KR100477497B1 - Novel Elastomer Composites, Method and Apparatus - Google Patents

Abstract

The elastomeric composite is provided by a novel continuous flow method and apparatus which feeds particulate filler and elastomeric latex into the mixing zone of the coagulation tank to form a flowable mixture that is continuously refluxed from the mixing zone through the coagulation zone to the discharge end of the reactor. Is generated. The particulate filler fluid is supplied under pressure to the mixing zone to form a jet stream, for example, to introduce the elastomer latex fluid sufficiently powerful to substantially solidify the elastomer with the particulate filler before the discharge end. Highly efficient and effective elastomeric coagulation is achieved without the need for a coagulation step which involves exposure to acid or salt solutions and the like. New elastomeric complexes are produced. The novel elastomeric composites can be cured or uncured and combine material properties such as selection of fillers, elastomers, filler loadings and macro-dispersities that were not previously available.

Description

Novel Elastomer Composites, Method and Apparatus

The present invention relates to novel methods and apparatuses for preparing elastomeric composites and novel elastomeric composites prepared using such methods and apparatuses. More specifically, the present invention relates to an elastomeric masterbatch of particulate filler finely dispersed in an elastomer such as a masterbatch composition without a curing agent, a curing agent-retaining base composition and a rubber material, for example carbon black particulate phase finely dispersed in natural rubber. A continuous flow method and apparatus for making elastomeric composites of fillers, and articles made from such masterbatch compositions.

Many commercially important products are made of elastomeric compositions in which particulate fillers are dispersed in any of a variety of synthetic elastomers, natural rubbers or elastomer blends. For example, carbon black is widely used as a reinforcement in natural rubber and other elastomers. It is customary to prepare a masterbatch, ie a premix of various optional additives such as fillers, elastomers and extender oils. Carbon black masterbatches are made of various grades of commercially available carbon blacks varying in both surface area and "structure" per unit weight. Many commercially important products are made of elastomeric compositions of carbon black particulate filler dispersed in natural rubber. Examples of such products are automotive tires in which different elastomer compositions may be used in tread portions, sidewalls, wire schemes and armatures. Examples of other products include engine mounted bushings, conveyor belts, windshield wipers, and the like. While a wide range of performance properties can be achieved using currently available materials and manufacturing methods, there has been an ongoing need in the industry to develop improved elastomeric compositions and to reduce the cost and complexity of current manufacturing methods. In particular, it is known that, for example, macro-dispersion levels, ie the dispersion uniformity of carbon black and other fillers in the elastomer, can significantly affect the performance properties. In elastomer compositions prepared by vigorously mixing natural rubber or other elastomers with carbon black or other fillers (such as in Banbury mixers), an increase in macro-dispersion requires longer and more violent mixing, and thus energy costs The disadvantage is that the manufacturing time is increased. For carbon black fillers of certain surface area and structural properties, some degree of dispersion was not possible or commercially possible using known mixing apparatus and methods. In addition, this extended and more intense mixing also degrades natural rubber by reducing the molecular weight, producing elastomer compounds that are undesirable in certain applications.

It is well known to use carbon blacks with higher or lower structures and surface areas to control the performance properties of elastomeric compositions. Carbon blacks with higher surface areas and lower structures are generally known to improve crack growth and cut-and-fragment properties in addition to wear and other performance properties. However, commercially available mixing methods have not been able to achieve excellent uniformity without dissipating unacceptable natural rubber in dispersing carbon black in elastomers. Indeed, typical carbon black loading levels in natural rubbers such as 45 phr to 75 phr, and oil loadings from 0 phr to 10 phr, carbon blacks of DBPA below 110 cc / 100 g, in particular from about 45 m ² / g to 65 For low structure carbon blacks, such as those having a surface area of m ² / g (CTAB), having undispersed carbon blacks of less than about 1% regardless of duration and strength level (measured by macro-dispersion as follows) It was not possible to achieve the compound. In addition, as described above, in the high energy-consuming and vigorous dry mixing method that is currently widely commercialized, the mastication of the elastomers required to disperse such carbon black results in undesirable destruction of the natural rubber elastomeric polymer chains. do. The resulting reduction in natural rubber molecular weight is undesirable for many industrial fields. For use in, for example, tire tread sections, reduced molecular weight is known to cause an undesirable increase in the so-called rolling resistance of tires.

Theoretical analysis also shows a desirable improvement in certain performance properties of elastomer compositions using high surface area and low structure carbon black, while the molecular weight of natural rubber is well preserved using known physical milling or other mastication methods. Such an elastomeric composition could not be obtained in which satisfactory macro-dispersion of carbon black was achieved. In general, the elastomeric reinforcing properties of carbon black, for example, are known to increase with decreasing particle size of carbon black. However, it is known that an extremely fine carbon black results in an anomalous state in which the expected improvement in properties is not achieved. It is understood that this is at least partly due to the conventional elastomeric compounding process which is unable to sufficiently disperse the carbon black in natural rubber without causing excessive destruction of the elastomeric polymer. Therefore, such carbon black could not take full advantage of the inherent affinity of carbon black and natural rubber for each other.

Since good dispersion in natural rubber compounds has been recognized for some time as one of the most important goals for achieving consistent product performance of good quality, considerable effort has been focused on the development of methods for evaluating the dispersion properties in rubber. Examples of the developed method include the Cabot Dispersion Chart and various image analysis methods. Dispersion characteristics can be defined as the state of mixing achieved. The ideal dispersion of carbon black is such that the carbon black aggregates (or pellets) are broken down into aggregates (performed by distributed mixing) uniformly dispersed between each other (performed by dispersed mixing) and the surfaces of all carbon black aggregates are incorporated into the rubber matrix. Is completely wetted (usually called mixing).

Common problems in the rubber industry that are often related to poor macro-dispersion can be classified into four main categories: product performance, surface defects, surface appearance and dispersion efficiency. The functional performance and durability of carbon black containing rubber compositions such as tensile strength, fatigue life and wear resistance are mainly affected by macro-dispersion properties. In addition, undispersed carbon black can cause surface defects in the finished product, including visual defects. The removal of surface defects present is of great importance for functional reasons in the molded thin film portion and aesthetic and functional for extruded profiles.

Commercial image analyzers, such as the IBAS compact model image analyzer available from the company Kontron Electronik GmbH, Munich, Germany, can be used to measure macro-dispersion of carbon black or other fillers. Typically, in the quantitative macro-dispersion test used in the rubber industry, the critical limit size is 10 microns. Defects larger than about 10 microns in size typically consist of any grit or other contaminant as well as undispersed black or other fillers, which can affect both visual and functional performance. Thus, the measurement of macro-dispersion involves measuring surface defects (generated by fine cutting, extrusion or cutting) of 10 microns or more by the total area of such defects per unit area inspected using an image analysis method. Macro-variance D (%) is calculated as follows.

% Of undispersed area =

Where A _m is the total sample surface inspected, N _i is the number of defects of size D _i , D _i is the diameter of a circle with the same area as the defect (corresponding to the diameter of the circle), and m is the It is a number.

Macro-dispersion of carbon black or other fillers in uncured natural rubber or other suitable elastomers can be assessed using image analysis of cut surface samples. Typically, 5-10 optional images, optionally selected, are taken from the cut surface for image analysis. It is preferable to remove a knife etc. using a numerical filtration method. Thus, cut surface image analysis provides information related to carbon black dispersion properties in natural rubber compounds. In particular, the undispersed area ratio D (%) indicates the quality of the carbon black macro-dispersion. The lower the macro-dispersion characteristic, the more undispersed area ratio increases. Thus, the dispersion characteristics can be improved by reducing the proportion of undispersed area. As mentioned above, the mixing operation directly affects the mixing efficiency and macro-dispersion. In general, better carbon black macro-dispersion in elastomers, for example natural rubber masterbatches, is achieved by longer and more intense mixing. Unfortunately, achieving better macro-dispersion by longer and more intense mixing decomposes the elastomer in which the carbon black is dispersed. This is especially a problem for natural rubbers which are very sensitive to mechanical / thermal decomposition. Longer and more intense mixing using known mixing techniques and devices such as half-blow mixers reduces the molecular weight of the natural rubber masterbatch composition. Thus, it is known that improved macro-dispersion of carbon black in natural rubber is achieved with generally undesired reduction of the corresponding rubber molecular weight.

In addition to dry mixing techniques, a method of continuously feeding latex and carbon black slurries into a stirred coagulation tank is known. This "wetting" technique is commonly used in synthetic elastomers such as SBR. The coagulation tank contains a coagulant, such as a salt, or an aqueous or acidic solution, typically having a pH of about 2.5-4. Latex or carbon black slurries are mixed and solidified into small beads (typically several mm diameter) called wet crumbs in the solidification tank. This crumb and acid effluent are typically separated by vibrator screens or the like. This crumb is then fed into a second stirred tank and washed to achieve neutral or near neutral pH. This crumb is then subjected to additional vibrating screens and drying steps. Modifications to this method have been proposed for the solidification of natural and synthetic elastomers. U. S. Patent 4,029, 633 to Hagopian et al., Assigned to Cabot Inc. as described herein, describes a continuous process for the production of elastomer masterbatches. An aqueous slurry of carbon black is prepared and mixed with natural or synthetic elastomer latex. For this mixture, so-called cream operations are carried out optionally using any of a variety of known cream agents. After the cream process of the carbon black / latex mixture, a solidification process is performed. In particular, the creamed carbon black / latex mixture is introduced into the stream core of the coagulant as one coherent stream. The solid stream of the creamed carbon black / latex mixture is sheared, pulverized and solidified by the stream of coagulant liquid and then passed through the appropriate reaction zone to complete solidification. The remaining process after this solidification step is substantially conventional and includes separation, washing and drying of the crumb from the waste product “serum”. A somewhat similar process is described in US Pat. No. 3,048,559 (Heller et al.). The aqueous slurry of carbon black is blended continuously with natural or synthetic elastomers or latexes. The two streams are mixed under conditions such as involving severe hydraulic disturbances and impacts. The combined stream of carbon black slurry and elastomer latex is then solidified by the addition of an acidic or salt coagulating solution, as in the case of Hapian et al., Supra.

BACKGROUND OF THE INVENTION There have been demands in many industries for elastomeric compounds of particulate fillers dispersed in suitable elastomers, especially carbon blacks dispersed in natural rubber, for example, with improved macro-dispersion. As noted above, improved macro-dispersion can provide significant improvements in aesthetic and functional properties. There is a particular need for novel elastomeric compounds of carbon black in natural rubber, in which improved macro-dispersion is achieved with higher molecular weights of natural rubber. It is an object of the present invention to meet some or all of these dire needs.

Summary of the Invention

According to a first aspect, a method of making an elastomeric masterbatch comprises simultaneously supplying particulate filler fluid and elastomeric latex fluid to a mixing zone of a coagulation reactor. The coagulation zone extends from the mixing zone and preferably the cross-sectional area gradually increases in the downstream direction from the inlet end to the outlet end. The elastomeric latex can be natural or synthetic, and the particulate filler fluid includes carbon black or other particulate filler that is effective to solidify the latex. This particulate filler fluid is preferably supplied to the mixing zone as a continuous high speed jet of injected fluid while the latex fluid is supplied at low speed. The velocity, flow rate and particulate concentration of the particulate filler fluid may cause flow disturbance of the mixture within the high shear mixing of the latex fluid and at least the upstream portion of the coagulation zone to nearly solidify by the elastomeric latex with particulate filler prior to the discharge end. Enough to get up. Thus, according to a preferred embodiment, almost complete coagulation can be achieved without the need to use acidic or salt coagulants.

According to another aspect, the continuous flow method for the production of an elastomer masterbatch is a mixing zone of a coagulation reactor which establishes a continuous and semi-confined flow of a mixture of elastomeric latex and particulate filler in the coagulation zone. Continuous and simultaneous supply of latex fluid and particulate filler fluid. Elastomer masterbatch crumbs in the form of "worms" or globules are released as a nearly constant flow from the discharge end of the coagulation reactor with continuous supply of latex and particulate filler fluid streams to the mixing zone of the coagulation reactor. Enter In particular, the plug-type flow at the discharge end of the coagulation bath and pressure conditions at or near atmospheric or atmospheric pressure are very advantageous to facilitate the control and collection of the elastomer masterbatch product, such as direct or subsequent further processing steps.

According to the aspect of the device, there is provided a means for supplying the elastomer latex fluid to the mixing zone of the coagulation reactor described above, preferably under low pressure and near thin plate type flow conditions, and at a rate sufficient to induce the elastomer latex as described above. Or means for simultaneously supplying particulate filler fluid to the mixing zone under a pressure sufficient to produce a jet of kinetic energy and to allow the mixture flowing downstream from the mixing zone to reach solidification before reaching the discharge end of the coagulation reactor. According to certain preferred embodiments detailed below, the supply channel in the mixing head is integral with the means for supplying the elastomeric latex fluid and the separate means for supplying the particulate filler fluid, respectively, with a nearly tubular member defining a coagulation zone. It is provided. Mixing zones may be provided at the connection points of such feed channels in the mixing head. According to some preferred embodiments, the blend zone may simply extend coaxially with the coagulation zone. The gradual increase in cross-sectional area of the coagulation reactor may be continuous in some preferred embodiments, or may be stepwise in other preferred embodiments. In addition, the coagulation reactor may be provided with an optional component, such as a converter, at its discharge end, as described below. Optional and preferred additional parts of the apparatus of the invention for the continuous flow preparation of the elastomer masterbatch are described in detail below.

According to another aspect, an elastomeric composite is provided as a product of the method or apparatus described above. According to a preferred embodiment, the macro-dispersion levels of particulate fillers which have not been achieved conventionally, conventionally the molecular weight of the elastomer, the particulate loading level, the selection of particulate fillers (e.g. exceptionally high surface area and low structure carbon black fillers) New elastomeric composites are provided, including) and / or other properties. In this regard, the methods and apparatus of the present invention are directed to certain fillers, such as carbon black, having a structure-to-surface ratio DBP: CTAB of 1.2 or less, even 1 or less, with little or no degradation of elastomer molecular weight in elastomers such as natural rubber. Excellent macro-dispersion can be achieved. According to another aspect of the present invention, there is provided an intermediate and final product made of an elastomeric composite produced by the method and apparatus of the present invention.

By the method and apparatus of the present invention, the elastomer masterbatch can be prepared in a continuous flow process comprising a mixture of elastomeric latex and particulate filler fluid at a level of disturbance and flow control sufficient to achieve solidification without the use of traditional coagulants. have. Indeed, it is easy to achieve the great commercial advantage that elastomer masterbatch crumbs, i.e., solidified latexes, are achieved without intense dry chewing of the elastomer with fillers or exposure of latex / particulate liquid compositions to the tank or stream of coagulant. Will be recognized. Thus, the cost and complexity of using an acid coagulant can be eliminated in conventional commercial practice. Prior arts, including premixing of latex and particulates, such as in Heller et al. And Hapian et al., Disclose exposure to conventional coagulants of latex / particulate mixtures, which has the associated cost and disadvantages of waste disposal. Without this, he did not even recognize the possibility of achieving coagulation.

The feed amount of latex fluid and particulate filler fluid into the mixing zone of the coagulation reactor can be precisely metered to achieve high yield with little free latex and undispersed filler in the product crumb at the discharge end of the coagulation reactor. Without being bound by theory, it is presently understood that quasi-single phase systems are established in mixed zones except that solidification solids are formed in and / or downstream of the solidification zone. The extremely high feed rate of the particulate filler fluid into the mixing zone of the coagulation reactor and the rate difference for the latex fluid supply are sufficient by the impact of the particulate filler fluid jet for complete mixing and dispersion and solidification of the particulate into the latex fluid. It is believed that it is important to achieve disturbances, ie sufficient energy of the latex shear. The high mixed energy provides a product masterbatch crumb with good dispersibility with a regulated product supply. Coagulum is produced and formed into the required extrudate.

According to another aspect, the micro-dispersion level of the filler in the elastomer composite, wherein the macro-dispersion level of the filler in the elastomeric composite is less than about 0.2% undispersed area, preferably up to about 0.1% undispersed area An elastomeric complex of is provided. As mentioned above, macro-dispersion of the present invention means macro-dispersity D (%) of carbon black, measured as the percentage of undispersed area of the defect of 10 microns or more. In the natural rubber masterbatch and other elastomeric composites of the present invention, the molecular weight of the natural rubber, ie the MW _sol (weight average) of the _sol portion, is preferably at least about 300,000, more preferably at least about 400,000, and in some preferred embodiments 400,000 to 900,000. The elastomeric composite optionally includes about 0-20 phr, more preferably 0-10 phr of extender oil, and / or other ingredients well known to be optionally used in the combination of natural rubber with carbon black filler. As further described below in connection with preferred and exemplary embodiments, the novel elastomeric composites of the present invention may provide very desirable physical and performance properties. Thus, the present invention provides a significant technical advance.

According to another aspect, certain macro-dispersion levels of carbon black fillers, molecular weight of natural rubber, carbon black loading levels, carbon black properties (including surface area and structure, such as exceptionally high surface area and low structure carbon black fillers) New elastomeric composites are provided that have a combination of new properties not conventionally obtainable, and / or other properties. According to various aspects of the invention, masterbatch compositions and finished and intermediate products made therefrom are provided.

These and other aspects and advantages of the various embodiments of the present invention will be better understood in light of the following detailed description of certain preferred embodiments.

Preferred embodiments are described as follows with reference to the accompanying drawings.

1 shows a schematic flowchart of an apparatus and method for manufacturing an elastomeric masterbatch according to some preferred embodiments.

2 is a schematic front view of a portion of one preferred embodiment consistent with the schematic flow diagram of FIG. 1;

3 is a schematic front view of a portion of another preferred embodiment consistent with the schematic flow diagram of FIG. 1;

4 is a partial cross-sectional view of the mixing head / solidification reactor assembly of the embodiment of FIG. 3.

5 is a partial cross-sectional view corresponding to the drawing of FIG. 4 showing yet another preferred embodiment.

6 is a cross-sectional view taken along line 6-6 of FIG.

7 is a cross-sectional view of a mixing head suitable for use in another preferred embodiment.

8 is a graph showing the surface area and structural properties (CTAB and DBPA) of carbon black used in certain highly preferred masterbatch compositions according to the present invention.

9-25 are graphs showing macro-dispersion, natural rubber molecular weight and / or other properties of the novel elastomeric composite according to the invention comprising the carbon black shown in FIG. 8, in some cases a control sample for comparison It is shown with the data of and shows a significant improvement in the physical and performance properties achieved by the elastomeric composite.

26-29 are graphs showing the morphological properties of carbon black, namely structure (DBPA) and surface area (CTAB), and identifying zones or areas of carbon black suitable for a particular product field (due to such morphological properties). to be.

30 and 31 are graphs showing the macro-dispersion and natural rubber molecular weights of the novel elastomeric composites according to the invention with a control sample for comparison.

It is to be understood that the accompanying drawings are not necessarily accurate in size. Some drawings may be enlarged or reduced for ease of explanation and clarity. Directional indications used in the following description are based on the arrangement of components illustrated in the drawings unless otherwise noted or unclear from the context. In general, devices in accordance with various embodiments of the present invention may be used in a variety of arrangements. Determining the appropriate dimensions and arrangements for the device of the present invention using conventional techniques and taking into account known elements specific to the intended field, such as required manufacturing capacity, material selection, duty cycle, etc. This will be within the capabilities of those skilled in the art given. Reference numerals used in one drawing may be used to indicate the same feature or element in the other drawing.

<Detailed Description of the Preferred Embodiments>

By the method and apparatus of the present invention, the elastomer masterbatch is prepared in a continuous flow process comprising a mixture of elastomeric latex and particulate filler fluid at disturbance levels and flow control conditions sufficient to achieve solidification without the use of traditional coagulants. Can be. Indeed, it is easily commercially viable to achieve elastomer masterbatch crumbs, i.e., to achieve solidified latex, without intense dry chewing of the elastomer with the filler or exposure of the latex / particulate liquid composition to the tank or stream of the coagulant. Will be recognized. Thus, the cost and complexity of using an acid coagulant can be eliminated in conventional commercial practice. Prior arts, including premixing of latex and particulates, such as those described in Heller et al. And Hapian et al., Disclose exposure of the latex / particulate mixture to conventional coagulating liquor, with the associated costs and disadvantages of waste disposal. Without this, they could not even recognize the possibility of achieving coagulation.

The supply amount of latex fluid and particulate filler fluid into the mixing zone of the coagulation reactor can be precisely metered to achieve high yield with little free latex and undispersed filler in the product crumb at the discharge end of the coagulation reactor. Without being bound by theory, it is presently understood that quasi-single phase systems are established in mixed zones except that solidification solids are formed in and / or downstream of the solidification zone. The extremely high feed rate of particulate filler fluid into the mixing zone of the coagulation reactor and the rate difference for latex fluid supply are due to sufficient disturbances due to the complete mixing and dispersal of the particulate into the latex fluid and the collision of the particulate filling fluid jet for solidification, That is believed to be important in achieving sufficient energy of the latex shear. The high mixed energy provides a product masterbatch crumb with good dispersibility with a regulated product supply. Coagulum is produced and formed into the required extrudate.

Certain preferred embodiments of the methods and apparatus for making the novel elastomeric composites disclosed herein are described below. While various preferred embodiments of the present invention may use a variety of fillers and elastomers, some of the following detailed descriptions in terms of methods and apparatus of the present invention include, by way of example, masterbatches comprising natural rubber and carbon black for convenience. Its basic use in the preparation of It will be within the skill of the person skilled in the art given the advantages of the present invention to produce a masterbatch comprising numerous alternative or additional elastomers, fillers and other materials using the methods and apparatus of the present invention in accordance with the principles of operation as follows. In short, this method of preparing an elastomeric masterbatch comprises simultaneously supplying a slurry of carbon black or other filler and a natural rubber latex fluid or other suitable elastomeric fluid to the mixing zone of the coagulation reactor. The coagulation zone extends from the mixing zone and preferably the cross-sectional area gradually increases in the downstream direction from the inlet end to the outlet end. This slurry is preferably supplied to the mixing zone as a continuous high speed jet of injected fluid, while the natural rubber latex fluid is supplied at a relatively low speed. The high velocity, flow rate and particle concentration of the filler slurry is sufficient to cause mixing and high shear of the latex fluid, flow disturbance of the mixture, at least within the upstream portion of the coagulation zone, and to almost completely solidify the elastomeric latex before the discharge end. Thus nearly complete coagulation can be achieved without the need to use acidic or salt coagulants according to preferred embodiments. A preferred continuous flow method for preparing the elastomeric composites is to continuously and simultaneously supply the latex fluid and the filler slurry to the mixing zone of the coagulation reactor and to establish a continuous and unlimited flow of the mixture of latex and filler slurry at the coagulation zone. It involves doing. Elastomeric composite crumbs in "worm" or globular form are discharged from the discharge end of the coagulation bath in a substantially constant flow with a continuous supply of latex and carbon black slurry streams into the mixing zone of the coagulation reactor. In particular, the plug-type flow at the discharge end of the coagulation bath and conditions at or near atmospheric pressure are very advantageous to facilitate the control and collection of the elastomeric composite product, such as direct or successive further process steps. The feed amount of the natural rubber latex fluid and carbon black slurry into the coagulation zone of the coagulation tank can be precisely metered to achieve a high yield with little free latex and undispersed carbon black in the product crumb at the discharge end of the coagulation reactor. . Without theoretical limitations, it is presently understood that quasi-single phase systems are established in the mixed zone except that solidification solids are formed in and / or downstream of the solidification zone. The extremely high feed rate of the carbon black slurry to the mixing zone of the coagulation reactor and the rate of latex fluid supply are sufficiently disturbed by the collision of the particulate filler fluid jet for complete mixing and dispersion of the fine particles into the latex fluid and solidification. It is believed that it is important to achieve sufficient energy of the latex shear. The high mixing energy provides a novel product with good macro-dispersion with a regulated product supply. Coagulum is produced and formed into the required extrudate.

The preferred apparatus and techniques described above for producing the elastomeric composites of the present invention are described in conjunction with the accompanying drawings, wherein the continuous flow method of preparing the elastomer masterbatch is extended and preferably increases gradually from the inlet end to the outlet end. In a coagulation reactor which forms an elongated coagulation zone having a cross-sectional area, it is a continuous process of elastomeric latex, for example natural rubber latex (field latex or concentrate) mixed with filler slurry, for example an aqueous slurry of carbon black. Use an unlimited flow. The term "limiting" flow refers to very advantageous properties. The term used in the present invention is that the flow passage leading to the latex fluid and filler slurry mixed in the coagulation reactor is hermetically or nearly closed upstream of the mixing zone and is open at the opposite downstream end of the coagulation reactor, ie at the discharge end of the coagulation reactor. It means to be. Disturbance conditions in the upstream portion of the coagulation zone continue to be at least quasi-steady, with conditions of near plug flow type at the open discharge end of the coagulation reactor. The discharge end is generally discharged to a suitable collecting means, such as a feed hopper of a dewatering extruder, typically by a simple gravitational drop (in a randomly wrapped or screened flow passage) at or near atmospheric pressure. In the smallest sense. Thus, the semi-limiting flow results in a disturbance gradient extending axially or longitudinally within the minimum portion of the coagulation reactor. Without theoretical limitations, it is currently understood that the coagulation zone is important in that it allows high disturbing mixing and coagulation in the upstream portion of the coagulation reactor with an almost plug-type release flow of solid product at the discharge end. Injection of carbon black or other filler slurry into the continuous jet into the mixing zone continues at the same time as the ease of collection of the elastomer masterbatch crumbs released under substantially plug-type flow conditions and generally at atmospheric pressure at the discharge end of the coagulation reactor. It happens in the form of Similarly, the axial velocity of the slurry, generally through the slurry nozzle from the upstream end of the coagulation zone to the mixing zone, is substantially higher than at the discharge end. The axial velocity of the slurry can typically be hundreds of feet per second as it enters the mixing zone from the axially arranged feed tubes of the small holes according to the preferred embodiments below. In typical applications, the axial velocity of the flow produced at the inlet end of the solidification reactor having an expanded cross-sectional area is, for example, 1.52 to 6.10 m / sec (5 to 20 ft / sec), preferably 2.13 to 4.57 m / sec (7 to 15 ft / sec). In contrast, the axial velocity of the masterbatch crumb product released at the distal end is approximately 0.31 to 3.05 m / sec (1 to 10 ft / sec), more typically 0.61 to 1.52 m / sec (2 to 5 ft) in typical applications. / sec). Thus, the semi-limiting disturbance flow described above causes the natural rubber or other elastomer latex to solidify by mixing with carbon black or other fillers without subsequent treatment in an acid, salt or other coagulant stream or tank and subsequent A very important advantage is achieved in the supply of controlled, preferably semi-molded products from the solidification reactor for the process.

In this regard, to refer to the coagulation reactor as open at the discharging end is to be understood not to mean that the discharging end is necessarily exposed to sight or easily accessible by hand. Instead, it may be permanently or detachably attached to a collecting device such as a diverter (described further below), a dryer or the like, or to a subsequent process device. The discharge end of the coagulation vessel is open, which means that the disturbing flow in the coagulation zone of the coagulation zone under high pressure and closed for any significant rearward (ie upstream) movement in the mixing zone moves or discharges towards the discharge end. It is important to let the pressure and / or velocity gradient set forth above exit from the distal end.

It is also to be understood in this connection that the flow disturbance decreases towards the discharge end along the coagulation reactor. Substantial plug flow of the solid product is achieved depending on factors such as the rate of utilization of the capacity, the choice of materials, etc., prior to the discharge end. References to flows which are almost plug flow at or before the discharge end of the coagulation reactor in view of the fact that the flow at the discharge end consists essentially or entirely of a masterbatch crumb, ie a glob or “warm” of the solidified elastomer masterbatch. Should be understood. This crumb is typically semi-molded according to the internal shape of the solidification zone in that the flow follows the solidification zone where the flow almost becomes a plug flow. The on-going mass of the "warm" or globble moves generally or essentially axially toward the discharging end and has a fairly uniform velocity at any point in time in a given cross section of the solidification zone near the discharging end so that subsequent processing It advantageously has a plug-type flow in such a sense that it is well collected and controlled for. Thus, the mixing aspect of the fluid phase of the present invention can advantageously be performed at steady state or near steady state to create a high level of product uniformity.

A preferred embodiment of the method and apparatus of the present invention is schematically illustrated in FIG. Those skilled in the art will appreciate that various aspects of the system configuration, the choice of components, etc. will depend to some extent on the particular characteristics of the intended application. Thus, factors such as, for example, maximum processing capacity of the system and flexibility in material selection will affect the size and placement of system components. In general, these considerations will be within the scope of those skilled in the art given the advantages of the present invention. The system illustrated in FIG. 1 is shown to include means for supplying natural rubber latex or other elastomeric latex fluid at low pressure and low speed continuously into a mixing zone of a coagulation reactor. More specifically, latex pressure tank 10 is shown to maintain the supply of latex under pressure. Alternatively, a peristaltic pump or series of pumps or latex storage tanks equipped with a series of pumps or other suitable supply means may be used which are adapted to hold the elastomeric latex fluid which is fed via the supply line 12 into the mixing zone of the coagulation reactor 14. . The latex fluid in the tank 10 is maintained in a state such as air or nitrogen pressurization such that the latex fluid is preferably mixed at a line pressure of 10 psig or less, more preferably 2-8 psig, typically about 5 psig. Can be supplied. This latex supply pressure and flow lines, connections, etc. of the latex supply means should be arranged to cause shearing in the low latex fluid as appropriate as possible. Preferably, for example, all flow lines, if present, are smooth with only large diameter turning points and connection points between smooth or flat lines. The pressure is chosen to produce the required flow rate into the mixing zone. Examples of useful flow velocities are about 3.66 m / sce (12 ft / sec) or less.

Suitable elastomer latex fluids include natural and synthetic elastomer latexes and latex blends. Of course, this latex should be suitable for solidification with the chosen particulate filler and for the intended purpose or application of the final rubber product. It is within the ability of one of ordinary skill in the art to select a suitable elastomeric latex or blend of suitable elastomeric latexes for use in the methods and apparatus of the present invention given the advantages of the present invention. Exemplary elastomers include polymers such as rubber, 1,3-butadiene, styrene, isoprene, isobutylene, 2,3-dimethyl-1,3-butadiene, acrylonitrile, ethylene and propylene (e.g. homopolymers, airborne Coalescing and / or terpolymers). The elastomer may have a glass transition temperature (Tg) as measured by differential scanning calorimetry (DSC) from about -120 ° C to about 0 ° C. Examples include, but are not limited to, styrene-butadiene rubber (SBR), natural rubber and chlorinated rubber, polybutadiene, polyisoprene, their derivatives such as poly (styrene-co-butadiene) and any of their oil extended derivatives. It doesn't work. In addition, any blend of the above may also be used. The latex can be present as an aqueous carrier liquid. Alternatively the liquid carrier may be a hydrocarbon solvent. In any case, the elastomer latex fluid should be suitable for controlled continuous feeding into the mixing zone at the proper speed, pressure and concentration. Particularly suitable synthetic rubbers include about 10 such as copolymers of 19 parts of styrene and 81 parts of butadiene, copolymers of 30 parts of styrene and 70 parts of butadiene, copolymers of styrene 43 parts and 57 parts of butadiene, copolymers of 50 parts of styrene and 50 parts of butadiene. A copolymer of from about 70 parts by weight of styrene to about 90 to 30 parts by weight of butadiene; Polymers or copolymers of conjugated dienes such as polybutadiene, polyisoprene, polychloroprene and the like, and styrene copolymerizable with these conjugated dienes, methyl styrene, chlorostyrene, acrylonitrile, 2-vinyl-pyridine, 5- Methyl-2-vinylpyridine, 5-ethyl-2-vinylpyridine, 2-methyl-5-vinylpyridine, alkyl-substituted acrylate, vinyl ketone, methyl isopropenyl ketone, methyl vinyl ether, alphamethylene carboxylic acid and Copolymers with esters thereof and ethylene group-containing monomers such as their amides such as acrylic acid and dialkylacrylic acid amides. Also suitable for use in the present invention are copolymers of ethylene and other higher alpha olefins (propylene, butene-1 and pentene-1). As will be mentioned further below, the rubber compositions of the present invention may comprise hardeners, linking agents and optionally various processing aids, oil extenders and antidegradants in addition to elastomers and fillers.

In this regard, the elastomer composites of the present invention should be understood to include vulcanizing compositions (VR), thermoplastic vulcanizates (TOV), thermoplastic elastomers (TPE) and thermoplastic polyolefins (TPO). TPV, TPE and TPO materials are further subdivided by their ability to be extruded and molded several times without loss of performance properties. Thus, in preparing the elastomeric composites, one or more curing agents may be used, such as, for example, sulfur, sulfur donors, active agents, accelerators, peroxides, and other systems used to vulcanize the elastomeric composition.

Where the elastomer latex comprises a natural rubber latex, the natural rubber may comprise in situ latex or concentrate (eg, produced by evaporation, centrifugation or creaming). Natural rubber latex should of course be suitable for solidification by carbon black. Latex is typically provided as an aqueous carrier liquid. Alternatively the carrier liquid may be a hydrocarbon solvent. In any case, the natural rubber latex fluid should be suitable for mixing controlled continuous feeds at appropriate rates, pressures and concentrations. The well-known instability of natural rubber latex is advantageous in that it is placed at a relatively low pressure and low shear through the system until it meets the very high velocity and kinetic energy of the carbon black slurry in the mixing zone and is transported to the above-mentioned limiting disturbance flow. Is adapted. For example, in certain preferred embodiments, the natural rubber has a pressure of about 5 psig, in the range of 0.91 to 3.66 m / sec (3-12 ft / sec), more preferably 1.22 to 1.83 m / sec (4-6 ft / sec) It is fed to the mixing zone at the feed rate of. Selection of a suitable latex or latex blend will be within the capabilities of those skilled in the art given the advantages of the present invention and given the knowledge of selection criteria generally well known in the industry.

Particulate filler fluid, for example carbon black slurry, is fed via feed line 16 to the mixing zone at the inlet end of the coagulation reactor 14. This slurry may comprise any suitable filler in a suitable carrier fluid. The choice of carrier fluid will usually depend on the choice of particulate filler and the system parameters. Both aqueous and non-aqueous liquids can be used, and in many embodiments water is preferred in view of cost, availability, and suitability for use in the production of carbon black and other filler slurries.

When carbon black filler is used, the choice of carbon black will usually depend on the intended use of the elastomer masterbatch product. Optionally, the carbon black filler may also include any material that can be slurried and fed into the blending zone according to the principles of the present invention. Examples of suitable additional particulate fillers are fillers including conductive fillers, reinforcing fillers, short fibers (typically having an L / D ratio of 40 or less), flakes, and the like. Thus, exemplary particulate fillers that can be used in the preparation of the elastomer masterbatch in accordance with the methods and apparatus of the present invention are chemically functional carbon such as carbon black, humed silica, precipitated silica, coated carbon black, organic groups attached thereto. Black and silicon treated carbon black, and these may be used alone or in combination with each other. Suitable chemically functional carbon blacks include those disclosed in International Application PCT / US95 / 16194 (WO9618688), which is incorporated herein by reference. In silicon treated carbon blacks, silicon-containing species such as silicon oxides or carbides are distributed as intrinsic portions of carbon black at least through portions of the carbon black aggregates. Ordinary carbon blacks exist in aggregate form, and each aggregate consists of a single phase of carbon. This phase can exist in the form of graphite crystals and / or amorphous carbon, usually a mixture of these two forms. As described elsewhere, the carbon black aggregates can be modified by depositing silicon containing species such as silica on at least the surface portion of the carbon black aggregates. The result can be described as silicon coated carbon black. Materials described as siliconized carbon black are coated or otherwise modified but are not carbon black aggregates that actually represent other types of aggregates. In silicon treated carbon black, the aggregate comprises two phases. One phase is carbon, which is present as graphite crystals and / or amorphous carbon, while the second phase is silica (and possibly other silicon containing species). Thus, the phase of the silicon containing species of silicon treated carbon black is an intrinsic portion of the aggregate, which is distributed through at least a portion of the aggregate. It will be appreciated that the composite phase aggregates are quite different from the silica coated carbon blacks described above, which consist of preformed single phase carbon black aggregates having silicon-containing species deposited on their surfaces. Such carbon black may be surface treated to impart silica functionality to the surface of the carbon black aggregate. In this process, the aggregates present are treated to deposit or coat silica (possibly other silicon containing species) on at least a portion of the surface of the aggregates. For example, an aqueous sodium silicate solution can be used to deposit amorphous silica on the surface of the carbon black aggregates in 6 or more high pH aqueous slurry, as described in Japanese Patent Laid-Open No. 63-63755 (Kokai). have. More specifically, carbon black can be dispersed in water to obtain an aqueous slurry consisting, for example, of 5% by weight carbon black and 95% by weight water. This slurry is heated to about 70 ° C. or higher, for example 85-95 ° C., and adjusted to a pH of 6 or higher such as 10-11 to become an alkaline solution. A separate preparation is made of a sodium silicate solution containing the amount of silica required to be deposited on carbon black and an acidic solution that brings the sodium silicate solution to neutral pH. Sodium silicate and acidic solution are added dropwise to the slurry, which is maintained at its starting pH value by a suitable acidic or alkaline solution. The temperature of the solution is also maintained. The suggested rate of addition of the sodium silicate solution will determine the dropwise addition to add about 3% by weight of silicic acid per hour relative to the total amount of carbon black. This slurry should be stirred for several minutes (eg 30 minutes) to several hours (ie 2-3 hours) during and after addition. In contrast, silicon-treated carbon black can be obtained by producing carbon black in the presence of volatile silicon-containing compounds. Such carbon blacks are preferably produced in modular or staged carbon black reactors with concentrated diameter zones, feed zones of limited diameter and combustion zones followed by reaction zones. The cooling zone is located downstream of the reaction zone. Typically, the cooling fluid, generally water, is sprayed into a newly formed stream of carbon black particles flowing from the reaction zone. In the production of silicon treated carbon black, the volatile silicon-containing compound described above is introduced into the carbon black reactor at the point upstream of the cooling zone. Useful compounds are compounds that are volatile at carbon black reactor temperatures. Silicates such as, for example, tetraethoxy orthosilicate (TEDS) and tetramethoxy orthosilicate; Silanes such as tetrachlorosilane and trichloro methylsilane; And colatile silicone polymers such as octamethylcyclotetrasiloxane (OMTS). The flow rate of the volatile compounds will determine the weight percent silicon in the treated carbon black. The weight percent silicon in the treated carbon black is typically about 0.1 to 25%, preferably about 0.5 to about 10%, more preferably about 2 to about 6%. Volatile compounds may be premixed with the carbon black forming feed and introduced into the reaction zone with the feed. In addition, volatile compounds may be introduced separately into the reaction zone either upstream or downstream from the feed injection point.

As noted above, additives may be used and in this connection useful binders for linking silica or carbon black are expected to be useful for siliconized carbon black. Carbon black and many suitable additional particulate fillers are commercially available and known to those skilled in the art.

The choice of particulate filler or mixture of particulate filler will usually depend on the intended use of the elastomeric masterbatch product. Particulate fillers used in the present invention may comprise any material that can be slurried and fed into the mixing zone according to the principles of the present invention. Examples of suitable particulate fillers are fillers including conductive fillers, reinforcing fillers, short fibers (typically having an L / D ratio of 40 or less), and the like. In addition to carbon black and the above silica type fillers, the fillers may be made of polymers such as clay, glass, aramid fibers and the like. The selection of suitable particulate fillers for use in the methods and apparatus of the present invention given the advantages of the present invention is within the ability of those skilled in the art, and any filler suitable for use in the elastomer composition using the techniques of the present invention It is anticipated that it may be incorporated into the complex. Of course, blends of the various particulate fillers described in the present invention may be used.

Preferred embodiments of the invention according to FIG. 1 are particularly suited for the preparation of particulate filler fluids comprising carbon black aqueous slurries. According to the known principle, it will be understood that carbon black having a low surface area per unit weight should be used at a higher concentration in the particulate slurry to achieve the same coagulation efficacy as a lower concentration of carbon black having a higher surface area per unit weight. . The stirred mixing tank 18 receives water and carbon black, such as optionally pelletized carbon black, to make the initial mixture fluid. This mixture fluid enters the fluid line 22, through the outlet 20, in which pump means 24, such as a diaphragm pump, are equipped. Line 28 passes the mixture fluid through colloid mill 32 or alternatively passes through inlet 30 to a pipeline mill. The carbon black is dispersed in the aqueous carrier liquid to form a dispersion fluid and passes through the outlet 31 and the fluid line 33 to the homogenizer 34. A pump means 36, preferably consisting of a gradual cavity pump or the like, is provided in line 33. The homogenizer 34 disperses the carbon black more finely in the carrier liquid to form a carbon black slurry, which is supplied to the mixing zone of the coagulation reactor 14. It has a suction port 37 in fluid communication with the line 33 from the colloid mill 32. Preferably, homogenizer 34 may be comprised of a trademarked "Microfluidizer" system commercially available from, for example, Microfluidics International Corporation, Newton, Massachusetts, USA. Also suitable are models MS18, MS45 and MC120 series homogenizers available from the APV Homogenizers department of the company [APV Gaulin, Inc., Wilmington, Massachusetts, USA]. Other suitable homogenizers are commercially available and will be apparent to those skilled in the art given the advantages of the present invention. Typically, carbon black in water prepared according to the system described above has at least about 90% aggregates up to about 30 microns, more preferably at least 90% aggregates up to about 20 microns. Preferably, the carbon black is ground to an average size of 5-15 microns, for example about 9 microns. The outlet 38 directs the carbon black slurry from the homogenizer through the feed line 16 to the mixing zone. This slurry can reach 10,000 to 15,000 psi in the homogenization step and exit the homogenizer at about 600 psi or more. Preferably, a high carbon black content is used to reduce the work of removing excess water or other carriers. Typically, about 10 to 30 weight percent carbon black is preferred. Those skilled in the art will appreciate that the carbon black content (wt%) of the slurry and the slurry flow rate into the blending zone, when given the advantages of the present invention, will be combined with the natural rubber latex flow rate into the mixing zone to achieve the required carbon black content (phr) in the masterbatch. You will see that it must be harmonious. This carbon black content is chosen according to known principles such that material and performance properties suitable for the intended application of the product are achieved. Typically, for example, a carbon black having a CTAB value of 10 or more is used in an amount sufficient to achieve a carbon black content in the masterbatch of at least about 30 phr.

Preferably the slurry is used for the preparation of the masterbatch as soon as it is prepared. Fluid conduits and any holding tanks or the like that carry the slurry should establish or maintain a condition that substantially preserves the carbon black dispersion in the slurry. That is, substantial reagglomeration or fixation of particulate fillers in the slurry should be prevented or reduced to a very practical degree. Preferably, all flow lines are smooth and have interconnections between the smooth lines. Optionally, an accumulator may be used between the homogenizer and the mixing zone to reduce variations in slurry pressure or speed at the slurry nozzle tip of the mixing zone.

As noted above, the natural rubber latex fluid or other elastomeric latex fluid passed through the feed line 12 into the blend zone under suitable process parameters, and the carbon black slurry fed into the blend zone through the feed line 16 are novel. Elastomer composites, in particular elastomer masterbatch crumbs can be prepared. Means are also provided for incorporating the various additives into the elastomer masterbatch. The additive fluid comprising one or more additives may be fed to the mixing zone as a separate feed stream. In addition, one or more additives may be premixed with the carbon black slurry, or more typically the elastomer latex fluid, if appropriate. In addition, the additives may be continuously mixed into the masterbatch, for example by dry mixing techniques. Numerous additives are known to those skilled in the art, for example antioxidants, antiozonants, plasticizers, process aids (eg liquid polymers, oils, etc.), resins, flame retardants, extender oils, brighteners, any mixtures thereof. General uses and selection of such additives are well known to those skilled in the art. Their use in the system of the present invention will be readily understood by the advantages of the present invention. According to some other embodiments, hardeners can be incorporated in a similar manner to produce curable elastomeric composites that can be referred to as curable base compounds.

Mix zone / solidification zone assemblies are described in more detail below. The elastomer masterbatch crumb passes from the discharge end of the coagulation vessel 14 to an appropriate drying apparatus. In the preferred embodiment of FIG. 1, the masterbatch crumb undergoes multiple stages of drying. It first passes through the dewatering extruder 40 and then moves to the dry extruder 42 via a conveyor or simple gravity drop or other suitable means 41. In a typical preferred embodiment consistent with the one illustrated in FIG. 1 for producing a natural rubber masterbatch with carbon black filler, the dehydration / drying operation typically results in a water content of about 0 to 1% by weight, more preferably 0 to 0.5. Will be reduced by weight. Suitable dryers are well known and commercially available, for example extrusion dryers, fluid bed dryers, heated air or other oven dryers, such as French mills available from French Oil machinery Co., Piqua, Ohio, USA. Etc.

The dried masterbatch crumb from the dry extruder 42 is conveyed to the baler 46 by the cooling conveyor 44. This baler is an optional and advantageous part of the apparatus of FIG. 1, in which the dried masterbatch crumb is compressed in a chamber to form a stable block or the like. Typically, elastomer masterbatches in amounts of 25 to 75 pounds are compressed into blocks or bales for transportation, further processing, and the like. Alternatively the product is provided in pellets, for example by cutting of the crumbs.

The dimensions and specific design features of the solidification reactor 14, including the mixing zone / solidification zone assembly suitable for the embodiment according to FIG. 1, depend in part on design elements such as the required treatment capacity, the choice of material to be treated, and the like. One preferred embodiment is shown in FIG. 2, where the coagulation reactor 48 has a mixing head 50 attached to the coagulation zone 52 such that the coagulation reactor 48 is fluid tight at the connection point 54. 2 shows a first subsystem 56 for feeding the elastomer latex into the mixing zone, a subsystem 57 for feeding the carbon black slurry or other particulate filler fluid into the mixing zone, and optional additional fluid into the mixing zone, The subsystem 58 for supplying pressurized air or the like is schematically shown. Mixing head 50 is shown having three feed channels 60, 61, 62. Feed channel 60 is provided for natural rubber latex fluid and feed channel 62 is provided for direct supply of gas and / or additive fluid. With respect to the preferred embodiment using direct injection of additives, an important advantage is achieved with regard to hydrocarbon additives, or more generally water immiscible additives. Although it is well known to use emulsion mediators to produce additive emulsions suitable for pre-blending with elastomer latexes, preferred embodiments according to the invention using direct injection of additives are conventionally used in emulsion formation as well as the need for emulsion mediators. Eliminate the need for devices such as tanks, dispersing devices, and the like. Thus, reduction of manufacturing cost and complexity is achieved. As will be described further below, the feed channel 61, which is a passage through which the slurry is fed into the mixing zone, is preferably coaxial with the mixing zone and the solidification zone of the coagulation reactor. Although only one feed channel is shown to receive elastomeric latex fluid, any suitable number of feed channels may be disposed around the central feed channel, which is the passage through which the slurry is fed into the mixing zone. Thus, for example in the embodiment of FIG. 2, a fourth supply channel can be provided which is a passage through which ambient air or high pressure air or other gas is supplied to the mixing zone. Compressed air can be similarly injected through the central axis feed channel 61 together with the slurry. The auxiliary feed channel can be closed temporarily or permanently when not in use.

The solidification zone 52 of the solidification reactor 48 is shown having a first portion 64 having an axial length that can be selected according to the design object of the particular application desired. Optionally, the coagulation zone can have a constant cross-sectional area over all or almost all axial lengths. Thus, for example, a coagulation reactor can define a simple, straight-line disturbing flow channel from the mixing zone to the discharge end. However, preferably, as can be seen from the foregoing reasons and in the preferred embodiments illustrated in the figures, the cross-sectional area of the coagulation zone 52 gradually increases from the inlet end 66 to the discharge end 68. More specifically, the cross-sectional area increases from the inlet end to the outlet end in the longitudinal direction. In the embodiment of FIG. 2, the cross-sectional area is gradually increased in the sense that the constant cross-sectional area 64 is continuously increased. The description of the diameter and cross-sectional area of the coagulation vessel (or more suitably the zone of coagulation defined in the coagulation vessel) and other components means the cross-sectional area of the open flow passage and the inner diameter of such flow passage unless otherwise noted.

The elastomeric composite, in particular the solidified elastomer latex in the form of a masterbatch crumb 72, is shown to be released from the coagulation reactor 48 through the converter 70. The diverter 70 is an adjustable conduit attached to the coagulation reactor at the discharge end 68. It can be adjusted to selectively pass the elastomer masterbatch crumb 72 to any other receiving position. This feature advantageously facilitates the removal of the masterbatch crumbs from the product stream, for example in the early stages of manufacturing operations when the instability of the test or initial process can produce temporarily poor products. The converter also provides design flexibility to direct the product from the coagulation reactor to another post process passage. According to the preferred embodiment of FIG. 1, the masterbatch crumb 72 discharged from the coagulation reactor 48 through the converter 70 is shown to be received by the dryer 40.

The cross-sectional dimension of the coagulation reactor 48 appears to increase at the overall angle α between the inlet end 66 and the outlet end 68. The angle α is greater than 0 degrees, in a preferred embodiment 45 degrees or less, more preferably 15 degrees or less, most preferably 0.5-5 degrees. The angle α is shown at half angle in the sense that it is measured from the central longitudinal axis of the coagulation zone at the end of the coagulation zone to point A of the outer circumferential surface of the coagulation zone. In this regard, it is to be understood that the cross-sectional area of the upstream portion of the coagulation reactor, ie the portion near the inlet end 66, increases slowly enough to achieve a semiforming of solidification, preferably in accordance with the principles described above. Too large angle expansion of the coagulation zone may result in an elastomer masterbatch that is not manufactured in the form of a desired crumb of a globble or worm and does not result in a simple spray through the coagulation reactor. Increasing the aperture of the coagulation bath too slowly may, in some embodiments, lead to feed to the mixing head and congestion or blockage of the reaction product. In the downstream portion of the solidification zone where the latex solidifies and the flow is essentially plug flow, the solidification zone can extend with or without an increase in cross-sectional area. Thus, the description of the solidification zone in a preferred embodiment with increasing cross-sectional area should be understood to basically refer to that portion of the solidification zone where the flow is not substantially plug flow.

The cross-sectional area of the coagulation zone (ie, at least the upstream portion thereof, as directly mentioned above) may increase stepwise rather than in the continuous form illustrated in the embodiment of FIG. 2. In the embodiment illustrated in FIG. 3, a continuous flow system for producing an elastomer masterbatch according to the method and apparatus of the present invention is shown to include a mixing head / solidification zone assembly in which the cross section of the solidification zone increases stepwise. have. Preferably, in this stepped embodiment, the individual cross section of the solidification zone has a connection point that is equal to the adjacent portion. That is, in contrast to the sharp and instantaneous increase in diameter from one part to the adjacent part, they combine to form a smooth, generally continuous solidification zone surface. The solidification zone of FIG. 3 increases in three stages so that there are four different portions or holders 74-77. Consistent with the design principles described above, the cross-sectional area of the solidification zone 53 increases from the inlet end 66 to the point A of the discharge end 68 at an overall angle to achieve the required flow control in the upstream portion of the solidification reactor. The first portion 74 comprises (a) a constant diameter portion of the mixing head 50 immediately downstream of the mixing zone, (b) an equal or similar diameter portion connected to the connection point 54 at the inlet end 66. Can be taken. This first part has a constant cross-sectional area D ₁ and an axial dimension or length L ₁ . The length L ₁ in this first portion 74 is three times or more, more preferably five times or more and most preferably about 12 to 18 times larger than the diameter D ₁ . Typically this portion is about 15 times the length of D ₁ . Each successive portion preferably has a constant cross sectional dimension and approximately twice the cross sectional area than the preceding (ie upstream) portion. Thus, for example, portion 75 has a constant cross-sectional dimension and a cross-sectional area twice that of portion 74. Similarly, the cross-sectional area of the portion 76 is twice the portion 75 and the cross-sectional area of the portion 77 is twice the portion 76. In each portion 75-77 the length is preferably at least three times its diameter, more preferably about three to seven times and generally about five times larger. Thus, for example, the longitudinal dimension L ₃ in the portion 76 is preferably about five times the diameter D ₃ .

The mixing head and solidification zone assembly corresponding to the embodiment of FIG. 3 is shown in FIG. 4 in partial cross-sectional view. The mixing head 50 is integral with the solidification zone expander 53 through the coupling portion 54. This results in a mixing zone where the multiple feed channels 60, 61, 62 form together with an elongated substantially cylindrical channel 80 having an axis substantially the same as the portion of the solidification zone in the dilator 53. define. It can be seen that precisely defining the boundaries of the blend zone and / or the solidification zone is not essential to the operability of the methods and apparatus disclosed herein. Many modifications are possible in the design of the flow channel junction zone as will be apparent to those skilled in the art provided the advantages of the present disclosure. In this regard, as a generally preferred guide, in the embodiment of the type described in FIG. 4, for example, the slurry tip 67 is generally the starting point of the cylindrical portion 80 which is approximately longitudinally concentrated at the junction of the feed channel. Is upstream. In this embodiment, the minimum cross-sectional area, preferably defined as a virtual cone from the beginning of the cylindrical portion 80 to the circumferential length from the slurry tip 67, is advantageously greater than or at least greater than the cross-sectional area of the latex feed channel 60. same. Preferably, both the channel 80 and at least an upstream portion of the coagulation zone where the turbulent flow is present prior to a fairly complete solidification of the elastomer latex have both a circulating cross section.

The supply means of the carbon black slurry or other particulate filler fluid comprises a feed tube 82 extending substantially in parallel with the mixing chamber and extending into the inlet or slurry nozzle tip 67 which is open towards the coagulation zone. can see. This is a very advantageous feature of the preferred embodiments discussed herein. As described above, the carbon black slurry is supplied to the mixing zone at a very high speed relative to the feed rate of the latex, and the axial arrangement of the narrow inner diameter supply tube 82 causes the turbulence to proceed significantly. The diameter D _m of the channel 80 (as described above is preferably substantially the same as the diameter D ₁ of the portion immediately following the cross section 74 of the coagulation zone) is preferably 2 of the inner diameter of the slurry feed tube 82. Or more, more preferably about 4 to 8 times the diameter of the feed tube 82, typically about 7 to 8 times its diameter. The feed tube 82 appears to form a leak-free seal with the inlet 83 at the upstream end of the feed channel 61 of the mixing head 50. The diameter of the axial feed tube 82 is largely determined by the required volume flow rate and axial velocity of the slurry as it passes through the slurry nozzle tip 67 into the mixing chamber. The volume and speed corrected or required can be readily determined by those skilled in the art provided the benefit of the present disclosure and will be partly a function of the concentration and selection of the material. Embodiments in which the feed tubes for carbon black slurries, as described and disclosed herein, can be removed, provide the desired flexibility to produce different masterbatch compositions at different times. The feed tube used in one production experiment can be removed and replaced with a large or small aperture tube suitable for subsequent production. In terms of pressure and velocity when the slurry is present in the feed tube, it may be referred to as a spray or jet into the mixing zone. At least in certain embodiments this should be understood to mean high speed injection of the slurry into areas that are already substantially filled with fluid. Thus, this is spraying in the sense of immediate dispensing when passing through the slurry nozzle tip, and not necessarily spraying in the sense of freely moving material droplets in a simply spreading trajectory.

Additional feed channels 60 and 62 can be seen to form junctions 84 and 85 with feed channel 60 and downstream channel 80 at angle β, respectively. The angle β can have a value above 0 ° and below 180 ° in many embodiments. Typically, β may be between 30 ° and 90 °, for example. It may be desirable to avoid negative pressure, ie, cavitation of the latex fluid, when intrained by the high speed slurry exiting the slurry nozzle tip 67, which adversely results in inconsistent mixing which results in inconsistent masterbatch products. Because you can. Air or other gas may be injected or supplied into the mixing zone to assist in breaking any such vacuum. In addition, an extended feed line for natural rubber latex leading to the inlet 86 of the feed channel 60 acts as a latex fluid reservoir. In the preferred embodiment of FIG. 4, the latex feed channel 60 crosses the mixing zone adjacent the slurry nozzle tip 67. However, the latex feed channel may alternatively cross upstream or downstream of the mixing channel of the slurry nozzle tip 67.

Carbon black slurry or other particulate filler fluid is typically supplied to feed tube 82 at a pressure of at least about 300 psig, such as at least about 1000 psig, such as about 500 to 5000 psig. Preferably the liquid slurry is at least 30.48 m / sec (100 ft / sec), preferably from about 30.48 m / sec to about 243.84 m / sec (about 100 to about 800 ft / sec), more preferably about 60.96 m Per second to 152.4 m / sec (about 200-500 ft / sec), for example about 106.68 m / sec (about 350 ft / sec) or more, through the slurry nozzle tip 67 to the mixing zone. Arrow 51 in FIG. 4 shows the general flow direction of the elastomeric latex and auxiliary feed material through feed channels 60 and 62 into channel 80 below slurry nozzle tip 67. Thus, the slurry and latex fluid are fed to the mixing zone at very different feed stream rates, according to the numbers disclosed above. While not wishing to be bound by theory, it is understood that the differential feeding achieves latex shear conditions in the blend zone resulting in good macro-dispersion and coagulation.

Alternative preferred embodiments are described in FIGS. 5 and 6, in which the single axial feed tube 82 is replaced by multiple feed tubes 90-92 extending in the axial direction. More feed tubes may be used, for example up to about 6 or 8 axially extended feed tubes. Advantageously, production flexibility is achieved by using different feed tubes of different diameters to produce different compositions. In addition, multiple feed tubes can be used simultaneously to achieve good turbulence within the mixing zone and the solidification zone of the coagulation reactor.

An alternative embodiment of the mixing head is described in FIG. 7. Mixing head 150 appears to define mixing zone 179. The axial feed channel 161 houses a feed tube 182 adapted to feed carbon black slurry or other particulate filler fluid into the mixing chamber 179 at high speed. The central aperture in feed tube 182 may appear to terminate at slurry nozzle tip 167. The constant diameter nozzle portion 168 is immediately upstream of the slurry nozzle tip 167 and leads to a larger aperture area 169. Preferably, the axial dimension of the portion 168 is about 2 to 6 times its diameter, for example about 5 times. The second feed channel 160 forms a junction 184 with the mixing zone 179 at an angle of 90 ° to feed the elastomer latex fluid into the mixing zone. The cross sectional diameter of the latex fluid supply channel 160 is significantly larger than the cross sectional diameter of the slurry nozzle tip 167 and the portion 168. Without wishing to be bound by theory, the axial expansion of the nozzle land 168, coupled with an enlarged diameter aperture region upstream of the nozzle portion, is advantageous for the flow of slurry through the feed tube 182 to the mixing zone 179. It is believed to provide stability. The aperture of the feed tube 182 was found to work well with the 20 ° chamfer, ie, the conical region 169 extending upstream at an angle of about 20 °. Downstream of the blend zone 179 is an extended solidification zone. Consistent with the principles discussed above, the solidification zone only needs to extend to the edges. That is, its axial dimension should only be longer than its diameter. However, a progressively increased coagulation zone is used.

As discussed above, coagulation of the elastomer masterbatch is considerably completed at or before the end of the coagulation reactor. That is, coagulation takes place in the coagulation zone of the coagulation reactor without the need to add a stream such as coagulant solution. This does not exclude the possibility that some early solidification occurs in the blend zone. The blend zone can be considered an extended part of the coagulation zone for this purpose. In addition, the control for solidified solidification prior to the elastomer masterbatch discharged from the solidification reactor does not mean precluding the possibility of subsequent processing and subsequent processing steps for a variety of purposes appropriate to the intended use of the end product. In this regard, in a preferred embodiment of the novel process disclosed herein using natural rubber latex, the significantly completed coagulation is at least about 95%, preferably at least about 97%, most preferably of the rubber hydrocarbon of the latex. At least about 99% by weight solidifies.

The methods and devices disclosed and described herein produce elastomeric composites with good physical and performance properties. The novel elastomeric composites of the present invention include the masterbatch compositions produced by the methods disclosed above, as well as intermediate compounds and final products made from such masterbatch compositions. Surprisingly, elastomeric masterbatches can be prepared using natural rubber latexes (latex concentrates or field latexes), together with various grades of carbon black fillers, with excellent physical and performance properties. At present, carbon black for a wide range of commercial uses for products such as tire treads, as well as carbon black previously considered unsuitable for commercial use in known manufacturing equipment and methods, have been used successfully. The novel elastomers disclosed herein are inadequate because of their high surface area and low structure that make them attainable (or attain) acceptable levels of macro-dispersion at ordinary commercial loading levels for carbon black and make them impractical to preserve the molecular weight of the elastomer. Very preferred for masterbatch compositions. Such elastomeric composites have been found to have good dispersion of carbon black in natural rubber with good preservation of the molecular weight of the natural rubber. In addition, these advantageous results are achieved without the need for a coagulation step associated with the treatment tank or stream of the acid solution or other coagulant. Thus, the cost and complexity of this coagulant treatment can be avoided as well as the need to treat the effluent stream from this operation.

Previously known dry chewing techniques cannot achieve the same dispersion of such fillers without significant molecular weight reduction, and therefore cannot produce novel natural rubber masterbatch compositions prepared according to certain preferred embodiments of the present invention. In this regard, the novel elastomeric composites have good macro-dispersity of carbon black in natural rubber, and also carbon black having a high molecular weight of natural rubber having a structure-to-surface area ratio (DBPA: CTAB) of less than 1.2, even less than 1.0. Is initiated. Known mixing techniques of the past do not achieve the macro-dispersity of such good carbon blacks without significant molecular weight reduction of natural rubber, and thus do not produce the novel masterbatch compositions and other elastomeric composites of the present invention. According to the present disclosure, preferred novel elastomeric masterbatch compositions with large distribution levels of carbon black that have not been achieved previously may be used in place of previously known masterbatches having poor macro-dispersity. Thus, the masterbatch disclosed herein can be incorporated into the cured compound according to known techniques. These new cured compounds have been found to have fairly good physical and performance properties in some cases, generally similar to those of comparable cured compounds comprising a masterbatch of poor macro-dispersity. However, masterbatches can be made according to the present invention with reduced mixing time, reduced energy input, and / or other cost savings.

In particular, with regard to certain preferred embodiments, natural rubber latex and carbon black filler masterbatches with good physical and performance properties can be prepared. The excellent macro-dispersity of carbon black uses exceptionally high surface area and low structure carbon black for a sufficient time and at a sufficient strength level to achieve the same degree of carbon black dispersion, without decomposition of the natural rubber caused by dry chewing. Is also achieved. In this regard, new natural rubber masterbatch compositions are particularly advantageous in which a high degree of dispersion is achieved using carbon blacks having a structure-to-surface area ratio (DBPA: CTAB) of less than 1.2, even less than 1.0. As used herein, the carbon black structure can be measured as a dibutyl phthalate adsorption amount (DBPA) value, according to the procedure disclosed in ASTM D2414, which is expressed in DBPA cubic centimeters per 100 grams of carbon black. Carbon black surface area can be measured by CTAB expressed in square meters per gram of carbon black, according to the procedure disclosed in ASTM D3765-85. Thus, a novel natural rubber masterbatch with previously unachievable combinations of physical properties such as molecular weight distribution and filler dispersion level and / or incorporating previously improper fillers such as carbon black of significantly higher surface area and lower structure is achieved. do. Dispersion properties of natural rubber masterbatches made according to the methods and apparatus disclosed herein can be demonstrated with reference to well-known MW _sol (weight average) and macro-dispersity properties. In particular, the macro-dispersion level of the masterbatch prepared according to the preferred embodiment is significantly better than that of the masterbatch of approximately equivalent MW _sol prepared using dry chewing. Very surprisingly, the dispersion properties of these preferred embodiments depend very little on the form of the carbon black filler. Other factors affecting the level of dispersion that can be achieved using the methods and apparatus disclosed herein include the concentration of carbon black in the slurry, the total energy introduced into the slurry, the energy introduced during mixing of the fluid stream, and the like. Able to know.

The macro-dispersion properties of the carbon black in the natural rubber masterbatch disclosed herein are significantly better than those of the masterbatch of approximately equivalent MW _sol (weight average) previously known. In some preferred embodiments of the novel elastomeric composites, good carbon black distribution is achieved with approximate MW _sol of natural rubber in the field latex state (eg, approximately 1,000,000), a condition not previously achieved. Dispersion property advantages are achieved by using carbon black with low structure and high surface area, for example DBPA less than 110 cc / 100 g, CTAB between 45 and 65 m 2 / g and DBPA: CTAB ratio less than 1.2, preferably less than 1.0 Of particular importance in the preferred embodiments described above.

Examination process

The following test procedure was used in the following examples and comparative examples.

1. Binding rubber: 0.5 g ± 0.025 g of sample was weighed and placed in 100 ml of toluene in a sealed flask and stored at ambient temperature for about 24 hours. The toluene was then replaced with 100 ml of fresh toluene and the flask was stored for 4 days. The sample was then removed from the solvent and air dried under hood for 24 hours at ambient temperature. The sample was then further dried in a vacuum oven at ambient temperature for 24 hours. The sample was then weighed and the binding rubber calculated from the weight loss data.

2. MW _sol: This disclosure and the MW _sol used in the claims refers to the weight average molecular weight of the sol portion of the natural rubber. Standard GPC techniques for molecular weight measurements were performed as follows.

2.1 Two 10 μm 10 ⁶ μs columns, 10 μm 500 μs columns and 10 μm mixed phase columns (Polymer Laboratories, UK)

2.2 UV detection at 215 nm

2.3 Solvent: Tetrahydrofuran (THF)

2.4 concentration, nominal 2 mg / ml in THF

2.5. Samples were dissolved in THF stabilized with BHT and left for 3 days.

The 2.6 solution was centrifuged to separate any gel and the supernatant was injected into the column.

2.7 Sample Preparation

Samples were prepared to produce sol concentrations ranging from 0.5 to 0.05 weight percent to provide good detector response for accurate measurement of molecular weight distribution. Depending on the filler load, the sample weight is given by:

Sample weight = (100 + filler load (phr) * 20/100 mg ± 2 mg

Adjusted accordingly. Samples were placed in UV protected vials and dissolved for 3 days in 4 ml of stabilized tetrahydrofuran (THF) containing 0.02% butylated hydroxyltoluene (BHT). The supernatant containing the nearly sol portion of the dissolution step was transferred to a Teflon centrifuge tube and centrifuged in an Avanti 30 (Beckman) centrifuge for 60 minutes at 26,000 revolutions / minute (corresponding to a maximum magnetic field strength of 57,500 g). Separated. At this magnetic field strength, many gel phases precipitated gel-free supernatants. This gel-free solution was diluted 1: 5 again with stabilized THF. At this moment, the samples were transferred to GPC vials and placed in Waters 717 Auto-Sampler, Water Corporation, Milford, Massachusetts, prepared for GPC testing.

Molecular Weight Measurement

Next, the weight average molecular weight MW _sol of the sol portion was measured. Baseline was defined using the Valley-to-valley method in 15 and 35 minute time increments using Millennium software (Waters Corporation, Milford, Mass.). This time increase was appropriate for the column set described in 2.1 above with the mobile phase flow rate adjusted to 0.75 ml / min. Once a reasonable baseline is established, the distribution can be measured. Elution time was converted to molecular weight. A polystyrene solution containing a series of molecular weights in a very narrow distribution, prepared from commercial standards (EasiCal: Polymer Laboratories, UK), was prepared. The conversion of polystyrene molecular weight to polyisoprene molecular weight equivalent was based on the conventional assay method of Benoit and colleagues. The hydrodynamic radius was proportional to the result of intrinsic viscosity x molecular weight. After conversion of polystyrene molecular weight to polyisoprene molecular weight equivalent, the assay curve relates to absolute molecular weight versus elution time. Standards were run under the same conditions as the samples and the standards were integrated to assign the appropriate molecular weights for the elution times provided based on the best fit to the standard data. Once the time-based distribution was properly converted to molecular weight, the appropriate molecular weight average was calculated by Watertm Millennium Software.

3. Mooney Viscosity: Standard procedure according to ML (1 + 4) ＠ 100 ° C.

4. Test Sample Curing Conditions: The test pieces were cured at 150 ° C. for the time indicated below.

4.1 Tension Sheet: 20 minutes

4.2 Stability: 23 minutes

4.3 Longitude: 23 minutes

4.4 Heat accumulation: 25 minutes

5. Dispersion: The Cabot Dispersion Chart method was used with the evaluation of 50x optical micrographs (ASTM D2663 method).

6. Stress-strain: Tested according to BS903: A2 and ISO 37.

7. Hardness: Tested according to ISO 48 (1994) (temperature 23 ° C).

8. Stability: Tested according to BS903: A8 (1990), Method A (temperature 23 ° C., 8 mm molded disc test piece).

9. Heat accumulation: tested according to ASTM D623, Method A.

9.1 Start temperature: 23 ° C

9.2 Static load: 10.89 kg (24 lbs)

9.3 stroke: 0.57 cm (0.225 in)

9.4 Frequency: 30 Hz

9.5 30 minutes run.

10. Tan δ: Measured on Rheometrics Model RDS II. The value recorded is the maximum from the strain sweep. Strain sweep at 0 ° C., 30 ° C. and 60 ° C., 1 Hz and 0.1% to 60% strain.

11. Crack Growth Resistance: Measured according to ASTM D3629-94.

Example A

Elastomer masterbatches were prepared according to the present invention. In particular, an elastomeric masterbatch comprising standard natural rubber field latex (Malaysia) was prepared with 52.5 phr of filler consisting of carbon black of industrial grade N234 (Cabot Corporation). The properties of the natural rubber field latex are provided in Table 1 below.

TABLE 1

Natural rubber latex properties

The overall compound composition is shown in Table 2 below, and is a commercial truck tire tread known to have good resistance to conversion during curing.

TABLE 2

Masterbatch Composition

The elastomer masterbatch production apparatus was substantially the same as the apparatus described above with reference to FIGS. 1 and 7. The slurry nozzle tip (see 167 in FIG. 7) was 0.099 cm (0.039 inches) in diameter with a portion having an axial length of 0.508 cm (0.2 inches). The coagulation zone was 0.478 cm (0.188 inch) in diameter and the constant axial length of the constant diameter between the mixing zone and its discharge end was 2.50 cm (0.985 inch). The preparation of the masterbatch is described in more detail below.

1. Carbon Black Slurry Manufacturing

The bag of carbon black was mixed with deionized water in a carbon black slurry tank equipped with a stirrer. The stirrer ruptured the pellets into debris and formed a crude slurry with 12.5% by weight carbon black. During operation, this slurry was continuously pumped into a colloid mill during initial dispersion by an air diaphragm pump. The slurry was then fed to a homogenizer, specifically a model M3 homogenizer (APV Gaulin, Inc.) by a process cavity pump. The finely ground slurry was prepared by a homogenizer. The slurry flow rate from the homogenizer to the mixing zone was adjusted by the homogenizer speed, and the homogenizer acted as a high pressure positive displacement pump. Slurry flow rates were monitored with a Micromotion® mass flow meter. The carbon black slurry was fed to the homogenizer at a pressure in the range of 50 to 100 psig, and the homogenization pressure was adjusted to 4000 psig so that the slurry had a flow rate of 1.86 to 2.00 kg / min (4.1 to 4.4 lb / min) and about 39.62 m / sec ( At a speed of about 130 ft / sec) as a jet into the mixing zone.

2. Latex Delivery

Latex was charged to 378.54 liters (100 gallons) of pressurized feed tank. Antioxidant emulsion was added to the latex prior to loading. An antioxidant consisting of 0.3 phr of trisnonyl phenyl phosphite (TNPP) and 0.4 phr of Santoflex® 134 (alkyl-aryl p-phenylene diamine mixture) was added. Each antioxidant was prepared as a 15 wt% emulsion using 3 parts of potassium oleate per 100 parts of antioxidant with potassium hydroxide to adjust the pH of the fluid to about 10. 3 phr of extender oil was also added. Air pressure (51 psig) was used to transfer the latex from the feed tank to the mixing zone of the coagulation reactor. Latex flow rates ranged from 3.2 to 3.4 lbs / min and about 3.8 ft / sec and were automatically weighed and adjusted with a micromotion® mass flow meter and rubber tube pinch valve. By maintaining an appropriate ratio of latex feed rate to carbon black slurry feed rate, the desired carbon black loading of 52.5 phr was obtained.

3. Carbon black and latex mixed

Latex was intrained into the carbon black slurry to mix the carbon black slurry and latex. During intrain, the carbon black was intimately mixed into the latex and the mixture solidified. A soft wet sponge "worm" was discharged from the coagulation reactor.

4. Dehydration

The wet crumb released from the coagulation reactor was about 79% water. The wet crumb was dewatered with a dehydration extruder (The French Oil Mill Machinery Company, 3.5 inches) at about 5-10% moisture. In the extruder, the wet crumb was compressed and water was removed from the crumb through the perforated barrel of the extruder.

5. Drying and Cooling

The dewatered crumb was dropped into a second extruder where it was again compacted and heated. Water was flowed through the die plate of the extruder when crumb was removed. The product release temperature was about 148.89 ° C. (about 300 ° F.) and the moisture content was about 0.5 to 1 weight percent. The hot dry crumb was quickly cooled to about 37.78 ° C. (about 100 ° F.) by a forced air vibration conveyor (about 20 seconds). The resulting dry crumb was about 66 wt% rubber solids and about 33 wt% carbon black.

Example B

Control masterbatches were prepared by dry chewing. The control used the same composition as Example A (see Table 2 above) except that the natural rubber was SMR 10 rather than latex. This was prepared by preliminary mastication of the rubber in an OOC Banbury mixer (about 3 kg) at 50 rpm using 10 phr of carbon black. Preliminary chewing was performed for up to 800 MJ / m 3 for about 3 minutes.

Comparison of Examples A and B

The masterbatch of Example A and the control masterbatch of Example B were mixed in a two stage mixing operation in an OOC half-bake mixer (about 3 kg). Table 3 below discloses the mixing scheme for the first step. The masterbatch of Example A may appear to follow a modified mixing scheme.

TABLE 3

One step blending plan

In the second step, the cured product listed in Table 4 below was added with an additional mixing cycle of 500 MJ / m 3.

TABLE 4

Addition of hardened material at the final stage

Thus, the half-bump mixing energy for mixing the masterbatch of Example A was about 53% of the half-bump mixing energy required for pre-chewing and mixing of the control material of Example B. Despite the reduced energy input, the material of Example A was found to have a very good macro-dispersity and the molecular weight (weight average) MW _sol of its sol portion was significantly higher than that of the control. These data are summarized in Table 5 below.

TABLE 5

Blending and Curing Data

Additional test results for cured (unaged) Example A and control materials are set forth in Table 6 below.

TABLE 6

Additional test data

Example C

Elastomer masterbatches were prepared according to the present invention. In particular, an elastomeric masterbatch comprising standard natural rubber field latex (Malaysia) was prepared with 55 phr of filler consisting of carbon black from Industrial Grade Regal 660 (Cabot Corporation). Compound compositions (except the least common latex additives) are set forth in Table 7 below.

TABLE 7

Masterbatch Composition

The elastomer masterbatch production apparatus was substantially the same as the apparatus described above with reference to FIGS. 1, 3 and 7. The slurry nozzle tip (see 167 in FIG. 7) was 0.064 cm (0.025 inch) in diameter with a portion having an axial length of 0.508 cm (0.2 inch). The solidification zone (see reference numeral 3 in FIG. 3) has a first diameter of 0.477 cm (0.188 inch) and an axial length of about 2.502 cm (about 0.985 inch), which is part of the mixing head and part of the expander sealed thereto. Portion, a second portion of 0.666 cm (0.675 cm) in diameter and 1.6 inches (4.064 cm) in axial length, a third portion of 0.376 inch (0.955 cm) in diameter and 2.256 inches (5.730 cm) in axial length, and 1.351 cm (diameter) 0.532 inch) and an axial length of 8.103 cm (3.190 inch) of a fourth portion. In addition, there are axially short interconnections between the aforementioned parts. The preparation of the masterbatch is described in more detail below.

1.Manufacture of carbon black slurry :

The bag of carbon black was mixed with deionized water in a carbon black slurry tank equipped with a stirrer. The stirrer broke the pellets into pieces and a crude slurry with 14.9 wt% carbon black was formed. The crude slurry was recycled using a pipeline mill. During operation, this slurry was continuously pumped into a colloid mill during initial dispersion by an air diaphragm pump. The slurry was then fed by a process cavity pump to a homogenizer for pressurization and shear, in particular a microfluidizer model M210 (Microfluidics International Corporation) to produce a finely ground slurry. The flow rate of slurry from the microfluidizer to the mixing zone was controlled by the microfluidizer speed, and the microfluidizer acted as a high pressure positive displacement pump. Slurry flow rates were monitored with a MicroMotion® mass flow meter. The carbon black slurry was fed to the microfluidizer at a pressure in the range of about 130 psig, and the outlet pressure was adjusted to 3000 psig for the accumulator adjusted to 450 psig outlet pressure so that the slurry had a flow rate of 1.77 kg / min (3.9 lb / min). And a jet into the mixing zone at a speed of about 91.44 m / sec (about 300 ft / sec).

2. Latex Delivery

Latex was charged to a tank, specifically a feed tank of 208.2 liters (55 gallons). Antioxidant emulsion was added to the latex prior to filling. An antioxidant consisting of 0.3 phr of trisnonyl phenyl phosphite (TNPP) and 0.4 phr of Santoplex® 134 (alkyl-aryl p-phenylene diamine mixture) was added. Each antioxidant was prepared as a 40 wt% emulsion using 4 parts of potassium oleate per 100 parts of antioxidant with potassium hydroxide to adjust the pH of the fluid to about 10. Peristaltic pumps were used to transfer the latex from the feed tank to the mixing zone of the coagulation reactor. Latex flow rates were 1.45 to 1.54 kg / min (3.2 to 3.3 lbs / min) and about 1.19 m / sec (about 3.9 ft / sec), metered by Endress + Hauser, Greenwood, Indiana It was. By maintaining an appropriate ratio of latex feed rate to carbon black slurry feed rate, the desired carbon black loading 55 phr was obtained.

3. Carbon black and latex mixed

Latex was intrained into the carbon black slurry to mix the carbon black slurry and latex. During intrain, the carbon black was intimately mixed into the latex and the mixture solidified. A soft wet sponge "dignity" was discharged from the coagulation reactor.

4. Dehydration

The wet crumb released from the coagulation reactor was about 78% of water. The wet crumb was dewatered with a dehydration extruder (3.5 inches), The French Oil Mill Machinery Company, about 12-13% moisture. In the extruder, the wet crumb was compressed and water was removed from the crumb through the perforated barrel of the extruder.

5. Drying and Cooling

The dewatered crumb was dropped into a second extruder where it was again compacted and heated. Water flowed through the die plate of the extruder when crumb was removed. The product release temperature was about 137.78 ° C. to 187.78 ° C. (about 280 ° F. to 370 ° F.) and the moisture content was about 0.3 to 4 wt%. The hot dry crumb was quickly cooled to about 37.78 ° C. (about 100 ° F.) by a forced air vibration conveyor (about 20 seconds).

Examples D and F

Two dry mixed control masterbatches were prepared by dry chewing. For control, the same composition as Example C (see Table 7 above) was used except that the natural rubber in Example D was RSS1 NR rather than latex. In Example E the rubber was SMR 10 NR. Each was prepared by premasticating the rubber in a BR half-blow mixer. The rubber of Example D was masticated at 118 rpm for 10 minutes. The rubber of Example E was masticated at 77 rpm for 4 minutes.

Comparison of Examples C, D and E

The masterbatch of Example C and two control masterbatches of Examples D and E were mixed in a BR half-bowl mixer. The mixing scheme is disclosed in Table 8 below.

TABLE 8

Mixed planning

Mixed compositions are provided in Table 9 below.

TABLE 9

Step II Add Cured Product

All three compounds showed good behavior cure with minimal resoftening rate. Despite the reduced energy input, the material of Example C was found to have a very good macro-dispersity and the molecular weight (weight average) MW _sol of its sol portion was significantly higher than the control. These data are summarized in Table 10 below.

TABLE 10

Masterbatch and Compound Properties

Additional Examples and Comparisons

Very preferred elastomeric composites according to the present invention were prepared according to the methods and apparatus disclosed above. In particular, new masterbatch compositions were formed from natural rubber latex and carbon black having significantly better macro-dispersion levels and / or natural rubber molecular weights than previously found in known compositions formed with the same or similar starting materials. 8 shows the surface area and structure of various carbon black fillers used in preferred masterbatch compositions, in particular the CTAB surface area expressed in square meters per gram of carbon black according to ASTM D3765-85 and DBP per 100 grams of carbon black according to ASTM D2414. The dibutyl phthalate adsorption amount (DBPA) value expressed in cubic centimeters of is shown. In Figure 8 it can be seen divided into three different regions of carbon black. Zone I comprises carbon blacks having a low structure and high surface area, which are difficult to disperse in natural rubber and other elastomers using conventional dry mixing techniques. Therefore, the carbon black in the region I is not used for commercial use as widely as other carbon blacks. Masterbatches and cured elastomeric compositions made of carbon black in zone I using conventional dry mixing techniques had poor macro-dispersity and typically low MW _sol . Carbon black in zone II had a structure higher than that in zone I. Typically, when injected into these extended dry blends where the MW _sol of natural rubber is significantly lowered, they are reasonably well dispersed in natural rubber for vehicle tire products and the like. The carbon black in region III of FIG. 8 had a lower surface area compared to their structure. Thus, they were allowed to disperse into the natural rubber through dry mixing but undesirably lowered the MW _sol . The dispersion of the carbon black in all three regions of FIG. 8, in particular the macro-dispersity, has been significantly improved in the elastomer composites disclosed herein and can achieve a significantly higher MW _sol of natural rubber according to a preferred embodiment.

Control Samples 1-443

A control sample of the masterbatch was prepared by dry mixing according to the following procedure for comparison with respect to the elastomeric composite of the present invention.

1. Authoring of natural rubber

To prepare dry masterbatches with a wide range of molecular weights, commercially available natural rubbers (RSS1, SMR CV and SMR 10) bales were pre-wound in a BR halfburi mixer using the following conditions (fill factor: 0.75).

TABLE 11

Natural rubber chewing conditions

2. Mixing of Carbon Black with Pre-Branched Natural Rubber

To prepare a natural rubber dry masterbatch having different levels of macro-dispersion properties, the following mixing procedure was used in a BR half-binder mixer. The filling factor was 0.70. The masterbatch components and mixing procedure are listed in Table 12 below.

TABLE 12

Natural Rubber Dry Masterbatch Composition

Different levels of macro-dispersions were prepared by dry mixing samples of pre-masticated natural rubbers of M1 to M4 for different mixing times, as shown in Table 13 below. For example, in Table 13 sample code M2D1 represents a control sample of pre-masticated natural rubber M2 (see Table 11 above) mixed for 10 minutes according to the composition of Table 12.

TABLE 13

Mixing time

3. Final Mix of Natural Rubber Masterbatch Control Samples

To assess compound performance, additional ingredients were added to the dry masticated natural rubber masterbatch control samples of Table 3 according to the compositions shown in Table 14.

TABLE 14

Additional Ingredients for Final Mix

Compounds were cured according to standard curing techniques, typically at 150 ° C. until 10-30 minutes, at least until they were fully cured. In this regard, all samples of the elastomeric composites of the present invention prepared and cured in the manner described below (see examples of preferred embodiments), as well as all control samples, have the same or substantially the same final mixing procedure comprising the compositions provided in Table 14 above. And compound and performance characteristics were tested.

The sol molecular weight MW _sol and macro-dispersity D (%) of Control Samples _1-443 are set forth in Tables 15-23 below. Samples were sorted in the table according to the choice of carbon black. Within the table provided, samples were sorted by selection of natural rubber and carbon black loading and oil loading. Table headings show this information according to standard names. Thus, for example, the title “N330 / 55 phr / 0” in Table 15 refers to 55 phr of N330 carbon black without oil. The subtitle in the table shows the selection of natural rubber. In particular, Control Samples 1-450 appear to be made of standard grade natural rubber RSS1, SMR CV and SMR 10. Technical descriptions of these natural rubbers are widely available, such as from Rubber World Magazine's Blue Book, Lippincott and Peto, Inc., Akron, Ohio, USA. The molecular weight MW _sol of the natural rubber before any pretreatment (M1) and after various amounts of pretreatment (M2-M4) is also shown in Tables _15-23 below.

TABLE 15

TABLE 16

TABLE 17

Table 18a

Table 18b

TABLE 19

TABLE 20

Table 21a

Table 21b

Table 22a

Table 22b

TABLE 23a

TABLE 23b

Example for Preferred Aspects

Additional samples of the elastomeric composites according to the invention were prepared. Specifically, a series of natural rubber elastomer composites 1-32 according to the present invention were prepared using the general apparatus and procedure according to Example A above. The elastomeric composite included a Malaysian natural rubber field latex with the properties shown in Table 24 below. The elastomeric composite further included carbon black having morphological properties (structure and surface area) of regions I, II or III of FIG. 8, respectively. Specifically, as carbon black, Regal (Regal) 660, N234, N326, N110, Regal (registered trademark) 250, N330, Black Pearl (registered trademark) 800, Sterling (registration) 6740 and N351. Carbon black loading was in the range of 30 to 75 phr, and extender oil loading was in the amount of 0 to 20 phr. Table 25 shows the details of preparation of Elastomer Composite Sample Nos.

As mentioned above, the devices and procedures used to prepare the elastomeric composites 1-32 are generally in accordance with Example A, which includes the additives for the masterbatch formulation shown in Table 2. The devices and procedures used for elastomeric composites 1-32 are described in more detail below.

1. Device

Samples 1-32 of the present invention were prepared using a masterbatch manufacturing apparatus substantially consistent with the apparatus of the present invention described above with reference to FIGS. For each of the samples 1-32, Table 25 shows the diameter of the slurry nozzle tip (see 167 in FIG. 7) and the length of the portion (see 168 in FIG. 7). The coagulation zone of the device has four zones that gradually increase in diameter from the mixing zone to the discharge end. Table 25 lists the diameters and axial lengths of each of the four zones (some of which are present in the mixing head and some of which are in the dilators sealed thereto). Between the zones there are axially short fitting internal connections.

2. Carbon black slurry manufacturing

In a carbon black slurry tank equipped with a stirrer, the carbon black bag was mixed with deionized water. The pellet was broken into pieces by a stirrer to form a crude carbon black slurry. Table 25 shows the carbon black concentration (wt%) in the carbon black slurry for each sample. During the run, slurry was continuously injected into the initial dispersion grinder using an air diaphragm pump. The slurry was then injected into a colloid mill using an air diaphragm pump, followed by a homogenizer, in particular a microfluidizer model M210 (manufactured by Microfluidics International Corporation) via a progressive pore pump. A finely ground slurry was obtained by the microfluidizer. The microfluidizer pressure and the slurry flow rate from the microfluidizer to the mixing zone were set using the microfluidizer acting as a high pressure constant displacement pump. The slurry flow rate was monitored with a Micromotion® mass flow meter. The pressure at which carbon black sludge is injected into the homogenizer and the homogenizer outlet pressure (all pressures are in psig) are listed in Table 25 for each sample. Carbon black slurry was injected into the scaler from the homogenizer to reduce random fluctuations in slurry pressure at the slurry nozzle tip of the mixing zone. Table 25 lists the slurry nozzle tip pressures and flow rates for which the slurry was injected into the mixing zone for each sample.

3. Latex carrying

Latex was charged to a 208 liter (55 gallon) feed drum. The antioxidant emulsion was then added to the latex and mixed before charging. Antioxidants including trisnonyl phenyl phosphite (TNPP) and Santoflex® 134 (alkylaryl p-phenylene diamine mixture) were added in the amounts shown in Table 25. Each antioxidant was prepared as 40% by weight emulsion using 4 parts potassium oleate per 100 parts antioxidant with potassium hydroxide adjusting the pH of the emulsion to about 10. If desired, extender oil was added in the amounts shown in Table 25. Peristaltic pumps were used to transfer the latex from the feed drum of the coagulation reactor to the mixing zone. Latex flow rates and rates are shown in Table 25. Latex fluidity was automatically metered with an Endress + Hauser mass flow meter. The ratio of the latex feed rate to the carbon black slurry feed rate was properly maintained to obtain the desired carbon black loading.

4. Carbon Black and Latex Blend

Latex was intrained into the carbon black slurry to mix the carbon black slurry and latex. In the intrain, carbon black was intimately mixed with the coagulated latex and the mixture. The coagulum of the soft, wet sponge “warm” was discharged from the coagulation reactor.

5. Dehydration

Table 25 shows the water content of the wet crumbs released from the coagulation reactor. The wet crumb was dewatered using a dewatering extruder (The French Oil Mill Machinery Company; diameter: 8.89 cm (3.5 in)). In the extruder, the wet crumb was compressed, water was squeezed out of the crumb and removed through the perforated barrel of the extruder. The water content of the final crumb is shown in Table 25 for each sample of the present invention.

6. Drying and Cooling

The dewatered crumb was dropped with a second extruder and again compressed and heated. Water came out when the crumb was removed through the die plate of the extruder. Product discharge temperature and water content are shown in Table 25. The hot dried crumb was cooled at high speed (about 20 seconds) to about 37.78 ° C. (100 ° F.) by a forced air vibration conveyor.

TABLE 24

Natural rubber latex properties

Table 25a

Details on Preparation of Samples of the Invention

Table 25b

Details on Preparation of Samples of the Invention

TABLE 25c

Details on Preparation of Samples of the Invention

Table 25d

Details on Preparation of Samples of the Invention

It should be noted that Samples 2 and 3 are produced with little exit pressure applied at the microfluidizer outlet, etc. to measure macro-dispersity under reverse processing conditions.

The good carbon black dispersion in the obtained masterbatch is demonstrated by its macro-dispersion properties and the molecular weight MW _sol of the sol portion. Table 26 below shows the MW _sol and macro-dispersity values for Samples 1-32 of the present invention, along with the carbon black and oil (if present) used in each sample. Carbon black loading and oil loading are shown in phr values in Table 26.

TABLE 26

Sol Molecular Weight and Undispersed Area of Samples of the Invention

Results for all samples of the present invention with a carbon black loading of 55 phr are shown in FIG. 9 with the macro-dispersity and MW _sol values for the corresponding series of natural rubber control samples prepared by dry mixing. Shown in the log plot. One or more data points for the sample of the invention comprising each carbon black at a loading of 55 phr are shown in FIG. 9 with all control samples having a carbon black loading of 55 phr. (FIG. 9 also shows control samples 401-412 using 33 phr of N 351 carbon black and 20 parts of extender oil.) Table 26 and FIG. 9 show that the samples of the present invention have excellent macro-dispersity. have. Specifically, samples of the present invention generally have D (%) values of less than 0.2% at MW _sol values of _greater than 0.85 × 10 ⁶ , while control samples _exhibit such good macro-dispersity at any MW _sol . Can not get In other words, the data shown in FIG. 9 shows that the macro-dispersion properties of the novel elastomeric composites over a wide range of MW _sol values are significantly superior to the macro-dispersion properties obtainable using similar components in known mixing methods. Shows. The symbols used for the various data points shown in FIG. 9 and the symbols used in FIGS. 10-25 discussed later are described in the legend below.

<Description of Drawing>

9 relates to the dispersion characteristics and MW _sol of the NR masterbatch.

10 relates to the dispersion characteristics and MW _sol of the NR masterbatch (region I).

11 relates to the dispersion characteristics and the MW _sol of the NR masterbatch (region II).

12 relates to the dispersion characteristics and the MW _sol of the NR masterbatch (region III).

FIG. 13 relates to the dispersion characteristics and MW _sol of the NR masterbatch (N330 carbon black, 55 phr).

FIG. 14 relates to the dispersion characteristics and MW _sol of the NR masterbatch (Regal 250 carbon black).

15 relates to the dispersion characteristics and MW _sol of NR masterbatch (Black Pearl 800 carbon black, 55 phr).

FIG. 16 relates to the dispersion characteristics and MW _sol of NR masterbatch (N325 carbon black, 55 phr).

FIG. 17 relates to the dispersion characteristics and MW _sol of the NR masterbatch (Regal 660 carbon black).

18 relates to the dispersion characteristics and MW _sol of the NR masterbatch (N234 carbon black).

19 relates to the dispersion characteristics and MW _sol of NR masterbatch (N110 carbon black, 55 phr).

20 relates to the dispersion characteristics and MW _sol of NR masterbatch (N351 carbon black, 33 phr).

Figure 21 relates to the dispersion characteristics and MW _sol of the NR masterbatch (stering 6740 carbon black, 55 phr).

FIG. 22 relates to the effect of MW _sol on crack growth rate (NR compound containing 55 phr loading of N234 carbon black).

FIG. 23 relates to the effect of MW _sol on crack growth rate (NR compound containing 55 phr loading of N326 carbon black).

FIG. 24 relates to the effect of MW _sol on crack growth rate (NR compound containing 55 phr loading of Regal 660 carbon black).

FIG. 25 relates to the maximum tangent (δ) δ (strain sweep at 60 C) of NR compounds containing N234 black at various loadings.

FIG. 30 relates to the macro-dispersion properties of the NR masterbatch containing the dual phase (carbon black / silica) aggregates and the MW of the sol portion.

FIG. 31 relates to the macro-dispersion properties of the NR masterbatch containing blends of carbon black and silica and the MW of the sol portion.

Macro-dispersion values for the inventive elastomeric composites shown in FIG. 9 are described by the following equation:

[Equation 1]

[Equation 2]

From the discussion above, it will be appreciated that the macro-dispersity D (%) in Equation 1 above is the% undispersed area measured for defects greater than 10 microns. It can be seen from FIG. 9 that D (%) corresponding to 0.2% is the critical point of the macro-dispersion properties of all carbon blacks in areas I, II and III of the natural rubber dry masterbatch. That is, as described in Equation 1 above, even after the MW _sol is sufficiently mixed so as to lower it to less than 0.45 × 10 ⁶ , none of the dry masticated masterbatches _achieves 0.2% macro-dispersion property in any MW _sol . I couldn't. When the MW _sol of the dry master batch control sample shown in FIG. 9 is between 0.45 × 10 ⁶ and 1.1 × 10 ⁶ , the dispersing characteristics are inferior, whereas the dispersing characteristics of the sample of the present invention having the MW _sol in the above range are in an excellent state. to be. None of the preferred embodiments shown in FIG. 9, where the MW _sol is between 0.45 × 10 ⁶ and 1.1 × 10 ⁶ , exceeds the preferred macro-dispersity limit 0.2%. In this regard, the data points of the preferred embodiment shown on the X axis (i.e. 0.1% D (%)) of FIG. 9 (and other figures described below) are 0.1% or better (i.e., lower) D (%). Will be understood to have a macro-dispersity of the numerical value).

Zone I Carbon Black Sample

Samples of the invention comprising carbon black having the morphological properties (ie, structure and surface area) of region I of FIG. 8 and corresponding control samples prepared as such with region I carbon black are semi-logs of FIG. Compare on the plot. Specifically, FIG. 10 shows carbon black Regal®, N326, Regal® 250, N330, and Black Pearl® 800 and 0 phr to 20 phr in loads ranging from 30 phr to 75 phr. Macro-dispersity values and MW _sol values of the samples of the invention and corresponding control samples containing an amount of extender oil of. Excellent carbon black dispersion for all samples of the present invention, showing a preferred embodiment of the elastomeric composite according to the present disclosure, is identified from FIG. 10. All advantageous samples of the present invention were below line 101 of FIG. 10, while all control samples with inferior dispersion were above line 101 of FIG. In fact, the preferred embodiment shown in FIG. 10 is the most difficult to disperse, even when including carbon black from region I, corresponding to less than 0.3% D (%) value. Most preferred embodiments have D (%) values that do not exceed 0.2% even with favorable MW _sol values of _greater than 0.7 × 10 ⁶ . The data shown in FIG. 10 shows that the macro-dispersion properties of the novel elastomeric composites disclosed herein that include region I carbon black over a wide range of MW _sol values can be obtained using similar components by conventional dry chewing mixing methods. It is clearly shown to be significantly superior to. Macro-dispersion values for the inventive elastomeric composites shown in FIG. 10 are described by the following equation:

[Equation 3]

[Equation 4]

It will be appreciated that D (%) is the% undispersed area measured for defects greater than 10 microns and 1% is the critical point of the macro-dispersion properties of all carbon blacks in zone I of the natural rubber dry masterbatch. That is, as described in Equation 3 above, even after sufficient dry mixing to reduce the MW _so.l to less than 0.7 × 10 ⁶ , _none of the dry _{chewed masterbatches} is 1.0% or better in any MW _sol . No dispersion properties were obtained. When the MW _sol of the dry masterbatch control sample shown in FIG. 10 is between 0.7 × 10 ⁶ and 1.1 × 10 ⁶ , the dispersion characteristics are inferior. On the other hand, the dispersion characteristics of the sample of the present invention having the MW _sol in the above range is in an excellent state. The preferred embodiment shown in FIG. 10, with MW _sol between 0.7 × 10 ⁶ and 1.1 × 10 ⁶ , falls well below the preferred macro-dispersity limit of 0.2%. It can be seen that the elastomeric composites of the invention comprising carbon black in region I provide a balance between macro-dispersion properties and MW _sol that could not be achieved previously.

Zone II Carbon Black Sample

A sample of the invention comprising carbon black having the morphological characteristics (ie, structure and surface area) of region II of FIG. 8 and a corresponding control sample prepared as above with region II carbon black are semi-logs of FIG. Compare on the plot. Specifically, FIG. 11 is a macro-dispersity diagram of a sample of the present invention and a corresponding control sample comprising loadings of carbon black N234 and N110 and loadings of extender oil in the range of 40 phr to 70 phr, and 0 phr to 10 phr. The numerical value and MW _sol value are shown. Excellent carbon black dispersion for all samples of the present invention, showing a preferred embodiment of the elastomeric composite according to the present disclosure, is identified from FIG. 11. Advantageous samples of the present invention were below line 111 of FIG. 11, while all control samples with inferior dispersion were above line 111. In short, the preferred embodiment shown in FIG. 11 comprising the carbon black in zone II corresponds to less than 0.3% D (%) value. The most preferred embodiment has a D (%) value that does not exceed 0.2% at any MW _sol value. The data shown in FIG. 11 shows that the macro-dispersion properties of the novel elastomeric composites disclosed herein comprising region II carbon black over a wide range of MW _sol values can be obtained using similar components by conventional dry chewing mixing methods. It is clearly shown to be significantly superior to. The macro-dispersion values for the elastomeric composites of the invention shown in FIG. 11 are described by the following equation:

[Equation 5]

[Equation 6]

It will be appreciated that D (%) of 0.30 is the critical point of the macro-dispersion properties of all carbon blacks in zone II of the natural rubber masterbatch according to the invention, and 0.35 x 10 ⁶ is the MW _sol threshold. That is, as described in Equation 5 above, even after the MW _sol is sufficiently dry mixed so as to lower it to less than 0.35 × 10 ⁶ , none of the dry masterbatch obtains 0.30% or better macro-dispersion property in any MW _sol . I couldn't. When the MW _sol of the dry masterbatch control sample shown in FIG. 11 is between 0.35 × 10 ⁶ and 1.1 × 10 ⁶ , the dispersion characteristics are inferior. On the other hand, the dispersion characteristics of the sample of the present invention having the MW _sol in the above range is in an excellent state. The preferred embodiment shown in FIG. 11, with MW _so.l between 3.5 × 10 ⁶ and 1.1 × 10 ⁶ , _falls well below the preferred macro-dispersity limit of 0.2%. It can be seen that the elastomeric composites of the present invention comprising carbon black in region II provide a balance between macro-dispersion properties and MW _sol that could not be achieved previously.

Zone III Carbon Black Sample

A sample of the invention comprising carbon black having the morphological characteristics (ie, structure and surface area) of region III of FIG. 8 and a corresponding control sample prepared as above with region III carbon black are semi-logs of FIG. Compare on the plot. Specifically, FIG. 12 shows macro-dispersion of samples of the invention and corresponding control samples comprising loadings of carbon black N351 in the range of 30 phr to 70 phr and sterling 6740 and loading extender oil in the range of 0 phr to 20 phr. Figures and MW _sol figures are shown. Excellent carbon black dispersion for all samples of the present invention showing preferred embodiments of the elastomeric composites according to the present disclosure is identified from FIG. 12. All of the advantageous samples of the present invention were below line 121 of FIG. 12, while all control samples with inferior dispersion were above line 121. In short, the preferred embodiment shown in FIG. 12 comprising carbon black in zone III advantageously corresponds to a value of less than 0.1% of the D (%) even in MW _sol of 0.3 × 10 ⁶ , even in excess of 0.7 × 10 ⁶ in the wick. . The data shown in FIG. 12 shows that the macro-dispersion properties of the novel elastomeric composites disclosed herein comprising region III carbon black over a wide range of MW _sol values can be obtained using similar components by conventional dry chewing mixing methods. It is clearly shown to be significantly superior to. Macro-dispersion values for the elastomeric composites of the invention shown in FIG. 12 are described by the following equation:

[Equation 7]

[Equation 8]

It will be appreciated that 0.1% D (%) is the critical point of the macro-dispersion properties of all carbon blacks in zone III of the natural rubber masterbatch according to the invention, and 0.3 x 10 ⁶ is the MW _sol threshold. That is, as described in Equation 7 above, even after sufficiently dry mixing the MW _sol to be lower than 0.35 × 10 ⁶ , none of the dry masterbatch obtained 0.1% macro-dispersion property in any MW _sol . . When the MW _sol of the dry masterbatch control sample shown in FIG. 12 is between 0.30 × 10 ⁶ and 1.1 × 10 ⁶ , the dispersion characteristics are inferior. On the other hand, the dispersion characteristic of the sample of this invention which has MW _sol of the said range is an excellent state. The preferred embodiment shown in FIG. 12 with MW _sol between 0.30 × 10 ⁶ and 1.1 × 10 ⁶ is well below the preferred macro-dispersity limit of 0.2% and is actually below the D (%) value of 0.1%. It can be seen that the elastomeric composites of the present invention comprising carbon black in region III provide a balance between macro-dispersion properties and MW _sol that could not be achieved previously.

Additional Sample Comparison

As shown in Figures 8-12 above, the macro-dispersion values for the sample of the present invention are shown graphically in the semi-log plots of Figures 13-21 as a function of MW _sol values. More specifically, in Figures 13-21, all of the samples of the present invention comprising specific carbon blacks (limited to samples of specific carbon black loadings, when so designated), together with a corresponding control sample, have a single semi-log Shown together on the plot. (See the legend above providing reference signs of the inventive samples and controls included in each figure.) That is, FIG. 13 shows the dispersion properties and MW of the inventive and control samples described above comprising 55 phr N 330 carbon black. _sol . The data shown in FIG. 13 clearly shows that the macro-dispersion properties of the novel elastomeric composites of the invention comprising N330 carbon black over a wide range of MW _sol values are significantly superior to those of the control sample. The macro-dispersion values for the elastomer composite of the present invention comprising N330 carbon black, shown in FIG. 13, are described by the following equation:

[Equation 9]

[Equation 10]

Even after sufficient dry mixing to reduce the MW _sol to less than 0.6 × 10 ⁶ , none of the dry chewable masterbatches achieved a 1.0% macro-dispersion property in any MW _sol (see Equation 9 above). In the control sample containing 55 phr N330 carbon black with MW _sol maintained between 0.6 x 10 ⁶ and 1.1 x 10 ⁶ , the D (%) value is higher. For example, the undispersed area exceeds 4%.

FIG. 14 shows the dispersion characteristics and MW _sol of the present invention and control sample comprising Regal (R) 250 carbon black. Selected invention and control samples shown in FIG. 14 included oil as described above. The data shown in FIG. 14 clearly shows that the macro-dispersion properties of the novel elastomeric composites of the present invention comprising Regal® 250 carbon black over a wide range of MW _sol values are significantly superior to those of the control sample. As shown in FIG. 14, the macro-dispersity values for the elastomer composites of the present invention comprising Regal® 250 carbon black are described by the following equation.

<Equation 9>

<Equation 10>

Even after sufficiently dry mixing the MW _sol to drop below 0.6 × 10 ⁶ , none of the control samples achieved 1.0% or better macro-dispersion properties in any MW _sol . On the other hand, the elastomer composites of the present invention comprising Regal® 250 carbon black having an MW _{sol greater} than 0.6 × 10 ⁶ have an excellent macro-dispersity, for example less than 0.2% D (%). The mixing and performance characteristics of the inventive and control samples shown in FIG. 14, including Regal® 250 carbon black, are listed in Table 27 below. As shown by the very low crack growth rate values of 0.92 cm / million cycles, it can be seen that Sample 4 of the present invention has particularly good resistance to crack growth. In short, the sample of the present invention is very superior to the corresponding control sample. As discussed above, this is presumably due to the better MW _sol and macro-dispersity of the carbon black in the sample of the present invention.

TABLE 27

Composite Properties of NR Compounds Containing Regal 250 Carbon Black at 55 phr Loading

FIG. 15 shows the dispersion characteristics and MW _sol of the present invention and control sample, including Black Pearl (R) 800 carbon black at 55 phr loading. The data shown in FIG. 15 clearly shows that the macro-dispersion properties of the novel elastomeric composites of the invention comprising Black Pearl® 800 carbon black are significantly superior to those of the control sample. As shown in FIG. 15, the macro-dispersity values for the elastomer composites of the present invention comprising Black Pearl (R) 800 carbon black are described by the following equation.

[Equation 11]

[Equation 12]

Even after sufficiently dry mixing the MW _sol was lowered to less than 0.65 × 10 ⁶ , none of the control samples achieved 1.0% or better macro-dispersion properties in any MW _sol . In contrast, the elastomer composites of the present invention comprising Black Pearl® 800 carbon black having an MW _{sol greater} than 0.65 × 10 ⁶ have a good macro-dispersity, for example less than 0.2% D (%). The mixing and performance characteristics of the present invention and control samples shown in FIG. 15 comprising Black Pearl® 800 carbon black are listed in Table 28 below. As indicated by the very low crack growth rate values of 0.27 cm / million cycles, it can be seen that Sample 8 of the present invention has particularly good resistance to crack growth. In short, the sample of the present invention is much better than the corresponding control sample. As discussed above, this is presumably due to the better MW _sol and macro-dispersity of the carbon black in the sample of the present invention.

TABLE 28

Complex Properties of NR Compounds Containing 55 Pearl Loading of Black Pearl 800 Carbon Black

FIG. 16 shows the dispersion characteristics and MW _sol of the present invention and control sample including N326 carbon black at 55 phr loading. The data shown in FIG. 16 clearly shows that the macro-dispersion properties of the novel elastomeric composites of the invention comprising N326 carbon black are significantly superior to those of the control sample. As shown in FIG. 16, the macro-dispersity values for the elastomer composite of the present invention comprising N326 carbon black are described by the following equation.

[Equation 13]

[Equation 14]

Even after sufficiently dry mixing the MW _sol to lower to less than 0.7 × 10 ⁶ , none of the control samples achieved 1.0% or better macro-dispersion properties in any MW _sol . In contrast, the elastomer composites of the present invention comprising N326 carbon black with MW _sol greater than 0.7 × 10 ⁶ have a good macro-dispersity, for example, D (%) of less than 0.2%. The composite and performance characteristics of the present invention and control sample shown in FIG. 16 comprising N326 carbon black are listed in Table 29 below. As shown by the very low crack growth rate values of 0.77 cm / million cycles, it can be seen that Sample 9 of the present invention has particularly good resistance to crack growth. In short, the sample of the present invention is very superior to the corresponding control sample. As discussed above, this is presumably due to the better MW _sol and macro-dispersity of the carbon black in the sample of the present invention.

TABLE 29

Composite Properties of NR Compounds Containing N326 Carbon Black at 55 phr Loading

FIG. 17 shows the dispersion characteristics and MW _sol of the present invention and control sample comprising Regal® carbon black. Selected present and control samples shown in FIG. 17 included oil as described above. The data shown in FIG. 17 clearly shows that the macro-dispersion properties of the novel elastomeric composites of the invention comprising Regal® 660 carbon black over a wide range of MW _sol values are significantly superior to those of the control sample. As shown in FIG. 17, the macro-dispersity values for the elastomer composites of the invention comprising Regal® 660 carbon black are described by the following equation.

[Equation 15]

[Equation 16]

Even after the MW _sol was sufficiently mixed to lower below 0.6 × 10 ⁶ , none of the control samples achieved 1.0% or better macro-dispersion properties in any MW _sol . In contrast, the elastomer composites of the present invention comprising Regal® 660 carbon black having an MW _{sol greater} than 0.6 × 10 ⁶ have a good macro-dispersity, for example less than 0.2% D (%). The composite properties and performance characteristics of the sample 10 of the present invention and various control samples shown in FIG. 17, including Regal® 660 carbon black, are listed in Table 30 below. As shown by very low crack growth rate values of only 0.69 cm / million cycles, it can be seen that Sample 10 of the present invention has particularly good resistance to crack growth. In short, the sample of the present invention is very superior to the corresponding control sample. As discussed above, this is presumably due to the better MW _sol and macro-dispersity of the carbon black in the sample of the present invention.

TABLE 30

Complex Properties of NR Compounds Containing Regal 660 Carbon Black at 55 phr Loading

18 shows the dispersion characteristics and MW _sol of the present invention and control sample described above comprising N234 carbon black. Selected invention and control samples shown in FIG. 18 include oil as described above. The data shown in FIG. 18 shows that the macro-dispersion properties of the novel elastomer composites of the present invention comprising N234 carbon black over a wide range of MW _sol values are significantly better than control samples. The macro-dispersity values of the elastomer composites of the present invention comprising N234 carbon black as shown in FIG. 18 are described by the following equation:

[Equation 17]

Equation 18

Even after sufficiently dry mixing the MW _sol to less than 0.35 × 10 ⁶ , none of the control samples obtained 0.3% or better macro-dispersion properties in any MW _sol . On the other hand, the elastomer composite of the present invention containing N234 carbon black and having an MW _sol greater than 0.35 × 10 ⁶ has excellent macro-dispersity such as D (%) of 0.3% or less or 0.2% or less. The composite and performance characteristics for Sample 14 of the present invention and various control samples, shown in FIG. 18 comprising N234 carbon black, are listed in Table 31 below. It can be seen that Sample 14 of the present invention is excellent in resistance to crack growth, as shown by the crack growth rate value being only 2.08 cm / million cycles.

Table 31

Complex Properties of NR Compounds Containing N234 Carbon Black at 55 phr Loading

FIG. 19 shows the dispersion characteristics and MW _sol of the invention and control samples described above comprising N110 carbon black at a 55 phr loading. The data shown in FIG. 19 shows that the macro-dispersion properties of the novel elastomer composites of the present invention comprising N110 carbon black over a wide range of MW _sol values are significantly better than the control samples. Macro-dispersity values of the inventive elastomeric composites comprising N110 carbon black as shown in FIG. 19 are described by the following equation:

[Equation 19]

[Equation 20]

Even after sufficiently dry mixing the MW _sol to less than 0.35 × 10 ⁶ , none of the control samples achieved a macro-dispersion characteristic of 0.5% in any MW _sol . On the other hand, the elastomer composite of the present invention containing N110 carbon black and MW _{sol greater} than 0.35 × 10 ⁶ has excellent macro-dispersity such as D (%) of less than 0.2%.

FIG. 20 shows the dispersion characteristics and MW _sol of Sample 22 and the control sample of the present invention described above comprising N351 carbon black at 33 phr loading. The data shown in FIG. 20 shows that the macro-dispersion properties of the novel elastomeric composites of the invention comprising N351 carbon black over a wide range of MW _sol values are significantly better than control samples. The macro-dispersity values of the elastomer composites of the present invention comprising N351 carbon black as shown in FIG. 20 are described by the following equation:

[Equation 21]

[Equation 22]

Even after sufficiently dry mixing the MW _sol to less than 0.35 × 10 ⁶ , none of the control samples obtained 1.0% of the macro-dispersion properties in any of the MW _sol . On the other hand, the elastomer composite of the present invention containing N351 carbon black and having an MW _sol greater than 0.35 × 10 ⁶ has excellent macro-dispersity such as D (%) of less than 0.2%.

FIG. 21 shows the dispersion characteristics and MW _sol of Sample 23 and control samples of the present invention described above comprising Sterling® 6740 carbon black at 55 phr loading. The data shown in FIG. 21 shows that the macro-dispersion properties of the novel elastomer composites of the present invention comprising Sterling® 6740 carbon black over a wide range of MW _sol values are significantly better than the comparative samples. The macro-dispersity values of the elastomeric composites of the present invention comprising Sterling® 6740 carbon black as shown in FIG. 21 are described by the following equation.

[Equation 23]

[Equation 24]

Even after sufficiently dry mixing the MW _sol to less than 0.3 × 10 ⁶ , none of the control samples achieved a macro-dispersion of 0.1% or 0.2% in any MW _sol . In contrast, the elastomeric composites of the present invention comprising Sterling® 6740 carbon black and having an MW _{sol greater} than 0.3 × 10 ⁶ have good macro-dispersity, such as D (%) of less than 0.2%, even less than 0.1%. . The compound and performance characteristics of the sample 23 and the control sample of the present invention shown in FIG. 21 comprising Sterling® 6740 carbon black are listed in Table 32 below. It can be seen that Sample 14 of the present invention is excellent in resistance to crack growth, as shown by the crack growth rate being only 0.91 cm / million cycles. In practice, the samples of the invention are much better than the corresponding control samples. It is believed that this is mainly due to the better macro-dispersity of MW _sol and carbon black in the sample of the present invention as discussed above.

Table 32

NR composite properties containing Sterling 6740 carbon black at 55 phr load

Additional Examples: Cured Samples

Multiple masterbatch samples described above, including selected inventive samples and corresponding control samples, were cured and tested. Specifically, the final compounds were prepared by mixing the samples according to step II above in Table 8 using the formulations in Table 9. The final compound in each case was then cured in the mold using standard techniques until substantially complete curing was achieved at about 150 ° C. The performance characteristics of the cured samples were determined by measuring each crack growth rate according to the measurement technique described above using a rotating flexing machine according to ASTM D3629-94. Rotary bends used to measure crack growth are commercially known and well known. For example, the Proceedings of the International Rubber Conference, 1995, Kobe, Japan, Paper 27A-6, pp. 472-475. Compounds were tested at 100 ° C. and flexion angle 45 ^° . It is generally believed to those skilled in the art that the crack growth rate of the compound is influenced by the molecular weight of the natural rubber and the dispersion properties of the carbon black, ie the MW _sol and D (%) values of the compound. Higher MW _sol and lower D (%) correlate significantly with reduced crack growth rate. Crack growth rates and other information for Samples 9, 10, and 16 of the present invention are listed in Table 33 below. Corresponding test results for the corresponding control samples are sorted by selection of carbon black and shown in Table 34 below. In addition, tangent δ _max at 60 ° C. was measured for Samples 24-32 and the corresponding control sample of the present invention. The tan δ _max values at 60 ° C. for the samples of the present invention are listed in Table 35 below. The corresponding test results for the control sample are listed in Table 36 below.

Control Samples 444-450 shown in Table 36 were prepared according to the method described above for Control Sample Code M2D1 using RSS1 natural rubber. All carbon black N234 was used with 5 phr extender oil at the loading levels (phr) shown in Table 36.

Table 33

Crack Growth Rate of Samples of the Invention

Table 34

Crack Growth Rate of Control Sample

Table 35

Tan δ at 60 ° C. for samples of the invention

TABLE 36

Tan δ at 60 ° C. for the control sample

From the comparison of Tables 33 and 34, it can be seen that advantageously lower crack growth rates are achieved by the samples of the present invention compared to the control samples. Lower crack growth rates correlate with relevant properties for many applications, including good durability and tire applications. It can also be seen from the comparison of Tables 35 and 36 that better tan δ _max values, lower than the control sample values, are achieved by the samples of the present invention. Thus, improved performance for many product applications, including, for example, tire applications requiring low hysteresis for corresponding low rolling resistance, is achieved by the samples of the present invention.

Advantageous performance characteristics of the elastomeric composites of the present invention are exemplified by the crack growth rate of Sample 16 of the present invention comprising N234 carbon black and the corresponding test results of Control Samples 273-288 graphed in FIG. 22. . Specifically, FIG. 22 clearly shows the relationship between MW _sol and crack growth rate for the control sample, and the beneficial effect of good macro-dispersity on the elastomer composite of the present invention. It should be understood that the MW _sol values shown in FIGS. 22-24 and Tables 33-36 are for the masterbatch material prior to curing. It is understood that the molecular weight of the cured material is significantly related to the MW _sol value of the uncured masterbatch. The crack growth rate of the control sample on the MW _sol range of about 0.25 × 10 ⁶ to 0.6 × 10 ⁶ appears to fit well with the straight line associated with the MW _sol . In contrast, sample 16 of the present invention at MW _sol 0.5 × 10 ⁶ _exhibits significantly better crack growth rates than the corresponding control sample due to the much better macro-dispersity D (%) of the sample of the present invention (ie, lowness). This is further established by analogy in FIG. 23, wherein the crack growth rate of sample ninth of the invention comprising N326 carbon black appears to be significantly lower than the corresponding control samples 145-160 and is well below the correlation line. . Similarly, in FIG. 24, the good macro-dispersity of sample ten of the present invention is a crack growth value located far below the correlation between MW _sol and the crack growth rate established by corresponding control samples _177-192. Appears to be. In FIG. 25, the maximum tan δ at 60 ° C. is excellent, ie lower, for samples 24 to 28 of the invention, and samples 29 to 32 of the invention are better than for the corresponding control samples 444 to 450. Is shown graphically.

The excellent crack growth results discussed above for the elastomeric composites of the present invention exhibit favorable fatigue resistance and favorable fracture resistance, such as good tear resistance and cut-and-chip resistance. The excellent hysteresis results discussed above with the elastomeric composites of the present invention present advantageously low rolling resistance (and corresponding higher fuel savings) for automotive tire applications, and show advantageous improvements in related performance properties such as reduced thermal accumulation. . One or more of the above excellent properties, fatigue and fracture resistance, low hysteresis, low heat accumulation and the like make the elastomeric composites of the present invention well suited for use in commercial applications such as tire applications and in industrial rubber articles. With regard to tire applications, various preferred embodiments of the present invention are particularly well suited for the following applications: tire treads, in particular treads for radial and bias truck tires, off-the-wood (“OTR”) tires, airplane tires and the like. ; Subtread; Wire skim; Sidewalls; Cushion rubber for retread tires; And similar tires apply. The good performance characteristics achieved by various preferred embodiments of the present invention can provide improved tire durability, tread life and casing life, good fuel savings for automobiles, and other benefits. With regard to industrial rubber articles, various preferred embodiments of the present invention are particularly well suited for the following uses: engine mounts, hydro mounts, bridge bearings and seismic isolators, tank tracks or treads, mining Application of belts and similar supplies. The good performance characteristics achieved by the various preferred embodiments of the present invention can provide improved fatigue life, durability, and other benefits for such article applications.

26-29 are graphical representations of carbon black morphology, structure (DBPA) and surface area (CTAB) generally corresponding to FIG. 8. In FIG. 26 the carbon black shaped region 261 comprises carbon black, which has recently been used commercially for OTR tire tread applications. Arrow 262 indicates the direction of region 261 which may advantageously extend in accordance with the present invention. Performance characteristics such as cut-and-chip resistance, crack growth resistance, and tear resistance are generally understood to improve in the direction of the direction arrow 262 object, but in the past reduced molecular weight and / or greater surface area of natural rubber It is understood that, due to the poorer macro-dispersity due to the use of less structural carbon blacks, this and other degradation of properties are offset. The elastomeric composites of the present invention may use a smaller structure, larger surface area carbon black, as indicated by the direction arrow 262, to obtain an OTR tread material with good macro-dispersity and significantly improved for MW _sol .

Similarly, the carbon black shaped region 271 in FIG. 27 includes carbon black that has recently been used commercially for truck and bus (T / B) tire tread applications. Arrow 272 indicates the direction of region 271 which may advantageously extend in accordance with the present invention. Performance characteristics such as wear resistance are understood to generally improve in the direction of the direction arrow 272, but in the past due to poor macro-dispersity due to the reduced molecular weight of natural rubber and / or the use of larger surface area carbon blacks. It is understood that this offsets the degradation of these and other properties. The elastomeric composites of the present invention can use the larger surface area carbon blacks indicated by directional arrows 272 to obtain good macro-dispersity and improved T / B tread material for MW _sol .

Similarly, carbon black shaped regions 281 and 283 in FIG. 28 represent carbon black recently used commercially for tread substrates and carriage (PC) tire treads, respectively. Directional arrows 282 and 284 indicate the direction of each region 281 and 283, which may advantageously extend in accordance with the present invention. Performance characteristics such as heat accumulation (HBU) and rolling resistance are understood to improve for the tread substrate in the direction of the direction arrow 282, but in the past the reduced molecular weight and / or larger surface area of rubber, and less structural carbon It is understood that due to the poorer macro-dispersity due to the use of black offsets these and other degradations. Similarly, performance characteristics such as anti-rolling properties are understood to improve for PC treads in the direction of direction arrow 284, but in the past reduced molecular weight of rubber and / or larger surface area, less structure of carbon black It is understood that these and other properties are degraded because of the poorer macro-dispersity resulting from use. The elastomeric composites of the present invention have a larger surface area as indicated by arrows 282 and 284, in order to obtain an improved tread substrate and PC tread, respectively, for good macro-dispersity and arbitrary preservation of high molecular weight in the elastomeric composite, Less structural carbon black can be used.

Similarly, carbon black shaped regions 291, 293, and 294 in FIG. 29 represent carbon blacks that have recently been used commercially for sidewall, vertex, and steel belt tire applications, respectively. Directional arrows 292 and 295 indicate the direction of each region 291 and 294 that can be advantageously extended in accordance with the present invention. Performance characteristics such as heat accumulation (HBU) and fatigue life are understood to improve for the sidewalls in the direction of direction arrow 292, but in the past are more due to the reduced molecular weight of rubber and / or the use of less structural carbon black. It is understood that due to poor macro-dispersity, this and other degradation is canceled out. Similarly, performance characteristics such as heat accumulation, processing and wire adhesion are understood to improve for steel belt elastomeric material in the direction of direction arrow 295, but in the past reduced rubber and / or larger surface area of rubber. It is understood that these and other properties are degraded because of poorer macro-dispersity due to the use of less structural carbon black. The elastomeric composites of the present invention have a larger surface area as indicated by arrows 292 and 295 to obtain improved sidewall and steel belt rubber materials, respectively, for good macro-dispersity and arbitrary preservation of high molecular weight in the elastomeric composites. And / or less structural carbon black may be used.

Additional Examples Control Samples Including Preferred Embodiments and Other Fillers

Samples of addition of the elastomeric composite according to certain preferred embodiments of the present invention, and corresponding control samples were prepared. The first group used multiphase aggregate fillers of the type called silicon treated carbon black.

Specifically, samples 33-34 of the present invention used Ecoblack (ECOBLACK ^(R) ) and siliconized carbon black (Massachusetts, Billerica, Cabot Corporation). The ecoblack filler has similar morphological properties, namely structure and surface area, as carbon black N234. Sample 33 used 45 phr ecoblack filler and no extender oil. Sample 44 used 68 phr ecoblack filler and no extenders. Conventional filler and extender oil applications for various article applications are shown in Table 37 for the inventive elastomeric composites comprising natural rubber and blends of carbon black and silica fillers. The amount of silica filler used in the compositions shown in Table 37 should be understood to typically replace similar amounts of carbon black filler.

TABLE 37

Typical NR Formulations for Tire Applications

The second group of samples used blends or mixtures of silica and carbon black. In embodiments of the invention using blends of carbon black and silica filler, it is generally preferred to use at a weight ratio of at least about 60:40. That is, preferably the carbon black comprises at least about 60% filler by weight to better solidify the elastomer and to reduce or eliminate reagglomeration of the silica in the masterbatch. In particular, as shown in Table 40, in Examples 35-38, carbon black was prepared in a particulate SiO ₂ filler high sil with a surface area of BET 150 m 2 / g, surface area DBPA 190 mils / 100 g, pH 7 and a basic particle size of 19 nanometers. (HiSil ^(R) ) 233 (manufactured by Pittsburgh, PA, PPG Industries, USA).

All samples of the invention, i.e., additional samples 33-38, were prepared according to the methods and apparatus used for Sample 1-32 of the invention described above. Details of the method and apparatus for Samples 33-38 of the present invention are shown in Table 38 below. The field latex or concentrate used in Samples 33-38 is the same as described above in each case with reference to Table 24. It will be appreciated that the data in Table 38 is similar to that provided in Table 25 above for Samples 1-32 of the present invention. The carbon black filler "CRX2000" shown in Table 38 was the eco black (registered trademark), silicon treated carbon black described above.

Table 38

Details on Sample Preparation of the Invention

Control sample 451-498 was prepared according to the methods and apparatus described above for control sample 1-450. Processing codes for masterbatch 451-466 (see Table 13 above), filler loadings, rubber, MW _sol and macro-dispersity are shown in Table 39 below. The processing codes, filler loadings, rubber, MW _sol and macro-dispersity (and filler and oil loadings for easy reference) of Sample 33-38 of the present invention are shown in Table 40. It will be seen from Table 39 that Control Samples 451-466 correspond to Samples 33 and 34 of the present invention in the composition. Similarly, control samples 467-498 correspond to samples 35-38 of the present invention.

TABLE 39

TABLE 40

Sol Molecular Weight and Undispersed Area of Samples of the Invention

Table 41

The superior carbon black dispersion in the masterbatch of Samples 33-38 of the present invention is demonstrated by comparing the macro-dispersity and MW _sol values shown in Table 39-41. Samples 33-34 of the present invention made from Echoblack, silicon treated carbon black, and corresponding control samples were compared in the semi-log curve of FIG. Excellent carbon black dispersion is shown in FIG. 30 for a sample of the present invention indicating a preferred embodiment of the elastomeric composite according to the present disclosure. Advantageously the sample of the present invention is below line 301 in FIG. 30, all control samples are above line 301 and have a much poorer dispersion. In practice, the preferred embodiment shown in FIG. 30 has a D (%) value of less than 0.2% even at MW _sol values which advantageously exceed 0.4 × 10 ⁶ . The data shown in FIG. 30 clearly showed that the macro-dispersion properties of the novel elastomeric composites comprising silicon treated carbon black, disclosed herein, are significantly superior to those obtained using the corresponding components of conventional dry mixing methods. Macro-dispersity values of the elastomeric composites of the invention shown in FIG. 30 are described by the following equation:

[Equation 25]

[Equation 26]

It will be appreciated that D (%) is the undispersed area (percentage) measured for defects of 10 microns or more, and 1% is the critical macro-dispersion characteristic for the masterbatch according to a preferred embodiment of the present invention. That is, even after sufficiently dry mixing the MW _sol to less than 0.4 × 10 ⁶ , none of the dry chewable masterbatches achieved 1.0% or better macro-dispersion properties in any MW _sol . The preferred embodiment shown in FIG. 30 is below the threshold value. It can be seen that the elastomer composites of the present invention comprising silicon treated carbon black provide a balance between the unachieved macro-dispersion properties and the MW _sol .

Samples 35-38 of the present invention, including carbon black blended with silica filler, and corresponding control samples were compared in the semi-log curve of FIG. 31. Specifically, FIG. 31 shows the macro-dispersion and MW _sol values of Samples 35-38 and corresponding Control Samples 467-498 of the present invention. Good carbon black dispersion is shown in the preferred embodiment of the elastomer composite according to the present disclosure and is shown in FIG. 31 for a sample of the present invention. Advantageously, the sample of the present invention is below line 311 in FIG. 31, with all control samples above line 311 and with much poorer dispersion. In practice, all preferred embodiments shown in FIG. 31 have a D (%) value of less than 0.4%. The data shown in FIG. 31 shows that the macro-dispersion properties of the novel elastomeric composites disclosed herein, including carbon black / silica blends, over a range of MW _sol values can be obtained using the corresponding components of conventional dry chewable mixing methods. It is clearly shown to be significantly better. Macro-dispersity values of the elastomeric composites of the present invention shown in FIG. 31 are described by the following equation:

[Equation 27]

[Equation 28]

It will be appreciated that D (%) is the undispersed area (percentage) measured for defects greater than 10 microns and 0.8% is the critical macro-dispersity for masterbatch in accordance with a preferred embodiment of the present invention. That is, even after sufficiently dry mixing the MW _sol to less than 0.4 × 10 ⁶ , none of the dry chewable masterbatches achieved 0.8% or better macro-dispersion properties in any MW _sol . The preferred embodiment shown in FIG. 31 is a marginal macro-dispersity value of less than 0.8% and less than 0.4%. It can be seen that the elastomer composites of the present invention comprising carbon black / silica blend fillers provide a balance between the unachieved macro-dispersion properties and the MW _sol .

With respect to the above disclosure, it will be apparent to those skilled in the art that various attachments, modifications, and the like may be made without departing from the true scope and spirit of the invention. All such additions and variations are intended to be covered by the following claims.

Claims (32)

Supplying a first continuous flow of fluid containing elastomeric latex to the mixing zone of the coagulation bath extending from the mixing zone to the discharge distal end and defining the elongated solidification zone; Supplying a second continuous flow of fluid containing particulate filler effective to coagulate the elastomer latex under pressure to a mixing zone of the coagulation reactor to form a mixture with the elastomer latex and sending the mixture to the discharge end as a continuous flow (Wherein the first fluid and the second fluid are mixed sufficiently strongly in the mixing zone until the discharge end to substantially solidify the elastomeric latex with particulate filler); And Releasing substantially continuous flow of elastomeric composite from the discharging end of the coagulation reactor, Process for preparing elastomeric composites from elastomeric latex, particulate filler and optionally other components. The method of claim 1 wherein the elastomer latex is a natural rubber latex and the particulate filler fluid is an aqueous dispersion of carbon black, silicon treated carbon black, fumed silica, precipitated silica or any mixture thereof. Process for the preparation of elastomeric composites. The method of claim 1 or 2, wherein the second fluid is supplied to the mixing zone through the nozzle at a speed of 30.5 to 244 m / sec (100 to 800 ft / sec), and the first fluid is 3.65 m / sec (12). Pit / sec), continuously fed into the mixing zone. A process according to claim 1 or 2, characterized in that an auxiliary fluid which is substantially unreactive with the mixture is fed to the mixing zone. The method of claim 1, Producing a particulate filler fluid by high energy dispersing particulate filler in an aqueous liquid in a homogenizer; (i) a liquid stream of natural rubber latex continuously less than 3.04 m / sec (10 feet / sec) in the mixing zone defined by the mixing head in sealed fluid connection with the inlet end of the solidification reactor and extending coaxially with the solidification zone. While supplying (ii) through the feed tube substantially coaxial with the coagulation zone (particulate filler fluid exits the feed tube at a rate of 61 to 152.5 m / sec (200 to 500 feet / sec)) at the inlet end of the coagulation zone. Spraying the particulate filler fluid into the mixing zone in the direction to continuously entrain the natural rubber latex into the particulate filler fluid, Creating a continuous flow of natural rubber latex and particulate filler mixture in a coagulation reactor forming generally tubular coagulation zones extending gradually with increasing cross-sectional area from the inlet end to the outlet end; Continuously discharging, from the discharge distal end of the coagulation bath, a master batch glob that substantially solidifies coagulation of the natural rubber latex by particulate filler; And Continuously drying and pelletizing the master batch globble discharged from the coagulation reactor in one or more dryers, And wherein the particulate filler is selected from carbon black, silicon treated carbon black, fumed silica, precipitated silica and mixtures thereof, wherein the elastomer comprises natural rubber. A coagulation reactor defining a blend zone and an elongated coagulation zone extending from the blend zone to the discharge end; Latex supply means for continuously supplying an elastomer latex fluid to the mixing zone; And And filler supply means for supplying particulate filler fluid as a continuous jet into the blending zone to form a mixture with the elastomeric latex fluid that travels from the blending zone to the discharge end of the coagulation zone. Apparatus for producing an elastomeric composite comprising particulate filler dispersed in an elastomer. An elastomeric composite comprising particulate filler dispersed in an elastomer, characterized in that the macro-dispersity D (%) of the particulate filler in the elastomeric composite is less than 1.0% undispersed area. 8. The elastomeric composite of claim 7, wherein the particulate filler is present in an amount of at least 30 phr. 8. The method of claim 7, wherein the elastomer is a natural rubber, the particulate filler is from 30 to 75 phr of carbon black having a structure-to-surface area ratio DBPA: CTAB of less than 1.2, and the macro-dispersity D (%) is 0.3% or less. Elastomer complex. The elastomeric composite according to claim 9, wherein the surface area CTAB of the carbon black is 45 or more. The elastomeric composite according to claim 9 or 10, wherein the MW _sol (weight average) is at least 0.45 × 10 ⁶ and not vulcanized. The method of claim 7, wherein the elastomer comprises natural rubber and the particulate filler comprises 30 to 75 phr of carbon black having a surface area CTAB of at least 45 and less than 250, The macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) ≤ 0.2% when MW _sol <0.45 x 10 ⁶ and (ii) 0.45 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ Wherein when the log (D) ≤ log (0.2) + 2.0 x (MW _sol -0.45 x 10 ⁶ ) x 10 ^-6 . 8. The method of claim 7, wherein the elastomer comprises natural rubber and the particulate filler has a surface area CTAB of at least 45 and 250 and a CTAB of at least 65 and less than 250, DBPA (cc / 100 g) is less than 110 and CTAB is at least 45 and If less than 65, it contains 30 to 75 phr of carbon black with a DBPA of less than 80 + 1.6 (CTAB-45), The macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) <1.0% when the MW _sol is less than 0.7 x 10 ⁶ , and (ii) 0.7 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ days when the log (D) <log1.0 + 2.5 x (MW sol - 0.7 x 10 6) x 10 -6 in the elastomer composite, characterized in that. The method of claim 7 wherein the elastomer comprises natural rubber and the particulate filler comprises 30 to 75 phr of carbon black having a structure DBPA of at least 110 and less than 80 + 1.6 (CTAB-45) and a surface area CTAB of at least 65 and less than 250. Include, Macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) <0.3% when MW _sol is less than 0.35 x 10 ⁶ , and (ii) 0.35 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ days when the log (D) <log (0.3 ) + 2.8 (MW sol - 0.35 x 10 6) x 10 -6 in the elastomer composite, characterized in that. 8. The composition of claim 7 wherein the elastomer comprises natural rubber and the particulate filler has a structure DBPA (cc / 100g) of 80 + 1.6 (CTAB-45) to 160 and a surface area CTAB of from 45 to 90 and less than 40 to 70 phr. Contains carbon black, The macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) <0.1% when MW _sol is less than 0.35 x 10 ⁶ , and (ii) 0.3 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ days when the log (D) <log (0.1 ) + 2.0 x (MW sol - 0.30 x 10 6) x 10 -6 in the elastomer composite, characterized in that. 8. The method of claim 7, wherein the elastomer comprises natural rubber and the particulate filler comprises 30 to 70 phr particulate filler comprising a blend of carbon black and silica, The macro-dispersity D (%) of the particulate filler in natural rubber is (i) D (%) <0.8% when the MW _sol is less than 0.5 x 10 ⁶ , and (ii) 0.5 x 10 ⁶ <MW _sol <1.1 x Elastomer composite, characterized in that when 10 ⁶ log (D) <log (0.8) + 2.2 x (MW _sol -0.5 x 10 ⁶ ) x 10 ^-6 . 17. The elastomeric composite of claim 16, wherein the particulate filler comprises at least about 60% carbon black. The method of claim 7, wherein the elastomer comprises natural rubber, the particulate filler comprises from 30 to 70 phr siliconized carbon black, The macro-dispersity D (%) of _siliconized carbon black in natural rubber is (i) D (%) <1.0% when the MW _sol is less than 0.4 x 10 ⁶ , and (ii) 0.4 x 10 ⁶ <MW _sol < Elastomer complex, characterized in that log (D) <log (1.0) + 2.0 x (MW _sol -0.4 x 10 ⁶ ) x 10 ^-6 when 1.1 x 10 ⁶ . A cured elastomeric composite, comprising the elastomeric composite of any one of claims 12-18. 20. A vulcanizate comprising the cured elastomeric composite or elastomeric composite of any of claims 12-19 having a crack growth rate of about 1.20 cm / million cycles or less as measured in accordance with ASTM D3629-94. The vulcanizate according to claim 20, wherein the crack growth rate measured according to ASTM D3629-94 is about 1.20 cm / million cycles or less. 8. The elastomeric composite of claim 7, wherein the particulate filler is carbon black, silicon coated carbon black, silicon treated carbon black, fumed silica, precipitated silica or any mixture thereof. The method according to claim 7, wherein the elastomer is natural rubber, chlorinated derivatives of natural rubber, or butadiene, styrene, isoprene, isobutylene, 3,3-dialkyl-1,3-butadiene, wherein the alkyl group is C ₁ to C ₃ alkyl, Elastomer composite, characterized in that the homopolymer, copolymer or terpolymer of acrylonitrile, ethylene or propylene. 9. The elastomeric composite of claim 8, further comprising at least one additive selected from antiozonants, antioxidants, plasticizers, processing aids, resins, flame retardants, extender oils, lubricants and any mixtures thereof. 8. The elastomeric composite of claim 7, comprising at least 30 phr of carbon black. 8. The elastomeric composite of claim 7, further comprising an extender oil of greater than 0 to 20 phr. 13. The method of claim 12 wherein the elastomer comprises natural rubber and the particulate filler comprises 30 to 75 phr of carbon black having a surface area CTAB of at least 45 and less than 250, Further comprising greater than 0 to 20 phr extender oil, wherein the macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) ≦ 0.2% when MW _sol ≦ 0.45 × 10 ⁶ ) Elastomer composite, characterized in that when (0.45 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ ) log (D) <log (0.2) + 2.0 x (MW _sol -0.45 x 10 ⁶ ) x 10 ^-6 . The method according to claim 13, wherein the elastomer comprises natural rubber, and the particulate filler has a surface area CTAB of at least 45 to 250 and a CTAB of at least 65 to less than 250, DBPA (cc / 100 g) of less than 110 and CTAB of at least 45 If less than 65, it contains 30 to 75 phr of carbon black with a DBPA of less than 80 + 1.6 (CTAB-45), Further comprising greater than 0 to 20 phr extender oil, wherein the macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) <1.0% when MW _sol is less than 0.7 × 10 ⁶ , ii) Elastomer composite, characterized in that log (D) <log 1.0 + 2.5 x (MW _sol -0.7 x 10 ⁶ ) x 10 ^-6 when 0.7 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ . 15. The carbon black of claim 14 wherein the elastomer comprises natural rubber and the particulate filler comprises 30 to 75 phr of carbon black having a structure DBPA of at least 110 to less than 80 + 1.6 (CTAB-45) and a surface area of CTAB of at least 65 to less than 250. Include, Further comprising greater than 0 to 20 phr of extender oil, wherein the macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) <0.3% when the MW _sol is less than 0.35 × 10 ⁶ ; ii) Elastomer composite, characterized in that log (D) <log (0.3) + 2.8 (MW _sol -0.35 x 10 ⁶ ) x 10 ^-6 when 0.35 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ . 16. The composition of claim 15 wherein the elastomer comprises natural rubber and the particulate filler has a structure DBPA (cc / 100g) of 80 + 1.6 (CTAB-45) to 160 and a surface area CTAB of 45 to 90 and less than 40 to 70 phr. Contains carbon black, Further comprising greater than 0 to 20 phr extender oil, wherein the macro-dispersity D (%) of carbon black in natural rubber is (i) D (%) <0.1% when MW _sol is less than 0.35 × 10 ⁶ , ( ii) Elastomer composite, characterized in that log (D) <log (0.1) + 2.0 x (MW _sol -0.30 x 10 ⁶ ) x 10 ^-6 when 0.3 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ . 17. The particulate matter of claim 16, wherein the elastomer comprises natural rubber, the particulate filler comprises 30 to 70 phr particulate filler comprising a blend of carbon black and silica, Further comprising greater than 0 to 20 phr extender oil, wherein the macro-dispersity D (%) of the particulate filler in the natural rubber is (i) D (%) <0.8% when the MW _sol is less than 0.5 x 10 ⁶ , (ii) an elastomeric composite characterized in that log (D) <log (0.8) + 2.2 x (MW _sol -0.5 x 10 ⁶ ) x 10 ^-6 when 0.5 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ . 19. The method of claim 18, wherein the elastomer comprises natural rubber, the particulate filler comprises 30 to 70 phr of siliconized carbon black, Further comprising greater than 0 to 20 phr extender oil, wherein the macro-dispersity D (%) of the _siliconized carbon black in natural rubber is (i) D (%) <1.0% when the MW _sol is less than 0.4 x 10 ⁶ (Ii) an elastomer characterized in that log (D) <log (1.0) + 2.0 x (MW _sol -0.4 x 10 ⁶ ) x 10 ^-6 when 0.4 x 10 ⁶ <MW _sol <1.1 x 10 ⁶ Complex.