has an at least 5%, preferably 10%, lower rolling resistance, tan delta at 60 °C., and/or a 5%, preferably 10%, higher wet grip, tan delta at 0° C., after vulcanization in comparison with an identical composition which comprises a known rubber additive in identical quantity instead.
  8. The rubber composition according to any one of the preceding claims, characterized in that the composition is suitable for the preparation of tread compounds for tyres.
  9. The rubber composition according to any one of the preceding claims, characterized in that the composition contains further additives and constituents which are suitable for the preparation of tread compounds for tyres, in particular one or more fillers and optionally further additions.
  10. The use of rosin ester from rosin and at least one alcohol as rubber additive in a rubber composition for improving the Mooney viscosity of the rubber composition and/or for improving at least one of wear, grip and rolling resistance of a tyre produced from the rubber composition, wherein the rosin used has an acid number of from 130 to 190 mg KOH/g and the alcohol(s) used has or have a molecular weight of at least 200 g/mol and at least two hydroxyl groups and not more than seven hydroxyl groups.
  11. The use of claim 10, wherein at least one of the named properties is improved by at least 5%, preferably at least 10%, compared with a rubber composition which comprises a known rubber additive in identical quantity instead.
  12. The use of claim 10 or claim 11, characterized in that the rosin ester is as defined in any one of claims 1 to 4 and/or that the rosin ester is as defined in any one of claims 5 to 9.
  13. The use of any one of claims 10 to 12 characterized in that a blend is used which contains a) one or more solid carrier material(s), wherein a silica is preferably used as carrier material, b) one or more of the rosin esters.
  14. Process for producing a tyre, characterized in that one or more component parts of the tyre are produced from a rubber composition according to any one of claims 1 to 9 and the rubber composition is cured.
  15. A tyre in which at least one component part has been produced at least partially from a rubber composition according to any one of claims 1 to 9, and the tyre is preferably an Ultra High Performance (UHP) or summer tyre, wherein the component part is in particular the tyre tread.

Description

Field of invention The present invention relates to a rubber composition comprising rubber and at least one rubber additive based on a higher molecular weight rosin resin ester. The present invention further relates to the use of the rubber additive in a rubber composition, a tire in which at least one component is at least partially made from the rubber composition according to the invention, and methods for its production. Background of the invention Vehicle tires must meet various requirements in road traffic. Typically, the tread compound is optimized for the specific demands of a tire in its respective area of application. In recent years, the development of tread compounds for ultra-high-performance (UHP) and summer tires has focused on improving properties such as tire grip, wear resistance, and handling. For this purpose, a high resin content, e.g., based on alpha-methylstyrene, terpene, and coumarin resins, has been added to the rubber compounds used in the manufacture of passenger car tires. However, the above approach results in poorer processability of the rubber compound, particularly stickiness, high viscosity, and insufficient green strength. To eliminate or reduce these problems, the rubber industry uses a variety of processing aids (additives), but their application often leads to disadvantages in other desired properties, such as lower stiffness of the rubber or the rubber compound produced from it for the tire. This results in increased tire wear and poorer performance. Tire handling. Poor tire wear characteristics are problematic due to the material released (fine dust issue). A tire's wet grip plays a significant role in safety, and its rolling resistance affects energy consumption. It is well known in the industry that improving one physical property of a rubber compound comes at the expense of another. A so-called trade-off exists in tread compounds between the processability of the rubber composition on the one hand and at least one of the properties related to wet braking performance, rolling resistance, and tire wear on the other. Such a compromise between good processing properties and disadvantages in performance criteria such as tire grip (wet and dry grip, tire wear, and tire handling) is becoming increasingly unacceptable. The WO 2016/105909 A1 This concerns rubber compositions comprising rubber, silica, organosilane containing at least one cyclic and/or bridged alkoxy group, and "rosin-containing material." The described rubber compositions can be used for the manufacture of tires. The rubber compositions may include rosin esters. WO '909 does not disclose the use of high molecular weight rosin esters. The WO 2017/117578 A1 This relates to a process for producing a molded rubber composition, wherein a rubber compound is combined with an extender compound. The described rubber compositions can be used for the manufacture of tires. The extender compound can be a rosin resin ester, wherein, among others, ethylene glycol, diethylene glycol, or triethylene glycol can be used as the alcohol. The WO 2011/130525 A1 concerns a tire rubber composition comprising a rubber compound and a process oil, The process oil in turn comprises a modified tall oil pitch, and tires manufactured from it (see summary). Tall oil (also known as liquid rosin) is an oily mixture obtained as a byproduct of pulp production. Tall oil pitch typically contains 2–8 wt% fatty acids, 3–15 wt% resin acids, and 30–45 wt% unsaponifiable material. The acid value of tall oil pitch ranges from 15 to 50. One object of the present invention is the development of a new additive for ultra-high-performance (UHP) and summer tires that improves the processing properties of the rubber compound used to manufacture these tires. At the same time, the other performance characteristics of the tires, in particular handling, wet and dry braking performance, tire wear, and rolling resistance, should not be impaired or should even be at least partially improved. Summary of the invention The object of the invention is achieved by a rubber composition containing rubber and at least one rubber additive, characterized in that the at least one rubber additive comprises rosin resin esters made from rosin resin and at least one alcohol, wherein the rosin resin used to produce the rosin resin ester has an acid number of 130 to 190 mg KOH/g and the alcohol(s) used has at least 2 hydroxyl groups and not more than seven hydroxyl groups and a molecular weight of at least 200 g/mol. Another aspect of the present invention relates to the use of rosin resin esters from rosin resin and at least one alcohol as a rubber additive in a rubber composition to improve the Mooney viscosity of the rubber composition and/or to improve at least one of the abrasion, adhesion and rolling resistance properties of a rubber compound. a tire made from the rubber composition, wherein the rosin resin used has an acid number of 130 to 190 mg KOH/g and the alcohol(s) u