CA2305702C

Elastomer composite blends and methods for producing them

Abstract

Elastomer composite blends are produced by novel wet/dry mixing methods and apparatus. In the wet mixing step or stage, fluid streams of particulate filler and elastomer latex are fed to the mixing zone of a coagulum reactor to form a mixture in semi-confined flow continuously from the mixing zone through a coagulum zone to a discharge end of the reactor. The particulate filler fluid is fed under high pressure to the mixing zone, such as to form a jet stream to entrain elastomer latex fluid sufficiently energetically to substantially completely coagulate the elastomer with the particulate filler prior to the discharge end. Highly efficient and effective elastomer coagulation is achieved without the need for a coagulation step involving exposure to acid or salt solution or the like. Elastomer composites are produced. Such elastomer composites may be cured or uncured, and combine material properties, such as choice of filler, elastomer, level of filler loading, and macro-dispersion, not previously achieved. The coagulum produced by such wet mixing step, with or without intermediate processing steps, is then mixed with additional elastomer in a dry mixing step or stage to form elastomer composite blends. The additional elastomer to the coagulum may be the same as or different from the elastomer(s) used in the wet mixing step.

CA2305702C, drawing sheet 1
Sheet 1 of 44

Term

Term ended

Expired 28 September 2018, 8 years ago.

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30 claims: 10 independent, 20 dependent

  1. 1
    CA 02305702 2000-03-29 WO 99/16600 PCT/US98/20279 We claim:1. A method for producing elastomer composite blend comprising elastomer, particulate filler and optionally other ingredients, characterized by: feeding a continuous flow of first fluid comprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate filler under pressure to the mixing zone of the coagulum reactor to form a mixture with the elastomer latex, the particulate filler being effective to coagulate the elastomer latex and the mixing of the first fluid and the second fluid within the mixing zone being sufficiently energetic to substantially completely coagulate the elastomer latex with the particulate filler in the coagulum reactor;discharging a substantially continuous flow of elastomer composite from the coagulum reactor;and dry mixing the elastomer composite with additional elastomer to form elastomer composite blend.
  2. 2
    The method of producing elastomer composite blend in accordance with claim 1 further characterized in that:the elastomer latex and the additional elastomer each is independently selected from natural rubber, chlorinated natural rubber, homopolymer, copolymer terpolymers of 1,3-butadiene, styrene, isoprene, isobutylene, 2,3-dimethyl-l,3-butadiene, acrylonitrile, ethylene, and propylene, the oil extended derivatives of any of them, and mixtures of any of them;and the particulate filler is selected from carbon black, fumed silica, precipitated silica, coated carbon blacks, chemically functionalized carbon blacks, silicon-treated carbon black, and mixtures of any of them. Blends-CIP 149 SUBSTITUTE SHEET (RULE 26) CA 02305702 2006-12-21
  3. 3
    The method of producing elastomer composite blend in accordance with claims 1 or 2, further characterized in that additional particulate filler is added during the dry mixing of the elastomer composite with additional elastomer.
  4. 4
    The method of producing elastomer composite blend in accordance with claim 3, further characterized in that the additional particulate filler is mixed with the additional elastomer prior to the dry mixing of the elastomer composite with additional elastomer.
  5. 5
    The method of producing elastomer composite blend in accordance with any one of claims 1 to 4, further characterized by feeding additive to the mixing zone of the coagulum reactor, selected from antiozonants, antioxidants, plasticizers, processing aids, resins, flame retardants, extender oils, lubricants, and mixtures of any of them.
  6. 6
    The method of producing elastomer composite blend in accordance with any one of claims 1 to 5, further characterized in that:the elastomer latex and the additional elastomer is each independently selected from natural rubber latex, SBR rubber latex and butadiene rubber latex;the additional elastomer is present in an amount equal to 50% to 90% by weight of total elastomer in the elastomer composite blend;and the elastomer composite blend has 30 to 85 phr carbon black.
  7. 7
    The method of producing elastomer composite blend in accordance with any one of claims 1 to 5, further characterized in that the coagulum reactor defines an elongate coagulum zone extending with progressively increasing crosssectional area from the mixing zone to a discharge end.
  8. 8
    Elastomer composite blend comprising particulate filler finely dispersed in elastomer, characterized in that the elastomer composite blend is formed by a method comprising the steps of:feeding a continuous flow of first fluid comprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate filler under pressure to the mixing zone of the coagulum reactor to form a mixture with 150 CA 02305702 2006-11-28 the elastomer latex, the mixing of the first fluid and the second fluid within the mixing zone being sufficiently energetic to substantially completely coagulate the elastomer latex in the coagulum reactor;discharging a substantially continuous flow of elastomer composite from the coagulum reactor;and dry mixing the elastomer composite with additional elastomer to form elastomer composite blend.
  9. 10
    Vulcanizate comprising elastomer composite blend in accordance with claim 8 or 9, characterized by having a crack growth rate no more than 1.20 cm/million cycles, measured in accordance with ASTM D3629-94.
  10. 11
    An elastomer composite blend comprising at least 30 phr particulate filler dispersed in a multi-phase elastomer, the particulate filler being selected from carbon black, silicon coated carbon black, silicon treated carbon black, fumed silica, precipitated silica or a mixture of any of them, and each phase of the multiphase elastomer being independently selected from natural rubber, a chlorinated derivative of natural rubber, homopolymer, copolymer or terpolymer of butadiene, styrene, isoprene, isobutylene, 3,3-dialkyl-1,3-butadiene where the alkyl group is Cl to C3 alkyl, acrylonitrile, ethylene and propyline, an oil extend derivative of any of them and a mixture of any of them wherein macro-dispersion D(%) of the particulate filler in the elastomer composite blend is less than 0.2% undispersed area.
  11. 12
    Elastomer composite blend formed by:feeding a continuous flow of first fluid comprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate filler under pressure to the mixing zone of the coagulum reactor to form a mixture with the elastomer latex, the particulate filler being effective to coagulate the 151 CA 02305702 2006-11-28 elastomer latex and the feeding of the first fluid and the second fluid within the mixing zone being sufficiently energetic to substantially completely coagulate the elastomer latex with the particulate filler in the coagulum reactor;discharging a substantially continuous flow of elastomer composite from the coagulum reactor;and dry mixing the elastomer composite with additional elastomer to form the elastomer composite blend, wherein the additional elastomer comprises additional particulate filler.
  12. 26
    Elastomer composite blend formed by:feeding a continuous flow of first fluid comprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate filler under pressure to the mixing zone of the coagulum reactor to form a mixture with the elastomer latex, the particulate filler being effective to coagulate the elastomer latex and the feeding of the first fluid and the second fluid within the mixing zone being sufficiently energetic to substantially completely coagulate the elastomer latex with the particulate filler in the coagulum reactor;discharging a substantially continuous flow of elastomer composite from the coagulum reactor;and dry mixing the elastomer composite with additional elastomer to form the elastomer composite blend, wherein the additional elastomer is polybutadiene.
  13. 27
    Elastomer composite blend formed by:153 CA 02305702 2006-11-28 feeding a continuous flow of first fluid comprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate filler under pressure to the mixing zone of the coagulum reactor to form a mixture with the elastomer latex, the particulate filler being effective to coagulate the elastomer latex and the feeding of the first fluid and the second fluid within the mixing zone being sufficiently energetic to substantially completely coagulate the elastomer latex with the particulate filler in the coagulum reactor;discharging a substantially continuous flow of elastomer composite from the coagulum reactor;and dry mixing the elastomer composite with additional elastomer to form the elastomer composite blend, wherein the additional elastomer is polypropylene.
  14. 28
    A method of producing elastomer composite blend, comprising:feeding a continuous flow of first fluid comprising elastomer latex to a mixing zone of a coagulum reactor;feeding a continuous flow of second fluid comprising particulate filler under pressure to the mixing zone to form a mixture with the elastomer latex, the feeding of the second fluid against the first fluid within the mixing zone being sufficiently energetic to substantially completely coagulate the elastomer latex with the particulate filler;discharging a substantially continuous flow of elastomer composite from the coagulum reactor;and mixing the elastomer composite with additional elastomer to form the elastomer composite blend.
  15. 29
    The method of producing elastomer composite blend in accordance with claim 28, wherein the additional elastomer is dry mixed with the elastomer composite to form the elastomer composite blend.
  16. 30
    The method of producing elastomer composite blend in accordance with claim 28, wherein the second fluid is an aqueous fluid having 10 to 30 wt. % carbon black. 154
Independent claims16