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EP-4558558-B1 - A RUBBER COMPOUND MIXTURE

EP4558558B1EP 4558558 B1EP4558558 B1EP 4558558B1EP-4558558-B1

Inventors

  • TWIGG, CHRISTOPHER MICHAEL
  • JONKMAN, Jan Anne
  • DAMSTER, Justin Michael

Dates

Publication Date
20260513
Application Date
20230711

Claims (15)

  1. A rubber compound mixture comprising a matrix of a non-vulcanized rubber including micronized rubber powders having a particle size which is within the range of 420 microns or smaller and one or more auxiliaries, wherein the surface of the micronized rubber powders is functionalized with a silica component, a silane component and one or more functionalization components.
  2. A rubber compound according to claim 1, wherein the one or more functionalization components are chosen from the group of diphenyl guanidine, hexylamine, decylamine, octadecylamine, cyclohexylamine, dicyclohexylamine, quinuclidine, di-o-tolylguanidine, dithiophosphate, phosphoryl polysulphide, and diazabicycloundecene.
  3. A rubber compound according to claim 1, wherein the functionalization component is diphenyl guanidine.
  4. A rubber compound according to any one or more the preceding claims, wherein the amount of the one or more functionalization components is at least 0,1 wt.% and at most 1 wt.%, based on the total weight of the rubber compound mixture.
  5. A rubber compound according to any one or more the preceding claims, wherein the silica component is chosen from the group of synthetic amorphous precipitated silicas having a BET surface area of at least 165 m 2 /g, especially wherein the amount of the silica component is at least 7 wt.%, preferably at least 15 wt.% and at most 36 wt.%, preferably at most 25 wt.%, based on the total weight of the rubber compound mixture, measured in accordance with ISO 9277 (multipoint).
  6. A rubber compound according to any one or more the preceding claims, wherein the silane component is chosen from the group of polysulphide organosilanes, especially wherein the amount of the silane component is at least 0,5 wt.%, preferably at least 1 wt.% and at most 4 wt.%, preferably at most 3 wt.%, based on the total weight of the rubber compound mixture.
  7. A rubber compound according to any one or more the preceding claims, wherein the non-vulcanized rubber is natural rubber.
  8. A rubber compound according to any one or more the preceding claims, wherein the amount of micronized rubber powders is at least 1 wt.% and at most 50 wt.%, based on the total weight of the rubber compound mixture.
  9. A rubber compound according to any one or more the preceding claims, wherein the particle size distribution (PSD) of the micronized rubber powder (MRP) is such that D95 < 200 µm and D50 < 120 µm, preferably D95 < 180 µm and D50 < 100 µm.
  10. A method for preparing a rubber compound mixture comprising a matrix of non-vulcanized rubber including micronized rubber powders and one or more auxiliaries, the method comprising the following: a) providing a micronized rubber powder having a particle size which is within the range of 420 microns or smaller, b) providing a non-vulcanized rubber, c) mixing the micronized rubber powder of step a) and the one or more functionalization components under high speed in a mixing unit, d) adding the silica component and silane component to the mixture of step c) under high speed, e) removing the functionalized micronized rubber powder from the mixing unit, f) mixing the functionalized micronized rubber powder of step e) with the non-vulcanized rubber of step b) and the one or more auxiliaries for obtaining the rubber compound mixture.
  11. A method according to claim 10, wherein in step d) the silane component is added after the silica component and the one or more functionalization components.
  12. A method according to any one of claims 10-11, wherein the one or more auxiliaries are chosen from the group of peptizer, carbon black, recovered carbon black, silica, stearic acid, scorch retarder, antidegradants, plasticizer, sulphur, accelerators, organic peroxides, peroxide-cure coagents and processing aids.
  13. A method according to any one of claims 10-12, wherein in step f) the non-vulcanized rubber of step b) and the one or more auxiliaries are pre-mixed and the premix thus obtained is mixed with the functionalized micronized rubber powder of step e) for obtaining the rubber compound mixture.
  14. A method for manufacturing a rubber article via vulcanization, wherein the rubber compound mixture according to any one or more of the claims 1-9 or a rubber compound mixture obtained according to a method according to claims 10-13 is vulcanized under elevated pressure and temperature.
  15. Rubber article, comprising a matrix of vulcanized rubber matrix including functionalized micronized rubber powders, obtained according to a method for manufacturing a rubber article via vulcanization according to claim 14.

Description

The present invention relates to a rubber compound mixture comprising a matrix of a non-vulcanized rubber including micronized rubber powders and one or more auxiliaries. The present invention also relates a method for preparing such a rubber compound mixture, as well as to a rubber article. Micronized rubber powder (MRP) is a low-cost, sustainable raw material that replaces crude oil-derived and natural rubber-based materials. MRP is a free flowing, black rubber powder that disperses into a multitude of systems and applications. Due to its micron size, MRP can be incorporated into multiple polymers, and provides a smooth surface appearance on finished products. In some cases, in order to improve compatibility and performance with host materials, the MRP is given a chemical treatment to activate, or "make functional" the surface of the powder particles. This is referred to as functionalized MRP or FMRP. Non-functionalized MRP only finds applications as a cheap filler. Micronized rubber powders (MRP) typically contain a significant fraction of rubber particles having a particle size of less than 100 microns. Powders having a particle size which is within the range of 40mesh (420 microns) or smaller are considered to be micronized rubber powder. MRP represents an evolution over previous post-manufactured rubber technologies. The most basic rubber processing technology converts end-of-life tyre and post-industrial rubber material into rubber chips that are typically 10 to 50cm or larger in size. These chips are then used in tyre-derived fuel and civil engineering projects. MRP is a micron-size material that is produced in many sizes, including 80 mesh (177 microns) and down to 325 mesh (44 microns). Only FMRP finds its way into high end applications, such as high-performance tyres, industrial rubber, consumer and industrial plastics goods, asphalt and coatings and construction materials. MRP is used as a compound extender to offset the use of natural rubber, synthetic polymers and furnace carbon black as well as function as a process aid in material production. Rubber formulations comprising micronized rubber powder are known in the art. International application WO 2021/167457 in the name of the present inventors relates to a method for manufacturing micronized rubber powders comprising grinding of a rubber granulated feedstock, size classification and storage of the micronized rubber powders thus obtained, wherein during the grinding process an agent is used to prevent the rubber powder particles sticking to themselves. US 2016/297243 relates to a tyre which is comprised of a toroidal-shaped carcass with an outer circumferential tread, two spaced beads, at least one ply extending from bead to bead and sidewalls extending radially from and connecting said tread to said beads, wherein the sidewalls comprise micronized rubber powder. US 2016/152805 relates to a rubber composition which is comprised of a solution styrene-butadiene rubber; a functionalized renewed rubber composition which is comprised of an elastomeric polymer and a stabilizer, and a reinforcing filler including reinforcing silica. EP 3 045 492 relates to a rubber formulation which is useful in rubber products or components of rubber products which are subject to abrasive forces, said rubber formulation comprises at least one natural or synthetic rubber and from 1 weight percent to 30 weight percent of a micronized rubber composition having a particle size which is within the range of 40 mesh (420 microns) to 200 mesh (74 microns), wherein the micronized rubber composition is comprised of at least 10 weight percent solution styrene-butadiene rubber. US 2014/128535 relates to a method of functionalizing reclaimed elastomer material, the method comprising subjecting particles of the reclaimed elastomer material to shear at temperatures less than 100° C. such that inter-chain bonds of the reclaimed elastomer material are cleaved. US 2017/114155 relates to a method for manufacturing a chemically functionalized, renewed rubber composition comprising the steps of blending a micronized rubber powder, i.e. a styrene-butadiene rubber, with a processing aid and a functionalizing agent to produce a blended mixture, processing the blended mixture under conditions of high shear and low temperature to produce a reacted mixture, and adding a stabilizer, i.e. N-cyclohexyl(thio)phthalimide, to the reacted mixture to produce the renewed rubber. The processing under conditions of high shear is generated on a 2-roll mill, wherein the functionalizing agent is a compound selected from the group consisting of alkyl thiuram sulfides, aryl thiuram sulfides, heterocyclic thiuram sulfides, thiuram disulfides, thiuram polysulfides, thiuram disulfides, thiuram multisulfides, tetrabenzylthiuram disulfides, cyclohexyl sulfonamides, t-butyl sulfonamides, tetraalkylthiuram disulfides, tetramethylthiuram disulfides, tetraethylthiuram disulfides, dipentamethylthiuram monosulfides,