• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method of drying a natural rubber from a moist natural rubber coagulum which is in a first step compressed at a temperature of from 190 ° C to 210 ° C, and then in a second step undergoes a adiabatic flash trigger at a differential pressure of at least 100 bar. Possibly supplemented with convective drying or reiteration of the first and second stages, the process results in a dry natural rubber with a nitrogen content of not more than 0.3%.
    公开号:FR3051795A1
    申请号:FR1654878
    申请日:2016-05-31
    公开日:2017-12-01
    发明作者:Jerome Dussillols；Jean-Luc Merceron；Sébastien Geffroy；Alexandre MARCHI
    申请人:Michelin Recherche et Technique SA Switzerland ；Compagnie Generale des Etablissements Michelin SCA；Michelin Recherche et Technique SA France；
    IPC主号:
    专利说明:

    The invention relates to a method for drying natural rubber from a natural rubber coagulum.
    Natural rubber which contains a high cis content polyisoprene matrix is an elastomer very widely used in the tire field because of its remarkable properties. For example, it is used in rubber compositions for the manufacture of semi-finished for vehicles carrying heavy loads, because of the compromise of performance that it can bring to the tire. Indeed, the introduction of natural rubber in a rubber composition reinforced by a reinforcing filler such as a carbon black gives the rubber composition a compromise that is quite interesting in terms of hysteresis and wear, which translates into of performance for the tire by a good compromise between endurance and tire wear.
    Natural rubber comes from the rubbery dry matter of the natural rubber latex, which is often extracted from the rubber tree after bleeding: the latex is generally collected in a cup called a cup. According to a first so-called spontaneous coagulation method, the latex coagulates directly in the cup to form a coagulum known as "cup lump", a term that is well known to those skilled in the rubber manufacturing field. natural. According to a second so-called coagulation method, the still-liquid latex in the cup is decanted, optionally stabilized or centrifuged, and then coagulated for example with the aid of a chemical agent.
    The spontaneous or induced coagulation product of the natural rubber latex, hereinafter referred to as the coagulation product, comprises the polyisoprene matrix soaked with a serum. The product of coagulation can be washed to remove contaminants such as leaves, twigs, sand and other debris, but also it can be shredded in the form of granules (in English "crumbs"), washed with water in pools, possibly drained, and finally dried to remove water. There are several drying processes used to remove water from natural rubber, widely known and practiced by those skilled in the field of the manufacture of natural rubber, in particular for the manufacture of grades TSR3, TSR5, TSRIO, TSR20 or RSS. According to the processes traditionally used on natural rubber manufacturing sites, the coagulation product is dried at a moderate temperature of the order of 40 to 60 ° C for 4 to 6 days, for example in the open air or in the air. smokehouses, or at a higher temperature, typically 90 to 130 ° C, for a much shorter time in tunnels under air circulation.
    These drying steps traditionally used have the drawback of having long drying times or of degrading the macrostructure of the polyisoprene chains of natural rubber, or of reducing the resistance of natural rubber to oxidative aging.
    To solve the problems mentioned above, it has been described to dry natural rubber otherwise than by conventional methods. For example, JP 2010-260930 teaches drying of the coagulation product in an extruder by squeezing at 130 ° C and then on a vibrating screen at a temperature of at most 130 ° C. US 20130032045 discloses a process which comprises squeezing the coagulation product in an extruder and then removing residual water at temperatures of 140 to 180 ° C and pressures of 15 to 20 MPa in a process structure. elongated tunnel having a screw.
    Moreover, it is known that the natural rubber latex contains nitrogen compounds such as proteins. The presence of these nitrogen compounds in natural rubber whose content in natural rubber is measured by the nitrogen content in natural rubber, can be at the origin of allergies observed in contact with manufactured products from natural rubber, such as gloves. As the content of nitrogen compounds in natural rubber is correlated with the level of nitrogen in natural rubber, it is therefore a constant concern to reduce the nitrogen content in natural rubber. It is known to reduce the level of nitrogen by chemical treatments carried out on the natural rubber latex or on the coagulation product, in particular by saponification reaction or by enzymatic reaction, as described for example in EP 584 597 and WO 2005590412. The disadvantage of these technologies is to introduce at least one additional step in addition to the washing and drying steps in the natural rubber manufacturing process.
    It is therefore of interest to find a method which makes it possible to solve all the mentioned problems which are related to the removal of water and nitrogen compounds from natural rubber while preserving the properties of natural rubber.
    The Applicants have surprisingly discovered that the application of a trigger to a coagulum of natural rubber under conditions of specific temperature and pressure supplemented optionally by a convective drying or one or more new detents allows both eliminate water and reduce the nitrogen content in natural rubber. Typically at the end of the process according to the invention, the water content in the natural rubber is less than 0.8% and the nitrogen content is at most 0.3%, preferably ranging from 0.2% to 0.3%. Preferred embodiments of the invention make it possible to achieve such a low residual water content and an even lower nitrogen content, namely a residual water content of less than 0.8% and a nitrogen content of less than 0%. 3%, especially between 0.2% and 0.3%. Furthermore, the Applicants have discovered that the natural rubber resulting from preferred variants of the process according to the invention has a better resistance to aging by oxidation as well as a high weight average molecular weight.
    Thus, a first object of the invention is a method of drying a natural rubber which comprises the following steps: a) having a coagulum of wet natural rubber, b) compressing the coagulum at a temperature ranging from 190 ° C. at 210 ° C, c) subjecting the compressed coagulum to an adiabatic flash trigger at a differential pressure of at least 100 bar, d) optionally subjecting the coagulum resulting from step c) to convective drying or to one or several iterations of the sequence of steps b) and c).
    Another subject of the invention relates to a natural rubber which can be obtained by preferred embodiments of the process according to the invention and which has the particularity of having both a weight average molecular weight greater than 1000 000, a nitrogen level of less than 0.3% and a plasticity retention index greater than 100. DETAILED DESCRIPTION OF THE INVENTION
    Any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (i.e., terminals a and b excluded) while any range of values designated by the expression "from a to b" means the range from a to b (i.e., including the strict limits a and b). Unless expressly indicated otherwise, all the percentages (%) indicated are% by mass.
    In the present application, the term "natural rubber latex" means the latex resulting from the bleeding rubber tree.
    In the present application, the term "extruder" is understood to mean a worm-screw machine which comprises an inlet of material called a hopper, a body formed of a cylinder (also called a sleeve) in which a screw (one or more) endlessly turns and a head that serves as a support for a die. This machine makes it possible to apply mechanical drying or thermomechanical drying. Mechanical drying allows the elimination of liquid by purely mechanical forces (pressing, spinning, ...). It can be achieved by simple transfer of momentum and optionally without heat transfer. The thermomechanical drying is carried out by heating to the product to be dried by degradation of the mechanical energy. The water included in the product to be dried is in the liquid state under high pressure and at high temperature. At the outlet of the die, the trigger produced makes it possible to flash the moisture and, if appropriate, depending on the viscosity of the product, to fragment the product.
    The process according to the invention is suitable for drying a coagulum whose water content in step a) is 3 to 5%. It is also suitable for drying a coagulum whose water content in step a) is greater than 5%. It is also very suitable for drying a coagulum whose water content in step a) is greater than 12%.
    The process according to the invention makes it possible to obtain a dry natural rubber, that is to say a natural rubber whose water content is less than 0.8%. The process also produces not only dry natural rubber, but also natural rubber in which the nitrogen content is reduced. The process according to the invention makes it possible to reduce the nitrogen content in the natural rubber by at least 20% or more, since the reduction in the nitrogen content can be up to 40%. The extent of the decrease is a function of the level of nitrogen present in the natural rubber used in step a). The higher the level of nitrogen in the natural rubber used in step a), the higher the decrease in the nitrogen content in the natural rubber dried by the process according to the invention.
    Indeed, the nitrogen content in the natural rubber used in step a) may vary from one natural rubber to another. It may depend on the geographical area of the rubber crop, the plant variety of the rubber tree, the season on which the bloodletting was carried out, the maturation time which generally corresponds to the lapse of time between bleeding. and the machining (in English "remilling") of natural rubber. It is recalled that machining is the well known name and used to describe all the processing operations which comprises the steps of grinding, washing, drying.
    The nitrogen content of the natural rubber used in step a) may therefore vary from 0.25% to more than 0.3%, the low value may correspond to the most important maturation times. The level of nitrogen in the natural rubber used in step a) is preferably greater than 0.3%, especially greater than or substantially equal to 0.4%. Thus, the process according to the invention makes it possible to obtain a dry natural rubber whose nitrogen content is at most 0.3%, preferably ranging from 0.2% to 0.3%, more preferably between 0.2%. and 0.3%.
    The coagulum used in step a) (or in other words it is arranged in step a)) is a product of the coagulation of the natural rubber latex, indifferently obtained by spontaneous or induced coagulation. Preferably, the coagulum is a cup bottom.
    The coagulum is said to be wet because it is soaked with water which comes in particular from washing water resulting from coagulum washing operations generally conducted in the pool under water. The coagulum used in step a) is preferably a coagulum which has been washed and generally contains more than 12% by weight of water. The water content in the coagulum used in step a) is more preferably from 17 to 25%, such water contents being those generally determined in the coagulums after the washing operations in the natural rubber remilling plants. .
    Preferably, the coagulum used in step a) is in the form of granules (in English "crumbs"). More preferably, the coagulum used in step a) is in the form of granules previously washed with water and therefore loaded with water, especially in the contents indicated above, in particular greater than 12%. Step b) of the process according to the invention is a compression of the coagulum. This compression is necessary so that the coagulum can subsequently be subjected to adiabatic relaxation. The pressure at which the coagulum is compressed must be sufficient to allow adiabatic expansion at a differential pressure of at least 100 bar. The coagulum is compressed at a pressure preferably of at least 100 bar, more preferably at least 120 bar, more preferably at least 150 bar.
    Compression can be achieved by any known means to pressurize a rubbery material soaked in water. As suitable means, there may be mentioned presses such as those consisting of jaws or plates that sandwich the coagulum, worm machines equipped with a die at the end of the screw. To achieve the pressures useful for the purposes of the invention at the end of the screw in a worm machine, the skilled person can play for example on the coagulum flow in the worm machine, the speed of the screw, on its geometry, on the shape of the holes of the die, on their number or on their diameter. An extruder equipped at the end of a die with several holes is particularly preferred. At the pressure useful to the needs of the invention to achieve compression, the coagulum is heated to a temperature ranging from 190 to 210 ° C. In a worm machine such as an extruder, the mechanical work under high pressure is accompanied by a heating of the rubbery material of the coagulum, which has the effect of increasing the temperature of the coagulum. The temperature must not exceed 210 ° C in order not to degrade the polyisoprene chains. Below 190 ° C, the amount of heat supplied to the coagulum is insufficient to cause both the vaporization of water and the removal of some of the nitrogen compounds of the natural rubber during relaxation. To achieve the temperatures useful for the purposes of the invention, calories can also be provided by heating the means used to perform the compression, for example by heating the jaws or plates of a press machine or the inside of a machine screw such as the sheath of an extruder via a double jacket.
    The time during which the coagulum is subjected to compression at the temperature and pressure useful for the needs of the invention is relatively short not to degrade the polyisoprene chains, but sufficient to provide the amount of heat sufficient to cause the vaporization of water and the elimination of a part of the nitrogen compounds during the relaxation.
    The adiabatic expansion performed in step c) is characterized by flash trigger in that it allows the coagulum to go from a compressed state to an uncompressed state almost immediately, typically in a time less than one second. It is carried out at a differential pressure of at least 100 bar, which makes it possible to vaporize the water and to eliminate a part of the nitrogenous compounds by a flash effect. The higher the differential pressure, the more effective the flash is in reducing the amount of water and nitrogen in the natural rubber. Preferably, the differential pressure is at least 150 bar. Since the expansion is adiabatic, the expansion occurs at the temperature at which the compression was performed. At the end of relaxation, the coagulum is usually at atmospheric pressure. In the case where an extruder equipped with a screw end die is used to perform step b), flash adiabatic expansion in step c) occurs at the outlet of the die. A release of the stresses previously exerted on the coagulum in the sleeve takes place at the exit of the die by the suppression of the compression, which allows flash adiabatic expansion at the exit of the die. In the case where a press is used to compress the coagulum, the release of the stresses is caused by the rapid opening of the press.
    At the moment of expansion performed in step c), the greater the coagulum has a large external surface in contact with the atmosphere, the greater the exchange surface of the coagulum with the atmosphere, the more efficient the process is to reduce the amount of water and the amount of nitrogen in the natural rubber. Therefore, it is preferable that the coagulum has the largest possible area per volume unit in step c). For example, in the case of expansion at the die exit of an extruder, the coagulum is advantageously in a form divided in step c). Typically, the coagulum can be cut just before relaxation, by the establishment of means capable of cutting the coagulum out of the die such as a knife or a granulator, preferably a granulator. Such devices comprising a granulator at the end of a screw die of an extruder are well known for use in the manufacturing processes of synthetic rubbers. In the case where a press is used as a means to pressurize the wet coagulum, the exchange surface of the coagulum with the ambient atmosphere is renewed before each new cycle of compression and expansion, for example by folding the surface of the coagulum. on itself before compressing it again. This surface renewal also makes it possible to improve the efficiency of the process which uses a press.
    According to a first alternative, step d) consists in convectively drying the coagulum. Any known means for convection drying may be suitable. Particularly preferred is a fluidized bed such as a vibrating screen, a device known and conventionally used in synthetic rubber manufacturing processes. Convective drying is preferably carried out under air. The convective drying under air is preferably at a temperature of 110 ° C to 130 ° C. The convection drying time is adjusted by those skilled in the art as a function of the drying temperature in step d) and as a function of the residual water content in the coagulum at the end of step c). It is preferred to apply in step d) as short a drying time as possible to preserve the structure of polyisoprene chains of natural rubber and its properties. Typically the convection drying time is less than 10 minutes so as to obtain a natural rubber containing less than 0.8% water.
    According to a second alternative, step d) consists in subjecting the coagulum to a new compression followed by a new expansion under the conditions described in step b) and in step c) respectively. If necessary, it may be necessary to repeat this sequence of steps to achieve both a water content in the natural rubber of less than 0.8% and a reduction of the nitrogen content of at least 20% in the natural rubber.
    According to one embodiment, step d) is performed. The conduct of step d) is appropriate according to the residual water content obtained at the end of step c) of the process. The water content in the natural rubber at the end of step c) depends not only on the pressure and temperature conditions applied in steps b) and c), but also on the initial water value in the coagulum used. in step a). Those skilled in the art understand that the higher the coagulum of step a) is loaded with water, the higher the residual water content may be at the end of step c) and that it may then be necessary to proceed with additional drying, step d). For example, the treatment according to the method of two coagula charged with 3 to 5% water for the first and more than 12% water for the second leads at the end of step c) to a water content residual less than 0.8% for the first and 3 to 5% for the second. In the case of the second coagulum, step d) is necessary to reduce the water content to less than 0.8%.
    To complete the drying of a coagulum which results from step c), the person skilled in the art preferentially selects one alternative over the other, taking into account the residual water content and the nitrogen content in the natural rubber. . Convective drying can ensure only the removal of water, it is preferred to complete the drying of a coagulum resulting from step c) whose nitrogen content is at most 0.3% and whose content in water is in the range of 3 to 5%. This is typically the case when step c) is conducted in an extruder equipped at the end of a die screw and a tool for cutting the coagulum, such as a granulator.
    A divided form of the coagulum is preferred in step d), whether it is carried out according to the first or the second alternative. For the same reasons as those put forward in step c), it makes it possible to improve the efficiency of step d) in obtaining a residual water content of less than 0.8% in natural rubber, especially in reducing the duration of step d). The extruder useful for the purposes of the invention may be an extruder available on the market, in particular those marketed by the Anderson, FOM and Welding companies, such as, for example, the Anderson Expander, the FOM Extruder Dryer, the VCU. of Welding.
    Extruder variants are preferential in that they allow, at the outlet of the die, to reach higher flows of coagulum or to promote adiabatic expansion. Such a preferred variant is an extruder whose sheath has in the feed zone of the extruder one (one or more) means for discharging water (free water, in liquid form). As evacuation means, there may be mentioned grooves in the thickness of the sheath that open on the inner surface of the sheath, one or more openings in the feed zone of the extruder, opening which makes it possible to evacuate the water. out of the scabbard. These openings may be in the form of slot, grid, circular hole. The feeding area is the area under the opening of the hopper. The extruder useful for the purposes of the invention is preferably a single screw extruder.
    According to a particular embodiment, the method according to the invention has the advantage of being able to be implemented with a device comprising a single worm machine and a hot air fluidized bed, the worm machine being an extruder equipped at the end of a screw with a hole die and a means capable of cutting the coagulum and disposed after the die, which means is preferably a granulator.
    According to a variant of this particular embodiment, the sheath of the extruder has in the feed zone of the extruder one or more means for discharging water, for example those mentioned above.
    According to another variant of this particular embodiment, the extruder is a single screw extruder.
    According to another variant of this particular embodiment, the extruder comprises a double envelope.
    According to yet another variant of this particular embodiment, the hot air fluidized bed is a vibrating screen.
    According to this particular embodiment, including in its variants which can be combined, the process makes it possible to remove water and a part of the nitrogen compounds from a coagulum in the form of granules loaded with water at a content greater than 12. %. Indeed, it makes it possible to obtain a natural rubber having a water content of less than 0.8%, a nitrogen content of less than 0.3%, a weight average molar mass of greater than 1 000 000 g / mol and an index plasticity retention greater than 100.
    According to this particular embodiment, including in its variants described above, the method preferably comprises steps a), b), c) and d), the steps a), b) and c) being as defined according to any one of the embodiments of the invention, step d) being defined according to the alternative, including its preferred aspects, which uses convection drying.
    Natural rubber, another object of the invention, has the essential characteristic of having a weight average molecular weight greater than 1,000,000 g / mol, a water content of less than 0.8% and a nitrogen content of less than 0.3%. and a plasticity retention index (PRI) of greater than 100. The natural rubber which can be obtained according to preferred embodiments of the invention has much improved properties compared to natural rubber dried by conventional methods such as grade TSR20 natural rubber. Indeed, the natural rubber according to the invention has a very improved oxidation aging resistance due to the high value of the PRI. PRI is the percentage ratio of the plasticity of aged natural rubber to the plasticity of natural rubber before aging. Its determination according to ASTM D 3194-04 is used to give an indication of the resistance to oxidation of natural rubber. The higher the value, the better the resistance to aging by oxidation. Preferably, the natural rubber according to the invention has a nitrogen content of between 0.2 and 0.3%.
    The aforementioned features of the present invention, as well as others, will be better understood on reading the following description of several embodiments of the invention, given by way of illustration and not limitation.
    II. EXAMPLES OF CARRYING OUT THE INVENTION 11.1. -Method of characterization of natural rubbers: 11.1. a-Nitrogen level:
    The nitrogen content was measured according to ASTM D 3533-90. 11.1. b-Water content:
    The water content is determined with a Mettler Toledo HB43-S Halogen Desiccator. The desiccator is an automated device that incorporates a cup, a scale and a lid to close the cup. The cup is positioned on the scale. The lid comprises a heating means by a halogen lamp, this heating means being triggered when the lid is folded over the cup. In the cup, we weigh exactly one sample of 10 grams of natural rubber: the device records the corresponding weight "a". The lid is closed to close the cup, which triggers the rise in temperature to reach a target of 160 ° C. When the device detects a weight decrease of less than 0.001 g per minute, the device reads a weight "b". The water content in the sample is given in mass percentage by the following equation:
    Water content (%) = 100 * ((a-b) / a) 11.1. c-Characterization of the macrostructure of natural rubbers by SEC-RI-MALS analysis (Steric Exclusion Chromatography - Differential Refractive Index Detectors - Multiangle Light Scatering Detector):
    The natural rubber samples were dissolved in a solvent (tetrahydrofuran, THF) for 7 days at 25 ° C. at a concentration of 5 mg / ml. The soluble fraction is collected and the concentration is adjusted to 2 mg / ml. After filtration at 0.45 pm, 100 μL are injected into a column set consisting of four columns from Polymer Lab (2 PLgel Mixed A columns and 2 PLgel mixed B columns), the elution solvent being stabilized tetrahydrofuran (250 ppm of BHT), the flow rate being 0.5 mL / min, the temperature of the system being 35 ° C, the analysis time being 90 min. The detection system used is dual: a differential refractometric concentration detector (Wyatt's Optilab T-rEX) and a multi-angle light scattering detector (Dawn Heleos from Wyatt). The data are processed under the Astra software and make it possible to obtain: the number average molecular weight (Mn), the weight average molecular weight (Mw), and the polydispersity (Ip) of the samples analyzed. 11.1. d-Plasticity Retention Index (PRI):
    It is measured according to ASTM D 3194-04. 11.1. e-Mooney Plasticity:
    An oscillating consistometer is used as described in the French standard NF T 43-005 (November 1980). The Mooney plasticity measurement is based on the following principle: the natural rubber is molded in a cylindrical chamber heated to 100 ° C. After one minute of preheating, the rotor rotates within the test tube at 2 revolutions / minute and the useful torque is measured to maintain this movement after 4 minutes of 8 rotations. The Mooney plasticity (ML 1 + 4) is expressed in "Mooney unit" (UM, with 1 UM = 0.83 Newton.meter). II.Z-Example of drying in a press:
    20 g of bottom mud coagulum granules having a water content of greater than 12% and a nitrogen content of 0.41% are compressed, which granules are arranged between two plates of a press arranged horizontally and heated to a given temperature. indicated in Table 1 for each of the tests 1 to 5. A pressure of 150 bar is applied for 1 minute (time that allows to bring the coagulum to the temperature of the press), after which the press is opened very quickly (in less than a second) to remove the pressure on the coagulum and produce adiabatic flash relaxation. The compression and expansion operation is repeated by opening the press according to the same procedure described previously 1 to 3 times, as indicated in Table 1. Between each compression-relaxation cycle, the rubber is folded back on itself to renew the exchange surface.
    After each compression and expansion cycle, the nitrogen content in the natural rubber is measured.
    Table 1
    Tests 1 and 2 are not in accordance with the invention since the coagulum is compressed at a temperature of 150 and 170 ° C respectively. Trials 3 to 5 are in accordance with the invention since the coagulum is compressed at a temperature of 190, 200 and 210 ° C.
    After 3 iterations, all natural rubbers have a water content of less than 0.8%. On the other hand, only the tests in accordance with the invention lead to the production of a natural rubber having a nitrogen content of not more than 0.3%. It is noted that it is necessary, before carrying out the flash adiabatic expansion, to compress the coagulum at a temperature of at least 190 ° C., more precisely at a temperature ranging from 190 ° C. to 210 ° C., in order to obtain a natural rubber with a water content of less than 0.8% and a nitrogen content of not more than 0.3%.
    II.3-Example of drying in an extruder equipped with a die with screw-end holes and a granulator, followed by drying on a vibrating screen:
    An extruder of a bottom-bottom coagulum is fed in the form of granules having a water content of greater than 12% and a nitrogen content of 0.38%. The extruder is a single-screw extruder, it is equipped with a die with screw-end holes and a granulator disposed at the die outlet. The extruder comprises a double jacket, its sheath present in the feed zone of the water evacuation means (grooves, slots, holes). The speed of the screw is 150 rpm, the pressure is 155 bar, the temperature of the coagulum is 194 ° C, the temperature and the pressure being measured by sensors positioned closer to the die, between the die and the end of the screw closest to the die. Extruded out, the coagulum in the form of granules is dried on a hot air vibrating screen at a temperature of 130 ° C for about 5 minutes. The natural rubber is recovered having the following characteristics:
    Water content: 0.4% Nitrogen content: 0.28% MIC: 109
    Mn: 890,000 g / mol Mw: 1,250,000 g / mol ML: 62
    Instead of being dried according to the procedure described above and in accordance with the invention, the same starting coagulum as that used to feed the extruder, also in the form of granules, was dried according to a conventionally conventional process. used for the manufacture of grade TSR20, that is to say a drying in a tunnel under hot air at a temperature ranging from 108 ° C to 125 ° C for 4:30 minutes. The natural rubber resulting from this process has the following characteristics:
    Water content: 0.6% Nitrogen content: 0.38% MIC: 64
    Mn: 582,000 g / mol MW: 898,000 g / mol ML: 71
    It is observed that, unlike the drying method conventionally used for the manufacture of grade TSR20, the process according to the invention makes it possible to obtain a natural rubber which is not only dried (water content less than 0.8%), but also which has a reduced nitrogen content of not more than 0.3%, a weight average molecular weight of more than 1 000 000, and a plasticity retention index of more than 100.
    权利要求:
    Claims (19)
    [1" id="c-fr-0001]
    A method of drying a natural rubber which comprises the steps of: a) providing a wet natural rubber coagulum; b) compressing the coagulum at a temperature of from 190 ° C to 210 ° C; coagulum compressed to an adiabatic flash trigger at a differential pressure of at least 100 bar, d) where appropriate subjecting the coagulum resulting from step c) to convective drying or to one or more iterations of the sequence of steps b ) and c).
    [2" id="c-fr-0002]
    2. The method of claim 1 wherein the differential pressure is at least 150 bar in step c).
    [3" id="c-fr-0003]
    3. Method according to any one of claims 1 to 2 wherein the coagulum is at atmospheric pressure at the end of relaxation.
    [4" id="c-fr-0004]
    4. Method according to any one of claims 1 to 3 wherein step d) is performed.
    [5" id="c-fr-0005]
    The method of any one of claims 1 to 4 wherein step d) is convective drying, preferably in air.
    [6" id="c-fr-0006]
    6. A process according to any one of claims 1 to 5 wherein the convective drying is conducted under air at a temperature of 110 "to 130 ° C.
    [7" id="c-fr-0007]
    7. Method according to any one of claims 1 to 6 wherein the coagulum used in step a) contains a water content greater than 12% by weight.
    [8" id="c-fr-0008]
    8. Method according to any one of claims 1 to 7 wherein the coagulum used in step a) contains a water content greater than 5% by weight.
    [9" id="c-fr-0009]
    9. Method according to any one of claims 1 to 6 wherein the coagulum used in step a) contains a water content ranging from 3 to 5% by weight.
    [10" id="c-fr-0010]
    The method of any one of claims 1 to 9 wherein the coagulum used in step a) is a cup bottom.
    [11" id="c-fr-0011]
    11. Process according to any one of claims 1 to 10 wherein the coagulum used in step a) is in the form of granules.
    [12" id="c-fr-0012]
    12. A method according to any one of claims 1 to 11, which process is implemented with a device comprising a single worm machine and a hot air fluidized bed, the worm machine being an extruder equipped with screw end of a die with holes and a means adapted to cut the coagulum and disposed after the die.
    [13" id="c-fr-0013]
    13. The method of claim 12 wherein the means adapted to cut the coagulum is a granulator.
    [14" id="c-fr-0014]
    14. The method of claim 12 or 13 wherein the extruder comprises a sheath which has in the feed zone of the extruder one or more means for discharging water.
    [15" id="c-fr-0015]
    The method of any one of claims 12 to 14 wherein the extruder is a single screw extruder.
    [16" id="c-fr-0016]
    16. A method according to any one of claims 12 to 15 wherein the extruder comprises a double jacket.
    [17" id="c-fr-0017]
    17. The method of any one of claims 12 to 16 wherein the hot air fluidized bed is a vibrating screen.
    [18" id="c-fr-0018]
    18. Natural rubber having a weight average molecular weight greater than 1000 000 g / mol, a water content of less than 0.8% by mass, a nitrogen content of less than 0.3% by mass and a retention index of plasticity greater than 100.
    [19" id="c-fr-0019]
    19. Natural rubber according to claim 18 wherein the nitrogen content is between 0.2 and 0.3% by weight.
    类似技术:
    公开号 | 公开日 | 专利标题
    EP3464387B1|2020-07-15|Drying process of natural rubber
    US10287367B2|2019-05-14|Process for the removal of rubber from TKS plant matter
    CN110283260B|2021-09-28|Methods for recovering rubber from aged briquettes and aged briquettes comprising plant matter from non-hevea plants
    FR2873896A1|2006-02-10|SOLUBLE SOLUBLE PARTICLE | BASED ON FIBER | FOOD |
    LU87807A1|1991-05-07|IMPROVEMENTS RELATING TO THE PROCESSING OF TOBACCO LEAVES
    EP1915061A1|2008-04-30|Textured pea proteins
    WO2019102107A1|2019-05-31|Method for processing natural rubber
    WO2019102109A1|2019-05-31|Natural rubber
    WO2018224773A1|2018-12-13|Method for decontaminating natural rubber by high-pressure filtration of a wet coagulum of natural rubber
    FR2608171A1|1988-06-17|GRANULE FOR THE MANUFACTURE OF METALLIC MATRIX COMPOSITES AND PROCESS FOR PREPARING THE GRANULE
    FR2478525A1|1981-09-25|PROCESS FOR MANUFACTURING A MOLDED ARTICLE IN A HIGH POLYMER OF ACETYLENE
    WO2019102108A1|2019-05-31|Process for treating a natural rubber
    EP0823917B1|1999-08-25|Polyvinyl alcohol purification process
    FR2574633A1|1986-06-20|Method for extracting manioc | pulp, by dry means, particularly for preparing manioc | flour
    WO2021224568A1|2021-11-11|Method for preparing stabilized natural rubber
    FR2736356A1|1997-01-10|PROCESS FOR OBTAINING A CELLULOSE FORMIATE SOLUTION BY IMPREGNATION THEN MIXING OF CELLULOSE PLATES
    WO2021111082A1|2021-06-10|Method for preparing natural rubber
    RU2616821C1|2017-04-18|Method for processing husk-free sunflower kernels
    FR2599597A1|1987-12-11|Method and installation for obtaining food-grade flour from oil-bearing grains
    FR2821844A1|2002-09-13|PROCESS FOR PREPARING A DIRECTLY COMPRESSIBLE BETA-CYCLODEXTRIN, AND DIRECTLY COMPRESSIBLE BETA-CYCLODEXTRIN THUS OBTAINED
    FR2662802A1|1991-12-06|METHOD FOR CHARACTERIZING THE VISCOELASTIC BEHAVIOR OF A MATERIAL, IN PARTICULAR THE ELASTOMERIC TYPE AND APPARATUS FOR IMPLEMENTING SAID METHOD
    WO2020094992A1|2020-05-14|Method for processing natural rubber
    FR3045609A1|2017-06-23|METHOD OF PURIFYING POLYROTAXANES BASED ON CYCLODEXTRINS
    FR2648371A1|1990-12-21|Method and apparatus for treatment of waste for obtaining shaped self-supporting products
    FR3056922A1|2018-04-06|PARTICULAR METHOD FOR EXTRACTING MOLECULES BY HIGH PRESSURE
    同族专利:
    公开号 | 公开日
    FR3051795B1|2018-06-15|
    EP3464387A1|2019-04-10|
    CN109195997B|2021-01-08|
    WO2017207912A1|2017-12-07|
    US20200317823A1|2020-10-08|
    CN109195997A|2019-01-11|
    EP3464387B1|2020-07-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP2457948A1|2009-07-22|2012-05-30|Bridgestone Corporation|Tire|
    EP2671913A1|2011-02-03|2013-12-11|Bridgestone Corporation|Natural rubber, rubber composition using the same, and tire|
    WO2015028615A1|2013-08-30|2015-03-05|Compagnie Generale Des Etablissements Michelin|Natural rubber modified by an amino acid|WO2020094992A1|2018-11-09|2020-05-14|Compagnie Generale Des Etablissements Michelin|Method for processing natural rubber|
    WO2021111082A1|2019-12-04|2021-06-10|Compagnie Generale Des Etablissements Michelin|Method for preparing natural rubber|
    WO2021224568A1|2020-05-05|2021-11-11|Compagnie Generale Des Etablissements Michelin|Method for preparing stabilized natural rubber|MY137284A|1992-08-05|2009-01-30|Kao Corp|Deproteinized natural rubber and process for producing the same|
    CN100487001C|2004-03-24|2009-05-13|住友橡胶工业株式会社|Protein-free natural rubber latex, process for producing the same and use thereof|
    JP4539177B2|2004-06-04|2010-09-08|住友化学株式会社|Modified diene polymer rubber, method for producing the same, and rubber composition|
    CN101348533A|2008-09-11|2009-01-21|罗天韵|Novel natural rubber drying method|
    JP2010260930A|2009-04-30|2010-11-18|Bridgestone Corp|Method for producing natural rubber suppressing reduction of molecular weight thereof and natural rubber|
    CN107199652B|2011-08-03|2019-09-10|天胶科技有限公司|Natural rubber primary processing device and its method|CN114174399A|2019-06-05|2022-03-11|超越莲花有限责任公司|Tire tread|
    CN110605803B|2019-09-19|2021-09-24|山东京博中聚新材料有限公司|Post-treatment method for producing butyl rubber|
    法律状态:
    2017-05-23| PLFP| Fee payment|Year of fee payment: 2 |
    2017-12-01| PLSC| Search report ready|Effective date: 20171201 |
    2018-05-22| PLFP| Fee payment|Year of fee payment: 3 |
    2019-05-23| PLFP| Fee payment|Year of fee payment: 4 |
    2020-05-22| PLFP| Fee payment|Year of fee payment: 5 |
    2021-05-20| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1654878A|FR3051795B1|2016-05-31|2016-05-31|PROCESS FOR DRYING NATURAL RUBBER|
    FR1654878|2016-05-31|FR1654878A| FR3051795B1|2016-05-31|2016-05-31|PROCESS FOR DRYING NATURAL RUBBER|
    EP17732513.1A| EP3464387B1|2016-05-31|2017-05-30|Drying process of natural rubber|
    US16/304,841| US20200317823A1|2016-05-31|2017-05-30|Process for drying a natural rubber|
    PCT/FR2017/051340| WO2017207912A1|2016-05-31|2017-05-30|Process for drying a natural rubber|
    CN201780033847.1A| CN109195997B|2016-05-31|2017-05-30|Process for drying natural rubber|
    [返回顶部]