WO2022066105A1

WO2022066105A1 - Machine for preparing rubber masterbatch from rubber latex and fillers and a process thereof

Info

Publication number: WO2022066105A1
Application number: PCT/TH2021/000049
Authority: WO
Inventors: Sittikorn LAPAPONG; Rattanasuda NAEWNGERNDEE; Jomkwun MUNNAE; Anek PHUCHAMNONG; Chaveewan Kongkaew; Piyada SUWANDITTAKUL; Suriyakamon Montha; Anusorn IAMRURKSIRI; Krisda TAPRACHAROEN; Sorayot CHINKANJANAROT; Surachai RODSAI; Siwaporn SRIMONGKOL
Original assignee: National Science And Technology Development Agency
Priority date: 2020-09-28
Filing date: 2021-09-06
Publication date: 2022-03-31

Abstract

The present invention relates to a pin mixer for rubber masterbatch production comprising a latex container (102) for storing the latex, a latex feeding control unit (104) for regulating the latex feeding rate, a filler container (105) for retaining a filler, a filler feeding control unit (107) for controlling the filler feed rate, a mixing chamber (108) where the mixing between the latex and the filler takes place to produce rubber masterbatch, and a stirring drive unit (200) where a shaft (202) is axially installed into the mixing chamber (108). The shaft (202) comprises a plurality of pins (206) affixed on the surface of shaft (202) from one shaft end to the other end which provide good dispersion and uniformity of the mixture therein to efficiently form the rubber composite.

Description

MACHINE FOR PREPARING RUBBER MASTERBATCH FROM RUBBER LATEX AND FILLERS AND A PROCESS THEREOF

FIELD OF THE INVENTION

The invention relates to machine for preparing rubber masterbatch from rubber latex and fillers and a process thereof.

BACKGROUND OF THE INVENTION

A rubber masterbatch is a process of mixing rubber with one or more additives or fillers that will improve the mechanical properties of the composites. In rubber industries, various types of fillers are imparted in the rubber matrix for different compounding characteristics such as to enhance tensile strength, wear resistance, rolling resistance, UV protection, electrical conductivity, or heat resistance. Sometimes a magnetic filler is added to expedite vulcanization.

The conventional rubber masterbatch process can be categorized into two processes, which are:

1. A dry-mixing masterbatch is a mixing process of rubber sheets or rubber crepes with the filler added by mechanical means in a solid phase. This process can be a batch process such as a Banbury internal mixer, an intermix internal mixer, or a kneader. Or it can be a continuous mixer such as a single screw or a twin screw mixer. However, this blending operation is not environmentally friendly and safe because some fillers are extremely lightweight and easily spread into the atmosphere, creating air pollution during the mixing process which is harmful to the respiratory system of the workers. The process encounters ununiform dispersion of the filler and requires high energy consumption over a long period of manufacturing time. Moreover, some solids contaminated in the rubber crepe or sheet may cause unexpected damage to the machines used.

2. A wet compounding masterbatch is a process where a filler and a dispersing solvent are mixed with rubber latex in an aqueous phase by a mechanical force to obtain a slurry solution. The slurry' is then solidified by an acid. The wet compounding can improve the dispersibility of the fillers, providing more uniform reinforcement throughout the rubber matrix, resulting in enhancing the mechanical properties of the composites. This method reduces air pollution, so the process is more environmentally friendly. However, the process still needs some improvement in filler dispersibility. Additionally, the process requires more equipment and machines for the predetermined mixing process and costly wastewater treatment due to acidity leftover from the cleansing process.

The conventional processes in rubber industries are not environmentally friendly causing air, water, and soil pollution. Especially in rubber production from natural latex, the process requires an acidic solution for latex coagulation or solidification resulting in a need to wash the acid out before further processing in other stages. A variety of chemicals is used during the manufacturing steps. A great amount of washing wastewater is daily discharged and needs suitable treatment. Improper treatment of the acidic rubber wastewater may cause effluent and become hazardous to people living nearby. For these reasons, it is essential to develop a novel rubber manufacturing process that is more friendly to the environment,

U.S. Pat. No. 6,929,783 B2 disclosed a continuous elastomer masterbatch process whereas a particulate filler fluid is fed through the mixing zone under high pressure, forming a jet stream, such that the filler is completely coagulated with the elastomer latex without requiring an acid or salt as a coagulation agent. The coagulated elastomer composites are processed through continuous compounders where moisture level and mooney viscosity can be controlled. The process gives the ad vantage of no coagulation agent being needed. However, this method requires specific and complex machinery with a fully controlled efficacy environment.

U.S. Pat. No. 8,586,651 disclosed an alternative elastomer composite production. The continuous process comprises 5 steps where the elastomer latex is combined with a particulate filler in step 1. Step 2 is to coagulate the mixing fluid into the masterbatch crumb. Then water content is added to the masterbatch crumb in step 3. Step 4 is to dewater the coagulum crumb by a mechanical means. Lastly, the dewatered coagulum is heated by friction so that the water content is substantially vaporized yielding a consistent microstructure of the compound that can be reproducible. However, this method requires a variety of special equipment with high manufacturing investment.

TH 1,701,004,383 disclosed a mixing machine for combining a rubber latex with a filler to obtain a rubber masterbatch. This process does not require filler preparation in the aqueous solution and there is no need for an acidic solution to solidify the latex composite. As a result, there is no acidic wastewater during the process of production. The mixing machine comprises a latex container, a filler container, a controller, a mixing container with a motor, an agitator, and a wiping blade attached to the mixing container. The agitator is a spiral and works together with the wiping blade to uniformly create dispersion. Unfortunately, the aforementioned machine only includes the spiral agitator with spaces in between with no pin mixer for a better mixing result.

U.S. Pat. No. 10,253,141 B2 disclosed a continuous wet-rubber masterbatch using a singlescrew extruder. The extruder comprises a screw and an external cylinder in which a slit is attached to an internal wali surface of the cylinder along the length of the cylinder. Nevertheless, the process still requires some chemical agent for coagulation and needs filler preparation in a slurry solution.

The objective of this invention is to develop a continuous natural rubber masterbatch utilizing a high-shear pin mixer. A set of pins is radially attached outward of a shaft to efficiently improve homogeneity and uniformity of latex composition reinforcement, yielding the rubber crumb that can be dried easily and is more convenient to be used as a raw material in rubber industries.

SUMMARY OF THE INVENTION

The present invention relates to a pin mixer for a natural rubber masterbatch production. The pm mixer is specially designed so that a plurality of pins is radially affixed outward on a shaft so that the filler can be well dispersed throughout the latex. As a result, the latex and filler are completely⁷ mixed in the mixing chamber. The mixture or the rubber masterbatch obtained from this process yields uniform and similar rubber crumb qualities. The present pin mixer is comprised of

— a latex container ( 102) for storing the latex having a latex outlet (103) at one end to transfer the latex to a latex feeding control unit (104)

— the latex feeding control unit (104) installed at the latex outlet (103) for controlling the latex feeding rate to a mixing chamber (108).

— a filler container (105) for retaining a filler having a filler outlet (106) at one end of the container for transferring the filler to a filler feeding control unit (107).

— the filler feeding control unit (107) installed at the filler outlet (106) for controlling a filler feeding rate to a mixing chamber (108). — the mixing chamber (108) connected to the latex feeding control unit (104) through a latex inlet (109) and connected to the filler feeding control unit (107) through a filler inlet (110) for mixing the latex with the filler to produce rubber masterbatch.

— a stirring drive unit (200) comprising a shaft (202) axially installed into the mixing chamber (108) for stirring the mixture and a stirring driven component (204) attached at one end of the shaft (202) for controll ing the rotating speed of the shaft (202). wherein the shaft (202) comprises a plural ity of pins (206) affixed on the surface of shaft (202) from one end to the other end with the ratio of the distance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 1 to 100.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 shows the com ponents of the pin m ixer for the rubber masterbatch production

Figure 2 shows the pm arrangement onto and around the shaft of the pm mixer

Figure 3 shows images of the rubber masterbatch crumb of which carbon black is an example of the filler mixes with the latex a) before drying b) after drying

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a pin mixer for rubber masterbatch production utilizing a plurality of pins radially affixed outward on a shaft so that a filler and the latex can be mixed with better dispersion and uniformity.

Technical terms or scientific definitions described and claimed herein shall be interpreted in the context of the present invention and are obvious for one skilled in the art to understand. Thus, the interpretation excludes other definitions of technical or scientific terms that may be specifically discussed further in other contexts of the full disclosure of the invention.

Definition

Technical terms or scientific definitions described and claimed herein shall be construed in the context of the present invention and are obvious for those skilled in the art to understand. Thus, the interpretation excludes other definitions of technical or scientific terms that may be specifically discussed further in other contexts of the full disclosure of the inventi on.

Any tools, equipment, methods, or any chemical substances mentioned herein are meant to tools, equipment, methods, or chemical substances commonly used by those skilled in the field of art unless otherwise expressly stated as a special tool, equipment, method, or chemical substance for the present invention.

Singular nouns or singular pronouns when used with the terms “comprise of’ or “to comprise of’ in the claims or the detail of the description of the invention means “one” and shall include “one or more,” “at least one,” and “one or more than one”.

As used herein, throughout this application, the terms “about” or “estimate” are used to indicate that any expressed or presented value herein may be varied or deviate. Such variation or deviation may be caused by equipment discrepancy, the method used to determine the presented value or the person who uses the equipment or performs the determination method according to the procedures. It is understood that by the use of the antecedent “about” or “approximate”, the presented value is not and need not be exact and is intended to convey that some other values approximately or about the same values promote similar effects recited in all the methods and/or processes disclosed herein and in the claims.

The qualification of the present invention as the resu lt of an action, performance, modification, or change in any factor insignificantly different from the present invention that yields a similar or equivalent qualification of the present invention, by those who are skilled in the art, though not specifically stated in the claims, including any insignificant modification or changes that are apparent to those who are skilled in the art, may be considered being within the scope of this invention as described in the attached claims

The detailed description of the inventi on which is not restrictive to the aspects of the invention is presented as follows:

According to one embodiment of the invention, the invention relates to a pm mixer for rubber masterbatch production that comprises — a latex container (102) for storing the latex having a latex outlet (103) at one end to transfer the latex to the latex feeding control unit (104)

— the latex feeding control unit (104) installed at the latex outlet (103) for controlling the latex feeding rate to the mixing chamber (108).

— a filler container (105) for retaining a filler having a filler outlet (106) at one end of the container for transferring the filler to the filler feeding control unit (107).

— the filler feeding control unit (107) installed at the filler outlet (106) for controlling the filler feeding rate to the mixing chamber (108).

— the mixing chamber (108) connected to the latex feeding control unit (104) through a latex inlet (109) and connected to the filler feeding control unit (107) through a filler inlet (110) for mixing the latex with the filler to produce rubber masterbatch.

— a stirring drive unit (200) comprising a shaft (202) axially installed into the mixing chamber (108) for stirring the mixture and a stirring driven component (204) attached at one end of the shaft (202) for controll ing the rotating speed of the shaft (202). wherein the shaft (202) comprises a plurality of pins (206) affixed on the surface of shaft (202) from one end to the other end with the ratio of the di stance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 1 to 100.

According to one aspect of the invention, the pins have the ratio of the distance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range between 3 to 60 in one aspect. The pins (206) can be arranged on the surface of the shaft (202) in a manner that can be selected from a circular, helix, or a random pattern.

In one aspect of the invention, the number of pins (206) per loop ranges between 2 to 16 pins.

In another preferred aspect of the invention, the number of pins (206) per loop ranges between

4 to 12 pins In one aspect of the invention, the pins (206) have a pitch distance in the range of 4 to 20 centimeters.

In another preferred aspect of the invention, the pins (206) have a pitch distance in the range of 6 to 12 centimeters.

In one aspect of the invention, the pins (206) have the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 0.2 to 3 centimeters.

In another preferred aspect of the invention, the pins (206) have the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 0.2 to 2 centimeters.

In one aspect of the invention, the pins (206) can be in the shape selected from a cylinder or polyhedron.

In one aspect of the invention, the mixing chamber (108) can be in the shape selected from a cylinder, cubic, or polyhedron.

In another preferred aspect of the invention, the mixing chamber (108) is a longitudinal cylinder where the latex and a filler are fed through inlets located on the top and an outlet located at the bottom for conveying the latex composition out of the mixing chamber (108) to accommodate the continuous mixing process.

In another preferred aspect of the invention, the mixing chamber (108) has a length in the range of 300 to 4,000 centimeters.

In another preferred aspect of the invention, the mixing chamber (108) has a length in the range of 500 to 3,000 centimeters.

In one aspect of the invention, the latex feeding control unit (104) is a pump.

In one aspect of the invention, the filler feeding control unit (107) is conveying equipment that can be selected from a belt conveyor or a screw conveyor In another embodiment of the invention, the process of producing the rubber masterbatch comprises the following steps: a) providing the pin mixer comprising

— a latex container (102) for storing the latex having a latex outlet (103) at one end to transfer the latex to the latex feeding control unit (104)

— a filler container ( 105) for retaining a filler having a filler outlet (106) at one end of the container for transferring the filler to the filler feeding control unit (107).

— a stirring drive unit (200) comprising a shaft (202) axially installed into the mixing chamber (108) for stirring the mixture and a stirring driven component (204) attached at one end of the shaft (202) for controlling the rotation speed of the shaft (202). b) feeding the latex and the filler to the mixing chamber (108) with the ratio of the filler to the latex in the range from 0.3:1 to 2: 1 c) agitating the latex and the filler in the mixing chamber (108) with a stirring speed in the range of 500 to 2,500 rpm d) drying the mixture obtained from step c) then collecting the resultant rubber masterbatch wherein the shaft (202) comprises a plurality of pins (206) affixed on the surface of shaft (202) from one end to the other end with the ratio of the distance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 1 to 100.

In a preferred aspect of the invention, step b) requires the filler to the rubber content ratio in the range of 0.4 : 1 to 1.4:1.

In another preferred aspect of the invention, step b) requires the latex to have a dry rubber content in the range of 20% to 60% by weight.

In another preferred aspect of the invention, step b) the latex is fed into the mixing chamber (108) at a feed rate in the range of 0.5 to 50 liters per minute.

In another preferred aspect of the invention, step b) the filler is fed into the mixing chamber (108) at a feed rate in the range of 0.5 to 50 kilograms per minute.

In another preferred aspect of the invention, step c) stirring rate is at 500 to 1,000 rpm

In another preferred aspect of the invention, step d) drying process of the mixture can be selected from the desiccation drying process, the convective or the hot air drying process, the low pressure or the vacuum drying process, the microwave or the electromagnetic drying process, the heat pump drying, the fluidized bed drying, or a combination thereof.

In another aspect of the invention, in step a) the pin mixer has additional specifications as described above.

The principles of the present invention will become more apparent from the following examples which illustrate as explanatory and exemplary embodiments of the present invention only and therefore are not intended to be limiting. The scope of the present invention should be defined only by the claims and their equivalents.

Examples of the Invention

The latex-filler mixer for producing the rubber masterbatch described in this invention is a pin mixer, of which the appearance of the mixer can be in any shape. The main component is the mixing chamber (108) in which comprises a shaft (202) with a plurality of pins, with any geometric shape, affixed radially outward onto and around the shaft (202) for agitating the mixture. The latex is mixed with the filler in the mixing chamber (108) to produce the rubber masterbatch where a latex container (102) is connected to the latex feeding control unit (104), regulating the flow rate and the amount of the latex solution to the mixing chamber (108). A filler container (105) is connected to the filler feeding control unit (107) for delivering the filler into the mixing chamber (108) where an electric motor is the mam power source to drive the shaft (202) located inside the mixing chamber (108). The latex solution and the filler are agitated by the pins (206) affixed onto and around the shaft (202) so that the filler is well dispersed and the mixing process can be completed yielding the rubber masterbatch. Figures 1 and 2 illustrate examples of one aspect of the pin mixer in accordance with the present invention.

The latex container (102) may resemble a cylindrical tank with a conical tip made out of polymer or metal materials. It can be installed above, below, or at the same level as the mixing chamber (108). It retains the latex solution before releasing the latex solution into the mixing chamber (108) through the latex feeding control unit (104).

The latex feeding control unit (104) located at the bottom of the latex container (102) serves to close-open the latex solution supply and control the amount and flow rate of the latex solution through the latex outlet (103) before entering the mixing room (108), using a pump to transfer the latex solution from the latex container (102) to the mixing chamber (108).

The filler container (105) that may resemble a cylindrical tank with a conical tip made of polymer or metal materials is installed above, below, or at the same level as the mixing chamber (108). It retains the filler before feeding into the mixing chamber (108) through the filler feeding control unit (107).

The filler feeding control unit (107) located at the bottom of the filler container (105) serves to transport the filler and control the feed rate and amount of the filler delivered from the filler outlet (106) before entering the mixing chamber (108), using conveying equipment to feed the filler into the mixing chamber (108). The mixing chamber (108) is made of polymer or metal materials with an appearance of a cylinder or any geometric shape with an approximate length of 300 to 4,000 centimeters. It can be installed above, below, or at the same level as the latex container (102) and serves as a mixing room where the latex and the filler or any chemical substance are mixed. The mixing chamber (108) may perform the mixing between the latex with the filler, including carbon black, silica, or calcium carbonate with the ratio by weight of the filler to the rubber content in the range of 0.3-2 to 1. The mixing chamber (108) is a closed system where there is no burst of the latex and the filler spreading during the mixing process.

The stirring drive (200) comprises a shaft (202) that longitudinally extends through the elongated conduit of the mixing chamber (108). The stirring drive (204) is an electric motor, connected at one end of the shaft (202), controlling the rotational speed of the shaft (202). The shaft (202), made of polymer or metal material and can be a cylinder or any geometric shape, is installed at the center of the mixing chamber (108) to which a plurality of pins (206) can be attached. The shaft (202) is connected to the stirring drive (204) to allow shaft rotation. The pins (206), serve as agitators to mix the latex with the filler, may be made of polymer or metal material, and can be in a cylinder, polyhedron, or any geometric shape. The pins (206) are arranged onto and around the shaft (202) from one end to the other end of the shaft (202) where the distance between the inner wall of the mixing chamber (108) and the tip of the pins (206) is in the range of 0.2 to 0.3 centimeters. Along the longitudinal shaft (202), the pins (206) can be arranged in different patterns with a variety of pitch distance of the pins (206) for each loop (202). The pitch distance is in the range of 4 to 20 centimeters and the number of pins (206) in one loop of each pitch can range from 2 to 16 pins.

The pin mixer for rubber masterbatch production described herein is applicable to produce the rubber masterbatch without requiring the filler preparation to be an aqueous slurry prior to the mixing process and there is no need for an acidic solution to coagulate the rubber composite. The filler disperses well into the rubber so formation of the rubber composite can occur in a short period. The rubber masterbatch described herein can be applied to natural or synthetic rubber. The method comprises the steps of: a) The mixing process of the latex and the filler The filler powder and the latex are fed into the mixing chamber (108) with the controlled feed rate and amounts of the filler and the latex according to the predetermined concentration of the rubber masterbatch. Then the mixture is agitated with the predetermined ratio by weight between the filler and the latex at 0.3 - 2; 1 , preferably a ratio of 0.4 - 1.4: 1.0, with the latex concentration in the range of 20% to 60%, but which is more advantageous at 25% to 35%. The agitation speed is in the range of 500 to 2,500 rpm and a suitable speed is in the range of 500 to 1,000 rpm. b) Drying process of the rubber masterbatch

The mixed composite or the rubber masterbatch obtained from step a) can be dried with several drying techniques including the desiccation drying process, the convective or the hot air drying process, the low pressure or the vacuum drying process, the microwave or the electromagnetic drying process, the heat pump drying, the fluidized bed drying, or a combination thereof. After the drying process, the resultant dried mixture or the dried rubber masterbatch can be made in pallets, sheets, or crepes.

The mixing process of the rubber masterbatch production described herein allows the latex to be directly mixed with the powder filler where the fl ow' rate and the amount of the latex are determined according to the preferrable rubber masterbatch concentration and the dry rubber content (DRC) of the latex. Then the mixtures are stirred until the composite becomes homogeneous. The filler is dispersed in the latex so the mixing can be completed without waste water. The rubber masterbatch production can be a continuous process at which the resultant rubber compound prepared from the present rubber masterbatch requires less time for vulcanization and at a lower temperature. Its mechanical properties are similar compared to conventional rubber masterbatch production. In addition, the principles, examples, or procedures used in the present rubber masterbatch production described herein can be applied to the production of rubber masterbatches either in a batch process or continuous process without any intention to limit the scope of the invention.

Example of the invention

Prepared the carbon black and the latex of which the rubber content was 30% with the predetermined feed rate and amount of latex and carbon black to the mixing chamber (108) with the ratio between the carbon black to the latex content at 0.8 to 1.0. The shaft (202) rotation speed was approximately at 500 to 1,000 rpm where the pins (206) arrangement on and around the shaft (206) had a pitch distance of approximately 6 to 12 centimeters. The number of pins (206) for a loop of each pitch may be approximately 4 to 12 pins and the distance between the inner wall of the mixing chamber (108) to the tip of the pins (206) was approximately 0.2 to 2 centimeters.

The rubber masterbatch obtained by the present rubber masterbatch production process with the pm mixer described herein was illustrated in Figure 3a. The resultant rubber masterbatch was small black crumbs whose col lected total solid content was close to 100% of the total weight. The resultant rubber masterbatch crumbs were dried as shown in Figure 3b, where the rubber composite clumps together into larger lumps with no carbon black coming out.

The principle of the device and the methodology described herein is intended to disclose the qualification of the present invention that is not acted, performed, modified, or changed any factor significantly different from the present invention. The resultant qualification and benefits of use are equivalent or similar to the qualification of the present invention, in accordance with those who are skilled m the art. Though not specifically stated in the claims, any substitution or similar qualification to those described herein, which include any modifications and minimal changes that are apparent to those who are skilled in the art, may be considered being in the scope of this invention as described in the attached claims.

THE BEST MODE OF THE INVENTION

As mentioned in the detailed description of the invention.

Claims

We claim:

1. A pin mixer for rubber masterbatch production, comprising;

— a latex container (102) for storing the latex having a latex outlet (103) at one end to transfer the latex to a latex feeding control unit (104),

— the latex feeding control unit (104) installed at the latex outlet (103) for controlling the latex feeding rate to the mixing chamber (108),

— a filler container (105) for retaining a filler having a filler outlet (106) at one end of the container for transferring the filler to a filler feeding control unit (107),

— the filler feeding control unit (107) installed at the filler outlet (106) for controlling the filler feeding rate to a mixing chamber (108),

— the mixing chamber (108) connected to the latex feeding control unit (104) through a latex inlet (109) and connected to the filler feeding control unit (107) through a filler inlet (110) for mixing the latex with the filler to produce rubber masterbatch,

— a stirring drive unit (200) comprising a shaft (202) axially installed into the mixing chamber (108) to stir the mixture and a stirring driven component (204) attached at one end of the shaft (202) to control the rotation speed of the shaft (202). wherein the shaft (202) comprises a plurality of pins (206) affixed on the surface of shaft (202) from one end to the other end with the ratio of the distance between each pin to the distance between the tip of the pm (206) to the wall of mixing chamber (108) in the range of 1 to 100.

2. The pin mixer of claim 1, wherein the pins (206) have the ratio of the distance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 3 to 60.

3. The pin mixer of claim 1, wherein the pins (206) can be arranged onto the surface of the shaft (202) in a manner that can be selected from a circular, a helix, or a random pattern.

4. The pin mixer of claim 1, wherein the number of pins (206) per loop ranges between 2 to 16 pins.

5. The pm mixer of claim 4, wherein the number of pins (206) per loop ranges between 4 to 12 pins.

6. The pm mixer of claim 1, wherein the pins (206) have the pitch distance in the range of 4 to 20 centimeters.

7. The pm mixer of claim 6, wherein the pins (206) have the pitch distance in the range of 6 to 12 centimeters.

8. The pin mixer of claim I , wherein the pins (206) have the distance between the tip of the pm (206) to the wall of mixing chamber (108) in the range of 0.2 to 3 centimeters.

9. The pin mixer of claim 8, wherein the pins (206) have the distance between the tip of the pm (206) to the wall of mixing chamber (108) in the range of 0.2 to 2 centimeters.

10. The pm mixer of claim 1, wherein the pins (206) can be in the shape selected from a cylinder or polyhedron.

11. The pin mixer of claim 1, wherein the mixing chamber (108) can be in the shape selected from cylinder, cubic, or polyhedron.

12. The pin mixer of claim 11 , wherein the mixing chamber (108) is a longitudinal cylinder where the latex and a filler are fed through inlets located on the top and the latex composition is conveyed through an outlet located at the botom of the mixing chamber (108) to accommodate the continuous mixing process.

13. The pin mixer of claim 1, wherein the mixing chamber (108) has a length in the range of 300 to 4,000 centimeters. The pin mixer of claim 13, wherein the mixing chamber (108) has a length in the range of 500 to 3,000 centimeters. The pin mixer of claim 1, wherein the latex feeding control unit (104) is a pump. The pin mixer of claim 1, wherein the filler feeding control unit (107) is conveying equipment that can be selected from a belt conveyor or a screw conveyor. A method of rubber masterbatch production, comprising the steps of a) providing the pm mixer comprising:

- a latex container (102) for storing the latex having a latex outlet (103) at one end to transfer the latex to a latex feeding control unit (104), the latex feeding control unit (104) installed at the latex outlet (103) for controlling the latex feeding rate to the mixing chamber (108),

- a filler container (105) for retaining a filler having a filler outlet (106) at one end of the container for transferring the filler to a filler feeding control unit (107), the filler feeding control unit (107) installed at the filler outlet (106) for controlling the additive feeding rate to a mixing chamber ( 108),

- the mixing chamber (108) connected to the latex feeding control unit (104) through a latex inlet (109) and connected to the filler feeding control unit (107) through a filler mlet (110) for mixing the latex with the filler to produce rubber masterbatch,

- a stirring drive unit (200) comprising a shaft (202) axially installed into the mixing chamber (108) to stir the mixture and a stirring driven component (204) attached at one end of the shaft (202) to control the rotation speed of the shaft (202). b) feeding the latex and the filler to the mixing chamber (108) with the ratio of the filler to the rubber content in the range of 0.3: 1 to 2: 1 c) agitating the latex and the filler in the mixing chamber (108) with a stirring speed in the range of 500 to 2,500 rpm d) drying the mixture obtained from step c) then collecting the resultant rubber masterbatch wherein the shaft (202) comprises a plurality of pins (206) affixed on the surface of shaft (202) from one end to the other end with the ratio of the distance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 1 to 100.

18. The method of claim 17, wherein step b) requires the filler to the rubber content ratio in the range of 0.4:1 to 1.4: 1

19. The method of claim 17, wherein step b) requires the latex to have a dry rubber content in the range of 20% to 60% by volume

20. The method of claim 17, wherein step b) the latex is fed into the mixing chamber (108) at a feed rate in the range of 0.5 to 50 liters per minute

21. The method of claim 17, wherein step b) the filler is fed into the mixing chamber (108) at a feed rate in the range of 0.5 to 50 kilograms per minute

22. The method of claim 17, wherein step c) the stirring speed is in the range of 500 to 1,000 rpm.

23. The method of claim 17, wherein step d) the drying process of the mixture can be selected from the desiccation drying process, the convective or the hot air drying process, the low pressure or the vacuum drying process, the microwave or the electromagnetic drying process, the heat pump drying, the fluidized bed drying, or a combination thereof.

24. The method of claim 17, wherein step a) the pins (206) have the ratio of the distance between each pin to the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 3 to 60

25. The method of claim 17, wherein step a) the pins (206) can be arranged onto the surface of the shaft (202) in a manner that can be selected from a circular, a helix, or a random pattern. The method of claim 17, wherein step a) the number of pins (206) per loop ranges from 2 to 16 pins. The method of claim 26, wherein step a) the number of pins (206) per loop ranges from 4 to 12 pins. The method of claim 17, wherein step a) the pins (206) have the pitch distance in the range of 4 to 20 centimeters. The method of claim 28, wherein step a) the pins (206) have the pitch distance in the range of 6 to 12 centimeters. The method of claim 17, wherein step a) the pins (206) have the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 0.2 to 3 centimeters. The method of claim 30, wherein step a) the pins (206) have the distance between the tip of the pin (206) to the wall of mixing chamber (108) in the range of 0.2 to 2 centimeters. The method of claim 17, wherein step a) the pins (206) can be in the shape seleced from cylinder or polyhedron. The method of claim 17, wherein step a) the mixing chamber (108) can be in the shape seleced from cylinder, cubic, polyhedron, or similar geometry. The process of claim 17, wherein step a) the mixing chamber (108) is a longitudinal cylinder where the latex and a filler are fed through inlets located on the top and the latex composition is conveyed through an outlet located at the bottom of the mixing chamber (108) to accommodate the continuous mixing process. The process of claim 17, wherein step a) the mixing chamber (108) has the length in the range of 300 to 4,000 centimeters. The process of claim 35, wherein step a) the mixing chamber (108) has the length in the range of 500 to 3,000 centimeters. The process of claim 17, wherein step a) the latex feeding control unit (104) is a pump. The process of claim 17, wherein step a) the filler feeding control unit (107) is conveying equipment that can be selected from a belt conveyor or a screw conveyor