Title of Invention	A METHOD FOR PRODUCING CHLORINATED RUBBER AND AN APPARATUS THEREFOR
Abstract	ABSTRACT OF THE DISCLOSURE The present invention provides a production method of a chlorinated rubber wherein an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion is dried in the fluidized drying with a drying medium to obtain a preliminary dried powders, and the preliminary dried powders are dried in the fluidized drying again, and an apparatus therefor. According to the present invention, a high quality chlorinated rubber can be obtained efficiently with easy handling from an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion.

Title of Invention

A METHOD FOR PRODUCING CHLORINATED RUBBER AND AN APPARATUS THEREFOR

Abstract

ABSTRACT OF THE DISCLOSURE The present invention provides a production method of a chlorinated rubber wherein an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion is dried in the fluidized drying with a drying medium to obtain a preliminary dried powders, and the preliminary dried powders are dried in the fluidized drying again, and an apparatus therefor. According to the present invention, a high quality chlorinated rubber can be obtained efficiently with easy handling from an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion.

Full Text	BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method for producing a chlorinated rubber and an apparatus therefor. More specifically, it relates to a method of efficiently producing a chlorinated rubber from a chlorinated rubber cake obtained by chlorinating an acidic or highly acidic rubber latex while maintaining a high quality, and an apparatus therefor. Description of the Related Art Since a chlorinated rubber obtained by chlorinating a natural rubber or a polyisoprene rubber such as a synthetic isoprene is excellent in terms of acid resistance, alkaline resistance, chemical resistance, flame resistance and conductivity and has a film formation ability, it is used in a varnish, a paint, a vehicle for a printing ink, a wrapping film, and an adhesive. In particular, a highly chlorinated product having a 55% by weight or more of chlorine content is broadly used as a material for an anti-corrosion paint having an excellent drying property. Conventionally, as a method for chlorinating a polyisoprene rubber, a method of obtaining powders by dissolving a polyisoprene rubber in a chlorinated hydrocarbon solvent, blowing a chlorine gas for reaction, and evaporating the chlorinated hydrocarbon by the spray dry method is known. The method is widely used since it can chlorinate a polyisoprene rubber homogeneously and obtain a highly chlorinated rubber soluble in an organic solvent. However, /in view of the recent movement for the earth environment conservation, the use of a chlorinated hydrocarbon solvent (carbon tetrachloride) is expected to be limited. Then development of a method of dispersing a polyisoprene rubber in an agueous medium for chlorination is called for. Accordingly, the present inventors proposed a technology for obtaining a chlorinated rubber by supplying a chlorine gas to a highly acidic aqueous rubber latex as disclosed in Japanese Patent Laid-Open No. 5-202101. The chlorination method disclosed in Japanese Patent Laid-Open No. 5-202101 is a method of blowing a chlorine gas into a polyisoprene-containing highly acidic aqueous rubber latex, more specifically, it is a method of placing hydrochloric acid of a high concentration in a reaction vessel, cooling, introducing chlorine while stirring under an ultraviolet ray irradiation, and dropping a polyisoprene rubber latex with a surfactant dispersed therein for chlorination. However, it was found that a chlorinated rubber slurry obtained by the chlorination method has characteristics unlike previous ones. That is, since it can easily adhere to the wall portion of a drying device when drying a chlorinated rubber cake obtained by filtrating the chlorinated rubber slurry, it can easily form a large agglomerate, and thus the drying efficiency in a conventional drying method is extremely poor. For example, an pneumatic drier is used for drying cake-like powders, but since the above-mentioned chlorinated rubber cake adheres to the wall portion, it cannot be applied with a drying air flow. In the case where a chlorinated rubber is utilized for an ink, a paint, or an adhesive, the molecular weight thereof needs to be controlled, however, there is a risk of molecular weight change unless the production process of the chlorinated rubber cake is finished in a short duration. Further, in order to prepare a chlorinated rubber cake from a chlorinated rubber slurry, for example, a centrifugal separator is used. However, since a chlorinated rubber obtained by the above-mentioned method is extremely small particles, the filtration property becomes poor remarkably with a cake accumulated in the centrifugal separator of about 30 mm or more thickness so that a long time operation is required for one cycle including washing with water, and thus the molecular weight change is liable. The water content of the chlorinated rubber cake needs to be adjusted within 45 to 65% since the cake becomes hard with a 40% or less water content. Further, since a chlorinated rubber slurry is collected from a highly acidic aqueous medium, it limits the material of the centrifugal separator. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of producing a high quality chlorinated rubber from an acidic or highly acidic chlorinated rubber cake obtained by chlorinating a rubber latex or a water dispersion thereof efficiently with easy handling, and an apparatus therefor. The present inventors studied elaborately to solve the above-mentioned problems. That is, the present invention provides a method for producing a chlorinated rubber comprising fluidized drying an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion with a drying medium to obtain preliminary dried powders, and fluidized drying again the preliminary dried powders. Further, the present invention provides an apparatus for producing a chlorinated rubber equipped with an (A) unit comprising a fluidized drying means using a medium (hereinafter referred to as "medium fluidized drying means") with a supply opening for a chlorinated rubber cake, and containing a drying medium in its inside, a bag filter connected with the medium fluidized drying means via a conduit, and a fluidized drying means provided downstream of the bag filter. Furthermore, the present invention provides an apparatus for producing the chlorinated rubber, comprising a (B) unit upstream of the (A) unit, the (B) unit being an apparatus for producing a chlorinated rubber cake from a chlorinated rubber slurry obtained after chlorinating a rubber latex or an aqueous dispersion, comprising: a belt filter movable in the horizontal direction, and a means for absorbing water contained in the chlorinated rubber slurry via the belt filter. Still further, the present invention provides an apparatus for producing the chlorinated rubber comprising the (B) unit upstream of the (A) unit, and further comprising a (C) unit upstream of the (B) unit, the (C) unit being an apparatus for producing a chlorinated rubber slurry obtained by chlorinating a rubber latex or an aqueous dispersion, comprising: a reaction vessel for accommodating the reaction liquid, provided with an outlet portion for the reaction liquid, a circulating line for guiding the reaction liquid from the outlet portion to the outside of the reaction vessel, and returning to the reaction vessel, a heat exchanger provided at least one point in the circulating line, and a UV lamp provided in the reaction vessel and/or the circulating line. ACCOMPANYING BRIEF DESCRIPTION OF THE/DRAWINGS Fig. 1 is a diagram for explaining one embodiment of the apparatus of the present invention. Fig. 2 is a diagram for explaining an apparatus, which can be preferably connected with the apparatus of the present invention. Fig. 3 is a diagram for explaining an apparatus, which can be preferably connected with the apparatus of the present invention. Fig. 4 is a diagram for explaining a UV lamp, which can be preferably used in the apparatus of Fig. 3. Figs. 5 to 7 are diagrams for explaining apparatus, which can be preferably connected with the apparatus of the present invention. Fig. 8 is a diagram for explaining one embodiment of the apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION Hereinafter the present invention will be explained in detail with reference to the accompanied drawings. Fig. 1 is a diagram for explaining one embodiment of the apparatus of the present invention. The apparatus 1 of the present invention comprises a medium fluidized drying means 2, a bag filter 3, and a fluidized drying means 4. The medium fluidized drying means 2 is provided with a hot air supply opening 10 at the bottom portion for supplying hot air for drying. A flat perforated plate 6 and drying medium 7 thereon are provided downstream of the hot air supply opening 10. The drying medium in this embodiment is shown as medium balls 7. A large number of the medium balls 7, which have a diameter of 2 to 5 mm, are placed on the flat perforated plate 6 to the thickness of about 50 to 300 mm. As a material for the medium balls, a large one is not preferable since it may come in contact with chlorine or hydrochloric acid, and it is expected to flow. Further, one having a specific gravity similar to that of a chlorinated rubber cake is not also preferable. In view of these elements, the diameter of the medium balls 7 is preferably 2 to 5 mm as mentioned above, and a material is preferably alumina, silicon nitride, quartz, and the like. The flat perforated plate 6 allows the passage of hot air, but does not allow the passage of the medium balls. A supply opening 5 for a chlorinated rubber cake is provided in the medium fluidized drying means 2 so that the chlorinated rubber cake obtained by chlorinating an acidic highly acidic rubber latex is introduced therefrom. The introduced chlorinated rubber cake is dried according to the fluid motion of the medium balls 7 by the hot air to become powdery, and blown up to the upper part of the medium fluidized drying means 2, The temperature of the hot air is, for example, 50 to 130°C , preferably 70 to 100°C . According to the temperature range, the drying efficiency is improved, deterioration of the chlorinated rubber cake powders can be prevented, and further, adhesion and re-agglomeration of the powders can be restrained. By the medium fluidized drying means 2, most of the water contained in the chlorinated rubber cake can be eliminated so as to provide a wet powder. The wet powder (powders of a chlorinated rubber) blown up to the upper part of the medium fluidized drying means 2 reaches a conduit 8. The conduit 8 is made from a material with a diameter and a length not preventing the passage of the powders of the chlorinated rubber. For example, it can be made from stainless steel, a fluororesin-coated material, and the like, with a 300 to 1,000 mm diameter and a 3 to 15 mm length. The conduit 8 is connected with the bag filter 3 at the end. The bag filter 3 can be a known type comprising a plurality of cylindrical filter cloths. The powders of the chlorinated rubber passed through the conduit 8 contact with the bag filter 3, and are dropped to the fluidized drying means 4 at the lower part. Powders adhered to the bag filter 3 are blown away by compressed high pressure air supplied from a pulse air generator 9 provided above the bag filter 3 at appropriate intervals so as to reach the flow drying means 4. The fluidized drying means 4 is provided below the , bag filter 3 for finishing the powders of the chlorinated rubber. A hot air supply opening 11 is provided at the bottom of the fluidized drying means 4 for supplying hot air for drying. A flat perforated plate 12 is provided downstream of the hot air supply opening 11. It is preferable that the flat perforated plate 12 does not allow the powders easily. The powders flow by the hot air blown from the hole portion of the flat perforated plate 12, are dried for finishing, and pass through a rotor valve 13 so as to be discharged from the powder output opening 14. A preferable temperature of the hot air in the flow drying means 4 is, for example, 60 to 100°C . A preferable production embodiment of the chlorinated rubber cake to be used is as described below. Fig. 2 is a diagram for explaining an apparatus, which can be preferably connected with the apparatus 1 of the present invention. An apparatus 21 has a belt filter 22 of a ring shape formed with four rolls 30, 31, 32 and 33. The material of the belt filter 22 is not particularly limited as long as it does not allow the passage of fine particles of a chlorinated rubber but allow the passage of water. Examples thereof include a filter cloth. The belt filter 22 can be moved in the horizontal direction by the filter cloth driving roll 30. An aqueous chlorinated rubber slurry is supplied on the belt filter 22. The supply amount of the chlorinated rubber slurry can be determined according to the size of the apparatus, the chlorination conditions, and the like. For example, it is preferable that it is supplied on the belt filter 22 by 5 to 25 ram thickness, most preferably by 20 mm or less thickness. The belt filter 22 is moved in the horizontal direction by the filter cloth moving roll 30 to reach the position where means for absorbing the water contained in the chlorinated rubber slurry (flat perforated plates 23) are provided therebelow. The belt filter 22 stops at the position for water absorption of the chlorinated rubber slurry. According to the embodiment of Fig. 2, a chlorinated rubber cake of the present invention can be obtained by absorbing the water in the chlorinated rubber slurry from the dishes 23 provided at two positions, which are interlocked to a vacuum system via a tank 27 through the belt filter 22 by reducing the pressure. The pressure reduction can be easily started or stopped by a valve 25. The absorbed water can be accommodated by the tank 27 so that it can be reused as needed. Accordingly, the water content of the chlorinated rubber cake can be adjusted at, for example, 45 to 60%. The pressure reduction time is preferably 15 to 150 seconds in view of the quality. It is preferable that the chlorinated rubber cake after water absorption is moved with the belt filter 22 in a predetermined distance in the horizontal direction so as to be washed with water thereat. It is preferable that the temperature of the washing water is 50°C or higher in view of the filtration speed. As mentioned above, the belt filter 22 is stopped at a position where the washing water is supplied so that the washing water is supplied from a position above the belt filter 22, and the water is absorbed. According to the embodiment of Fig. 2, dishes 24, which are connected to a vacuum system via a tank 28, are provided at two positions. The pressure reduction can be easily started or stopped by a valve 26. The absorbed water can be accommodated by the tank 28 so that it can be reused as needed. After the water ^ absorption process, the valves 25, 26 are shut out so that the dishes 23, 24 return to an ordinary pressure, with the belt filter 22 moved for absorbing the water in a supplied chlorinated rubber slurry as mentioned above. Accordingly, it is preferable that the filter cloth driving roll 30, the valve 25 and the valve 26 are interlocked. The adjusted chlorinated rubber cake moved with the belt filter 22 is dropped from the roll 33 to a cake receptacle 34. The chlorinated rubber cake obtained accordingly can be supplied to the apparatus shown in Fig. 1 for drying. The above-mentioned production method of a chlorinated rubber slurry is not particularly limited. For example, an apparatus disclosed in Japanese Patent Laid-Open No. 5-202101 can be used. However, since a large amount of heat is generated by reaction or dilution, the reaction liquid has a thixotropy property so that a remarkably long reaction time is needed in dealing with a large amount, and the chlorine utilization efficiency is poor and foam generation by the surfactant in the reaction liquid prevents the liquid transfer or washing according to the apparatus, sometimes it is not appropriate for a mass production. Accordingly, it is preferable to produce a chlorinated rubber slurry by the below-mentioned apparatus. That is, the preferable apparatus is an apparatus for producing a chlorinated rubber slurry from a reaction liquid obtained by chlorinating a rubber latex or an aqueous dispersion, comprising: a reaction vessel for accommodating the reaction liquid, provided with an outlet portion for the reaction liquid, a circulating line for guiding the reaction liquid from the outlet portion to the outside of the reaction vessel, and returning to the reaction vessel, a heat exchanger provided at least one point in the circulating line, and a UV lamp provided in the reaction vessel and/or the circulating line. In Japanese Patent Laid-Open No. 5-202101, since the chlorination immediately occurs so that the heat generation in the reaction substantially finishes in several hours from starting the chlorination, a great amount of heat needs to be eliminated in a short time. According to the present invention, the reaction heat can be eliminated efficiently in a large amount, since a circulating line is provided outside the reaction vessel so as to circulate the reaction liquid and further, a heat exchanger is provided in the circulating line. The reaction vessel needs to accommodate a highly acidic aqueous dispersion of a polyisoprene rubber and a chlorine gas (hereinafter referred to as a reaction liquid) without corrosion. As a material thereof, a glass lining can be presented. Further, it is preferable that the reaction vessel can have a 500 to 30,000 liter capacity, with a stirring means provided inside. The reaction vessel is provided with an outlet portion, with the circulating line connected thereto. The position of the outlet portion of the reaction vessel can be optionally selected, but it is preferable to locate it, for example, at the bottom part of the reaction vessel so as not to prevent the homogeneous mixing of the reaction liquid in the reaction vessel. The length of the circulating line needs to be determined according to the size of the reaction vessel, the chlorination degree, and the line, however, it is, in general, 5 to 30 m. The shape of the circulating line is not particularly limited as long as the heat elimination effect is not disturbed and it is appropriate for locating a heat exchanger. In the case where the circulating line is pipe¬like, the diameter thereof is, for example, about 4 to 40 cm. The material of the circulating line needs to be not corrosive with respect to the reaction liquid, it is, for example, a glass lining. The reaction liquid in the reaction vessel flows into the circulating line from the outlet portion of the reaction vessel by the function of a pump, and the like so as to flow in the circulating line. By the flow of the reaction liquid in the circulating line, the reaction heat is discharged to the outside. The flow rate of the reaction liquid can be optionally selected according to the length and the shape of the circulating line, the chlorination degree, and the like, but it is, for example, 0.1 to 10 m3/min. The circulating line starts from the outlet portion of the reaction vessel and returns to the reaction vessel. The finishing point of the circulating line is preferably at a position far from the outlet of the reaction vessel, and soaked in the liquid. Although the reaction liquid has a thixotropy property, since it flows in the circulating line, the flowability of the reaction liquid is improved so that the extension of the reaction time can be restrained. The heat exchanger is provided at least at one point in the circulating line for further improving the heat eliminating effect. A heat exchanger of a known type can be used. Examples thereof include a tube type heat exchanger and a plate type heat exchanger, which are commercially available. Furthermore, it is preferable to provide one or a plurality of a static mixer in the circulating line. The configuration enhances the chlorine gas dispersion so that the chlorine utilization efficiency is improved, the chlorination rate is increased, and the foam formation by the surfactant in the reaction liquid can be restrained. It is well known that a static mixer is an in-line stirrer without a driving portion where right-handed and left-handed spiral elements are provided alternately with the end of an element provided perpendicular to the end of adjacent elements, capable of efficiently mixing liquid, gas and flowable solid. Further, since the energy necessary for mixing corresponds with the pressure loss at the time the fluid passes through the mixer, the amount of the energy consumption is small. The number of the elements is optional, but it can be, for example, 4 to 24 pieces. A chlorinated rubber is produced with the ultraviolet ray irradiation to the reaction liquid. The ultraviolet ray irradiation can be conducted by, for example, providing a UV lamp in the reaction vessel and/or the circulating line for improving the efficiency. It is confirmed that the chlorination can proceed smoothly with a UV lamp provided at either position, but it is preferable to provide it in the reaction vessel. Although the reaction rate is facilitated by enforcing the ultraviolet ray irradiation intensity, the reaction heat rises accordingly. Therefore, the ultraviolet ray irradiation intensity can be optionally selected in consideration of these factors. Further, in the case where a UV lamp is provided in the circulating line, it is preferable to determine the size and the position of the UV lamp in consideration of the flow rate of the reaction liquid, the number of circulation, and the ability of the circulation pump. As shown in Fig. 4, it is preferable that the UV lamp has a double structure for cooling the heat generated at the mercury lamp by cooling water where starting and stopping is controlled automatically for ensuring security. At the time of operation, it is preferable, for example, to place an acid aqueous solution of a high concentration in the reaction vessel, introduce a saturated amount of a chlorine gas into the circulating line where the solution is circulated by a pump for sufficient mixing and dissolving, and then slowly inject an aqueous dispersion of a polyisoprene rubber thereto, while blowing a chlorine gas, considering the chlorine gas supply amount sufficient for reaction with the UV lamp on. It is preferable that the chlorine gas and the aqueous dispersion are introduced from the upstream side of the static mixer. The polyisoprene rubber to be used is a polymer containing an isoprene unit in a molecular chain as the main component. Concrete examples thereof include a natural rubber, a synthetic polyisoprene, or copolymers of isoprene and a monomer having a hydrophilic group, such as a hydroxyl group, a carboxyl group, and an amide group, copolymers of isoprene and a vinyl monomer such as (meth)acrylate, copolymers of isoprene and another diene type monomer such as butadiene, grafted polyisoprene obtained by grafting maleic acid, maleic anhydride, or succinic acid. These can be used alone or in combination of two or more. The average particle size of a polyisoprene rubber in an aqueous dispersion is, in general, 100 ^ m or less, preferably 20 // m or less, more preferably 1 ^ m or less. An excessively large average particle size prevent homogeneous chlorination so that it generates unevenness in the solubility with respect to an organic solvent such as toluene, to generate partially-undissolved part. Examples of acids used for a high concentration aqueous solution of an acid include strong acids such as hydrochloric acid, sulfuric acid, and nitric acid. Among these examples, hydrochloric acid or a combination of hydrochloric acid and sulfuric acid or nitric acid is preferable in terms of smoothly conducting the chlorination process. The concentration of the acid in the high concentration aqueous solution of an acid is, in general, 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more. In the case where a natural rubber latex is used, a high chlorination can be achieved without rubber particle agglomeration with an acid concentration of 2% by weight or more, preferably 5% by weight or more under the presence of a surfactant described below. The upper limit of the acid concentration is in general, 40% by weight, preferably about 36% by weight In the case where an aqueous dispersion of a polyisoprene rubber and a high concentration aqueous solution of an acid are mixed, the concentration of the polyisoprene rubber at the time of starting the chlorination reaction is, in general, 1% by weight or more, preferably about 2 to 10% by weight. A lower polymer concentration in the highly acidic aqueous dispersion is preferable in order to control the chlorination reaction, but in view of the balance with productivity, 2 to 10% by weight is appropriate. Furthermore, with the polymer concentration range, a highly acidic condition can be stably maintained. In the case where an aqueous dispersion of a polyisoprene rubber and a high concentration aqueous solution of an acid are mixed, it is preferable that a surfactant exists in order to improve the dispersion of the rubber fine particles. However, in the case where the aqueous dispersion of the polyisoprene rubber contains the surfactant, addition of the surfactant is not needed. As a surfactant, a nonionic surfactant, an anionic surfactant, a mixture thereof, and a nonionic-anionic surfactant, which do not degenerate by an acid can be preferably used. To a natural rubber latex, a nonionic or nonionic-anionic surfactant is extremely preferable for preventing agglomeration. Examples of nonionic surfactants include a condensed product of polyoxyethylene polyoxypropylene, polyoxyalkylene alkylether, polyoxyalkylene nonylphenolether, sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, and polyoxyalkylene glycerin fatty acid ester. Among these examples, those having an HLB (hydrophile-liphophile balance) of 8 or more are preferable. Examples of anionic surfactants include higher alcohol sulfate, alkyl benzene sulfonic acid salt, alkyl phosphate salt, polyoxyalkylene sulfate, and dialkyl sulfosuccinic acid salt. However, higher fatty acid soap and the like, which can easily degenerate by acids, are not preferable. Examples of nonionic-anionic surfactants include polyoxyethylene alkyl ether sodium sulfate, and polyoxyethylene alkyl aryl ether sodium sulfate. The amount of the surfactant is preferably at the minimum level where the dispersion stability of a highly acidic aqueous dispersion of a polyisoprene rubber can be ensured. In general, it is 15 parts by weight or less with respect to 100 parts by weight of the polyisoprene rubber, preferably 0.1 to 10 parts by weight, more preferably 1 to 7 parts by weight. An excessively large ratio of the surfactant may affect on the chlorination. The reaction temperature is preferably in the range of 0 to 90°C . With a temperature lower than 0°C , a problem of freezing of the medium may generate, on the other hand, with a temperature higher than 90°C , rubber particles can easily adhere to each other. It is preferable that the temperature is kept at a low temperature of about 40°C or less in the initial stage of the chlorination reaction and is raised in the later stage. The reaction time partly depends on the chlorination degree, but in general, it is about 2 to 20 hours. The chlorine gas can be supplied either by the feed type or the sealed type, and further, either in an ordinary pressure or under load. The chlorination degree can be determined optionally as needed. But in general, chlorination is conducted until the chlorine concentration (chlorine amount) in the chlorine rubber becomes in the range of 55 to 75% by weight. With an excessively low chlorine concentration, an obtained chlorinated rubber cannot dissolve in an organic solvent such as toluene easily to deteriorate the compatibility with a plasticizer or another resin. On the other hand, with an excessively large chlorine concentration, the chlorinated rubber cannot dissolve in an organic solvent easily. A radical initializer or another additive can be added as needed at the time of chlorination. The viscosity of a chlorinated rubber in an organic solvent can be optionally selected by introducing a catalysis, air, an oxide, and the like at the time of chlorination and adjusting the introduction amount. A preferable embodiment of the present invention is that a chlorinated rubber slurry obtained accordingly is processed to be a chlorinated rubber cake by the apparatus shown in Fig. 2, and is dried by the apparatus shown in Fig. 1. A further preferable embodiment is that, as shown in Fig. 8, the apparatus are interlocked and automatically operated. EXAMPLES Hereinafter the present invention will be further described with reference to examples and comparative examples. Production Example 1 of a Chlorinated Rubber Slurry A chlorinated rubber slurry was produced with an apparatus shown in Fig. 3. An apparatus 41 of Fig. 3 comprises a 500-liter cylindrical reaction vessel 42 provided with a stirrer 52, a thermometer 53, a UV lamp 54 (a high pressure mercury lamp having a configuration of Fig. 4, produced by Toshiba Lightec Corp.), having an outlet portion at the lower part; a pipe¬like circulating line 44 having 10 m length and 5 cm diameter, starting from the outlet portion 43 of the reaction vessel 42, for circulating the reaction liquid, and a heat exchanger 45 (tube type heat exchanger produced by Le Carbon Corp.) at one point of the circulating line. The circulating line 44 is provided with a chlorine gas injecting opening 46, a latex injecting opening 47, and an injecting pump (not illustrated) are provided. A circulating pump 48 is provided between the reaction vessel 42 and the chlorine gas injecting opening 46. 444 kg of 35% by weight of hydrochloric acid was placed in the reaction vessel. The circulating pump was operated while stirring the hydrochloric acid with a stirrer at 107 rpm so as to circulate the hydrochloric acid from the outlet portion into the circulating line at a rate of 10 m3/hour. The temperature of the circulating hydrochloric acid was maintained at 10°C or lower with a chlorine gas injected into the circulating line at a rate of 9.6 kg/hour and dissolved. 2.5 kg of polyoxyalkylene nonyl phenol ether (solid component concentration: 10% by weight) and 11.8 kg of pure water were added to 41.7 kg of a natural rubber latex preliminarily stabilized by a low ammonia treatment (solid component concentration: 60%), and mixed homogeneously to prepare an aqueous dispersion (solid component concentration: 45% by weight). 56.0 kg of the aqueous dispersion was injected from the latex injecting opening of the circulating line over 4 hours with the UV lamp on and the temperature of the reaction vessel maintained at 30°C . Then 71.3 kg of a chlorine gas and 200 1 of oxygen were introduced from the chlorine gas injecting opening 46 over 14 hours with the temperature in the apparatus maintained at 20 to 30°C . The dispersion state of the particles was extremely good during the chlorination. After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 65% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 20 cps/25°C . Production Example 2 of a Chlorinated Rubber Slurry With the apparatus and the process same as production example 1, a chlorinated rubber slurry was produced. However, the UV lamp 54 was placed in the circulating line 44 as shown in Fig. 5. As a result, the dispersion state of the particles was extremely good during the chlorination. After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 65% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 21 cps/25°C . Production Example 3 of a Chlorinated Rubber Slurry With the apparatus and the process same as production example 1, a chlorinated rubber slurry was produced. However, static mixers 49 were provided at two points, that is, between the chlorine gas injecting opening 46 and the latex injecting opening 47, and between the latex injecting opening 47 and the heat exchanger 45 as shown in Fig. 6. Further, 80.1 kg of the chlorine gas and 200 1 of oxygen were introduced from the injecting opening 46 provided upstream of the static mixer over 14 hours. As a result, the dispersion state of the particles was extremely good during the chlorination. After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 17 cps/25°C . Production Example 4 of a Chlorinated Rubber Slurry With the apparatus and the process the same as production example 3, a chlorinated rubber slurry was produced. However, the UV lamp 54 was placed in the circulating line 44 as shown in Fig. 7. Further, 81.0 kg of the chlorine gas and 200 1 of oxygen were introduced from the injecting opening 46 provided upstream of the static mixer over 14 hours. As a result, the dispersion state of the particles was extremely good during the chlorination. After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 21 cps/25°C . Production Example 5 of a Chlorinated Rubber Slurry The production example 3 was repeated except that 40 1 of oxygen was used. As a result, the dispersion state of the particles was extremely good during the chlorination. After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 150 cps/25°C . Production Example 6 of a Chlorinated Rubber Slurry The production example 4 was repeated except that 38 1 of oxygen was used. As a result, the dispersion state of the particles was extremely good during the chlorination. After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 160 cps/25°C . Production Example of a Chlorinated Rubber Cake Chlorinated rubber cakes were produced from the chlorinated rubber slurries prepared, in production examples 1 to 6 with the apparatus shown in Fig. 2. The slurry containing 12% of a chlorinated rubber after the chlorination reaction (before drying) was supplied at a rate of 500 kg/hour onto a horizontally-movable filter cloth in production examples 1 to 6. The moving rate of the filter cloth was set at 3 seconds in 40 seconds. Therefore, the pressure reduction time was 37 seconds where the thickness of the chlorinated rubber slurry was controlled to be 8 to 11 mm. Then the filter cloth was moved horizontally by 200 cm where washing water of 70°C was supplied onto the chlorinated rubber slurry at a rate of 750 kg/hour for water absorption. After about 40 minutes, discharge of a chlorinated rubber cake was started onto a cake receptacle. The water content of the obtained chlorinated rubber cake was 55%, which allows easy mechanical flow. Example 1 The present invention was implemented with the apparatus of Fig. 1. The apparatus (Fig. 3, 5 to 7) used in production examples 1 to 4 of a chlorinated rubber slurry, the apparatus (Fig. 2) used in production example of a chlorinated rubber cake, and the apparatus of Fig. 1 were interlocked with an ordinary method. Hot air of 80°C was provided from the hot air blowing opening 10 such that the medium balls 7 can sufficiently move. The chlorinated rubber cake having a 55% water content obtained in production example of the chlorinated rubber cake (the cake was obtained from the production example 1 slurry) was introduced from the chlorinated rubber cake supply opening 5 at a rate of 60 kg/hour into the medium fluidized drying means 2 to obtain a wet powder (powders of a chlorinated rubber). The powders after passing through the conduit 8 came in contact with the bag filter 3, and reached the fluidized drying means 4 at the downstream side. The powders adhered to the bag filter 3 were blown away by the pulse air from the pulse air generator 9, which is operated for 0.5 second with an interval of 30 seconds. Hot air of 80°C from the hot air blowing opening 11 at the bottom part of the fluidized drying means 4 passed through the flat perforated plate 12 to further dry the powders. The powders were finally obtained from the powder output opening 14 through the rotary valve 13 at a rate of about 26 kg/hour. The water content of the obtained powders was 0.2% or less. The time required from the input of the chlorinated rubber cake to the powder output opening 14 was about 1 hour. The viscosity of a 20% toluene solution of the final powders obtained in this example was 18 cp, which was always constant. Next, the Example 1 was repeated except that the chlorinated rubber slurry was changed to those obtained by the production examples 2 to 6. The same results were obtained. Further, The viscosity of a 20% toluene solution of the final powders obtained from the production examples 2 to 6 slurries were 19, 15, 19, 135 and 144 cp, respectively, which was always constant. Comparative Example 1 A block of 20 kg of the chlorinated rubber cake having a 55% water content same as example 1 (the cake was obtained from the production example 1 slurry) formed by hands was placed in a shelf type drier to introduce hot air from the lower part where three plates of 30 mm height, 600 mm length and 1,000 mm width can be set. Then hot air of 120 to 130°C was introduced for 2 hours. The water content of the cake was 15% then. After pulverization, it was placed again in the drier to be dried for 4 hours while introducing hot air of 100°C from the lower part to obtain a chlorinated rubber of a 0.3% water content. The viscosity of a 20% toluene solution thereof was irregular in the range of 12 to 17 cp depending on the sampling parts. Next, the Comparative Example 1 was repeated except that the chlorinated rubber slurry was changed to those obtained by the production examples 2 to 4. The same results were obtained. Further, the Comparative Example 1 was repeated except that the chlorinated rubber slurry was changed to those obtained by the production examples 5 and 6. The viscosity of a 20% toluene solution thereof was irregular in the range of 90 to 120 cp depending on the sampling parts. According to the present invention, since a chlorinated rubber cake is fluidized-dried with a drying medium, most of the water content in the cake can be eliminated without adhesion to the wall portion of the drier. Further, since it is applied with finishing-drying by fluidized-drying again, the viscosity change of the chlorinated rubber can be restrained. Besides, since the powders finally obtained have an appropriate particle size, it is easy to handle. Furthermore, since the method of the present invention allows to have a drying process at a temperature lower than conventional ones, the material of the drier can be selected in a wider range. That is, according to the present invention, a method of obtaining a high quality chlorinated rubber efficiently with easy handling from an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion, and an apparatus therefor can be provided. A chlorinated rubber can be obtained further efficiently in combination with the production apparatus of a chlorinated rubber slurry and/or the production apparatus of a chlorinated rubber cake as described above. 1. A method for producing a chlorinated rubber comprising: fluidized drying an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion with a drying medium to obtain a preliminary dried powders; and fluidized drying again the preliminary dried powders . 2. The method according to claim 1, wherein the temperature of the fluidized drying with the drying medium is 50 to 130°C . 3. The method according to claim 2, wherein the drying medium is medium balls having a 2 to 5 mm diameter. 4. The method according to claim 1, wherein the chlorinated rubber cake is obtained by supplying an acidic or highly acidic chlorinated rubber slurry after chlorinating the rubber latex or the aqueous dispersion onto a horizontally- movable belt filter, and absorbing water contained in the chlorinated rubber slurry. 5. The method according to claim 1, wherein the chlorinated rubber slurry is obtained by taking the acidic or highly acidic latex or aqueous dispersion of the rubber in a reaction vessel outside the reaction vessel by a circulating line so that a chlorine gas is blown to the latex or the dispersion for chlorination while eliminating the generated heat of the latex or the aqueous dispersion by a heat exchanger. 6. An apparatus for producing a chlorinated rubber equipped with a first unit comprising: a fluidized drying means using a medium with a supply opening for a chlorinated rubber cake, and drying medium in the inside; a bag filter connected with the fluidized medium drying means via a conduit; and a fluidized drying means provided downstream of the bag filter. 7. The apparatus according to claim 6, comprising a second unit upstream of the first unit, said second unit being an apparatus for producing the chlorinated rubber cake from a chlorinated rubber slurry obtained after chlorinating a rubber latex or an aqueous dispersion, comprising: a belt filter movable in the horizontal direction; and a means for suctioning water contained in the chlorinated rubber slurry via the belt filter. 8. The apparatus according to claim 7, wherein third unit upstream of said second unit, said third unit being an apparatus for producing the chlorinated rubber slurry obtained by chlorinating a rubber latex or an aqueous dispersion, comprising: a reaction vessel for accommodating the reaction liquid, provided with an outlet portion for the reaction liquid, a circulating line for guiding the reaction liquid from the outlet portion to outside of the reaction vessel, and returning it back to the reaction vessel, a heat exchanger provided at at least one point in the circulating line, and a UV lamp provided in the reaction vessel and/or the circulating line. 9. A method for producing a chlorinated rubber substantially as herein described with reference to the accompanying drawings. 10. An apparatus for producing a chlorinated rubber substantially as herein described with reference to the accompanying drawings.

Full Text

BACKGROUND OF THE INVENTION Field of the Invention
The present invention relates to a method for producing a chlorinated rubber and an apparatus therefor. More specifically, it relates to a method of efficiently producing a chlorinated rubber from a chlorinated rubber cake obtained by chlorinating an acidic or highly acidic rubber latex while maintaining a high quality, and an apparatus therefor.
Description of the Related Art
Since a chlorinated rubber obtained by chlorinating a natural rubber or a polyisoprene rubber such as a synthetic isoprene is excellent in terms of acid resistance, alkaline resistance, chemical resistance, flame resistance and conductivity and has a film formation ability, it is used in a varnish, a paint, a vehicle for a printing ink, a wrapping film, and an adhesive. In particular, a highly chlorinated product having a 55% by weight or more of chlorine content is broadly used as a material for an anti-corrosion paint having an excellent drying property.
Conventionally, as a method for chlorinating a polyisoprene rubber, a method of obtaining powders by dissolving a polyisoprene rubber in a chlorinated hydrocarbon solvent, blowing a chlorine gas for reaction, and evaporating the chlorinated hydrocarbon by the spray dry method is known. The method is widely used since it can chlorinate a

polyisoprene rubber homogeneously and obtain a highly chlorinated rubber soluble in an organic solvent. However, /in view of the recent movement for the earth environment conservation, the use of a chlorinated hydrocarbon solvent (carbon tetrachloride) is expected to be limited.
Then development of a method of dispersing a polyisoprene rubber in an agueous medium for chlorination is called for. Accordingly, the present inventors proposed a technology for obtaining a chlorinated rubber by supplying a chlorine gas to a highly acidic aqueous rubber latex as disclosed in Japanese Patent Laid-Open No. 5-202101.
The chlorination method disclosed in Japanese Patent Laid-Open No. 5-202101 is a method of blowing a chlorine gas into a polyisoprene-containing highly acidic aqueous rubber latex, more specifically, it is a method of placing hydrochloric acid of a high concentration in a reaction vessel, cooling, introducing chlorine while stirring under an ultraviolet ray irradiation, and dropping a polyisoprene rubber latex with a surfactant dispersed therein for chlorination.
However, it was found that a chlorinated rubber slurry obtained by the chlorination method has characteristics unlike previous ones. That is, since it can easily adhere to the wall portion of a drying device when drying a chlorinated rubber cake obtained by filtrating the chlorinated rubber slurry, it can easily form a large agglomerate, and thus the drying efficiency in a conventional drying method is extremely poor. For example, an pneumatic drier is used for drying cake-like powders, but since the above-mentioned chlorinated rubber cake adheres to the wall portion, it cannot be applied

with a drying air flow.
In the case where a chlorinated rubber is utilized for an ink, a paint, or an adhesive, the molecular weight thereof needs to be controlled, however, there is a risk of molecular weight change unless the production process of the chlorinated rubber cake is finished in a short duration.
Further, in order to prepare a chlorinated rubber cake from a chlorinated rubber slurry, for example, a centrifugal separator is used. However, since a chlorinated rubber obtained by the above-mentioned method is extremely small particles, the filtration property becomes poor remarkably with a cake accumulated in the centrifugal separator of about 30 mm or more thickness so that a long time operation is required for one cycle including washing with water, and thus the molecular weight change is liable. The water content of the chlorinated rubber cake needs to be adjusted within 45 to 65% since the cake becomes hard with a 40% or less water content.
Further, since a chlorinated rubber slurry is collected from a highly acidic aqueous medium, it limits the material of the centrifugal separator.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a method of producing a high quality chlorinated rubber from an acidic or highly acidic chlorinated rubber cake obtained by chlorinating a rubber latex or a water dispersion thereof efficiently with easy handling, and an apparatus therefor.
The present inventors studied elaborately to solve

the above-mentioned problems.
That is, the present invention provides a method for producing a chlorinated rubber comprising fluidized drying an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion with a drying medium to obtain preliminary dried powders, and fluidized drying again the preliminary dried powders.
Further, the present invention provides an apparatus for producing a chlorinated rubber equipped with an (A) unit comprising a fluidized drying means using a medium (hereinafter referred to as "medium fluidized drying means") with a supply opening for a chlorinated rubber cake, and containing a drying medium in its inside,
a bag filter connected with the medium fluidized drying means via a conduit, and
a fluidized drying means provided downstream of the bag filter.
Furthermore, the present invention provides an apparatus for producing the chlorinated rubber, comprising a (B) unit upstream of the (A) unit, the (B) unit being an apparatus for producing a chlorinated rubber cake from a chlorinated rubber slurry obtained after chlorinating a rubber latex or an aqueous dispersion, comprising:
a belt filter movable in the horizontal direction, and
a means for absorbing water contained in the chlorinated rubber slurry via the belt filter.
Still further, the present invention provides an apparatus for producing the chlorinated rubber comprising the (B) unit upstream of the (A) unit, and further comprising a

(C) unit upstream of the (B) unit, the (C) unit being an apparatus for producing a chlorinated rubber slurry obtained by chlorinating a rubber latex or an aqueous dispersion, comprising:
a reaction vessel for accommodating the reaction liquid, provided with an outlet portion for the reaction liquid,
a circulating line for guiding the reaction liquid from the outlet portion to the outside of the reaction vessel, and returning to the reaction vessel,
a heat exchanger provided at least one point in the circulating line, and
a UV lamp provided in the reaction vessel and/or the circulating line.
ACCOMPANYING BRIEF DESCRIPTION OF THE/DRAWINGS
Fig. 1 is a diagram for explaining one embodiment of the apparatus of the present invention.
Fig. 2 is a diagram for explaining an apparatus, which can be preferably connected with the apparatus of the present invention.
Fig. 3 is a diagram for explaining an apparatus, which can be preferably connected with the apparatus of the present invention.
Fig. 4 is a diagram for explaining a UV lamp, which can be preferably used in the apparatus of Fig. 3.
Figs. 5 to 7 are diagrams for explaining apparatus, which can be preferably connected with the apparatus of the present invention.
Fig. 8 is a diagram for explaining one embodiment of

the apparatus of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter the present invention will be explained in detail with reference to the accompanied drawings.
Fig. 1 is a diagram for explaining one embodiment of the apparatus of the present invention.
The apparatus 1 of the present invention comprises a medium fluidized drying means 2, a bag filter 3, and a fluidized drying means 4.
The medium fluidized drying means 2 is provided with a hot air supply opening 10 at the bottom portion for supplying hot air for drying. A flat perforated plate 6 and drying medium 7 thereon are provided downstream of the hot air supply opening 10. The drying medium in this embodiment is shown as medium balls 7. A large number of the medium balls 7, which have a diameter of 2 to 5 mm, are placed on the flat perforated plate 6 to the thickness of about 50 to 300 mm. As a material for the medium balls, a large one is not preferable since it may come in contact with chlorine or hydrochloric acid, and it is expected to flow. Further, one having a specific gravity similar to that of a chlorinated rubber cake is not also preferable. In view of these elements, the diameter of the medium balls 7 is preferably 2 to 5 mm as mentioned above, and a material is preferably alumina, silicon nitride, quartz, and the like. The flat perforated plate 6 allows the passage of hot air, but does not allow the passage of the medium balls.
A supply opening 5 for a chlorinated rubber cake is provided in the medium fluidized drying means 2 so that the

chlorinated rubber cake obtained by chlorinating an acidic highly acidic rubber latex is introduced therefrom. The introduced chlorinated rubber cake is dried according to the fluid motion of the medium balls 7 by the hot air to become powdery, and blown up to the upper part of the medium fluidized drying means 2, The temperature of the hot air is, for example, 50 to 130°C , preferably 70 to 100°C . According to the temperature range, the drying efficiency is improved, deterioration of the chlorinated rubber cake powders can be prevented, and further, adhesion and re-agglomeration of the powders can be restrained. By the medium fluidized drying means 2, most of the water contained in the chlorinated rubber cake can be eliminated so as to provide a wet powder.
The wet powder (powders of a chlorinated rubber) blown up to the upper part of the medium fluidized drying means 2 reaches a conduit 8. The conduit 8 is made from a material with a diameter and a length not preventing the passage of the powders of the chlorinated rubber. For example, it can be made from stainless steel, a fluororesin-coated material, and the like, with a 300 to 1,000 mm diameter and a 3 to 15 mm length.
The conduit 8 is connected with the bag filter 3 at the end. The bag filter 3 can be a known type comprising a plurality of cylindrical filter cloths. The powders of the chlorinated rubber passed through the conduit 8 contact with the bag filter 3, and are dropped to the fluidized drying means 4 at the lower part. Powders adhered to the bag filter 3 are blown away by compressed high pressure air supplied from a pulse air generator 9 provided above the bag filter 3 at appropriate intervals so as to reach the flow drying means 4.

The fluidized drying means 4 is provided below the , bag filter 3 for finishing the powders of the chlorinated rubber. A hot air supply opening 11 is provided at the bottom of the fluidized drying means 4 for supplying hot air for drying. A flat perforated plate 12 is provided downstream of the hot air supply opening 11. It is preferable that the flat perforated plate 12 does not allow the powders easily. The powders flow by the hot air blown from the hole portion of the flat perforated plate 12, are dried for finishing, and pass through a rotor valve 13 so as to be discharged from the powder output opening 14. A preferable temperature of the hot air in the flow drying means 4 is, for example, 60 to 100°C .
A preferable production embodiment of the chlorinated rubber cake to be used is as described below.
Fig. 2 is a diagram for explaining an apparatus, which can be preferably connected with the apparatus 1 of the present invention.
An apparatus 21 has a belt filter 22 of a ring shape formed with four rolls 30, 31, 32 and 33. The material of the belt filter 22 is not particularly limited as long as it does not allow the passage of fine particles of a chlorinated rubber but allow the passage of water. Examples thereof include a filter cloth. The belt filter 22 can be moved in the horizontal direction by the filter cloth driving roll 30.
An aqueous chlorinated rubber slurry is supplied on the belt filter 22. The supply amount of the chlorinated rubber slurry can be determined according to the size of the apparatus, the chlorination conditions, and the like. For example, it is preferable that it is supplied on the belt filter 22 by 5 to 25 ram thickness, most preferably by 20 mm or

less thickness. The belt filter 22 is moved in the horizontal direction by the filter cloth moving roll 30 to reach the position where means for absorbing the water contained in the chlorinated rubber slurry (flat perforated plates 23) are provided therebelow. The belt filter 22 stops at the position for water absorption of the chlorinated rubber slurry.
According to the embodiment of Fig. 2, a chlorinated rubber cake of the present invention can be obtained by absorbing the water in the chlorinated rubber slurry from the dishes 23 provided at two positions, which are interlocked to a vacuum system via a tank 27 through the belt filter 22 by reducing the pressure. The pressure reduction can be easily started or stopped by a valve 25. The absorbed water can be accommodated by the tank 27 so that it can be reused as needed. Accordingly, the water content of the chlorinated rubber cake can be adjusted at, for example, 45 to 60%. The pressure reduction time is preferably 15 to 150 seconds in view of the quality.
It is preferable that the chlorinated rubber cake after water absorption is moved with the belt filter 22 in a predetermined distance in the horizontal direction so as to be washed with water thereat. It is preferable that the temperature of the washing water is 50°C or higher in view of the filtration speed. As mentioned above, the belt filter 22 is stopped at a position where the washing water is supplied so that the washing water is supplied from a position above the belt filter 22, and the water is absorbed. According to the embodiment of Fig. 2, dishes 24, which are connected to a vacuum system via a tank 28, are provided at two positions. The pressure reduction can be easily started or stopped by a

valve 26. The absorbed water can be accommodated by the tank 28 so that it can be reused as needed. After the water ^ absorption process, the valves 25, 26 are shut out so that the dishes 23, 24 return to an ordinary pressure, with the belt filter 22 moved for absorbing the water in a supplied chlorinated rubber slurry as mentioned above. Accordingly, it is preferable that the filter cloth driving roll 30, the valve 25 and the valve 26 are interlocked. The adjusted chlorinated rubber cake moved with the belt filter 22 is dropped from the roll 33 to a cake receptacle 34.
The chlorinated rubber cake obtained accordingly can be supplied to the apparatus shown in Fig. 1 for drying.
The above-mentioned production method of a chlorinated rubber slurry is not particularly limited. For example, an apparatus disclosed in Japanese Patent Laid-Open No. 5-202101 can be used. However, since a large amount of heat is generated by reaction or dilution, the reaction liquid has a thixotropy property so that a remarkably long reaction time is needed in dealing with a large amount, and the chlorine utilization efficiency is poor and foam generation by the surfactant in the reaction liquid prevents the liquid transfer or washing according to the apparatus, sometimes it is not appropriate for a mass production. Accordingly, it is preferable to produce a chlorinated rubber slurry by the below-mentioned apparatus.
That is, the preferable apparatus is an apparatus for producing a chlorinated rubber slurry from a reaction liquid obtained by chlorinating a rubber latex or an aqueous dispersion, comprising:
a reaction vessel for accommodating the reaction

liquid, provided with an outlet portion for the reaction liquid,
a circulating line for guiding the reaction liquid from the outlet portion to the outside of the reaction vessel, and returning to the reaction vessel,
a heat exchanger provided at least one point in the circulating line, and
a UV lamp provided in the reaction vessel and/or the circulating line.
In Japanese Patent Laid-Open No. 5-202101, since the chlorination immediately occurs so that the heat generation in the reaction substantially finishes in several hours from starting the chlorination, a great amount of heat needs to be eliminated in a short time. According to the present invention, the reaction heat can be eliminated efficiently in a large amount, since a circulating line is provided outside the reaction vessel so as to circulate the reaction liquid and further, a heat exchanger is provided in the circulating line.
The reaction vessel needs to accommodate a highly acidic aqueous dispersion of a polyisoprene rubber and a chlorine gas (hereinafter referred to as a reaction liquid) without corrosion. As a material thereof, a glass lining can be presented. Further, it is preferable that the reaction vessel can have a 500 to 30,000 liter capacity, with a stirring means provided inside.
The reaction vessel is provided with an outlet portion, with the circulating line connected thereto. The position of the outlet portion of the reaction vessel can be optionally selected, but it is preferable to locate it, for example, at the bottom part of the reaction vessel so as not

to prevent the homogeneous mixing of the reaction liquid in the reaction vessel.
The length of the circulating line needs to be determined according to the size of the reaction vessel, the chlorination degree, and the line, however, it is, in general, 5 to 30 m. The shape of the circulating line is not particularly limited as long as the heat elimination effect is not disturbed and it is appropriate for locating a heat exchanger. In the case where the circulating line is pipe¬like, the diameter thereof is, for example, about 4 to 40 cm. The material of the circulating line needs to be not corrosive with respect to the reaction liquid, it is, for example, a glass lining.
The reaction liquid in the reaction vessel flows into the circulating line from the outlet portion of the reaction vessel by the function of a pump, and the like so as to flow in the circulating line. By the flow of the reaction liquid in the circulating line, the reaction heat is discharged to the outside. The flow rate of the reaction liquid can be optionally selected according to the length and the shape of the circulating line, the chlorination degree, and the like, but it is, for example, 0.1 to 10 m3/min. The circulating line starts from the outlet portion of the reaction vessel and returns to the reaction vessel. The finishing point of the circulating line is preferably at a position far from the outlet of the reaction vessel, and soaked in the liquid.
Although the reaction liquid has a thixotropy property, since it flows in the circulating line, the flowability of the reaction liquid is improved so that the

extension of the reaction time can be restrained.
The heat exchanger is provided at least at one point in the circulating line for further improving the heat eliminating effect. A heat exchanger of a known type can be used. Examples thereof include a tube type heat exchanger and a plate type heat exchanger, which are commercially available.
Furthermore, it is preferable to provide one or a plurality of a static mixer in the circulating line. The configuration enhances the chlorine gas dispersion so that the chlorine utilization efficiency is improved, the chlorination rate is increased, and the foam formation by the surfactant in the reaction liquid can be restrained. It is well known that a static mixer is an in-line stirrer without a driving portion where right-handed and left-handed spiral elements are provided alternately with the end of an element provided perpendicular to the end of adjacent elements, capable of efficiently mixing liquid, gas and flowable solid. Further, since the energy necessary for mixing corresponds with the pressure loss at the time the fluid passes through the mixer, the amount of the energy consumption is small. The number of the elements is optional, but it can be, for example, 4 to 24 pieces.
A chlorinated rubber is produced with the ultraviolet ray irradiation to the reaction liquid. The ultraviolet ray irradiation can be conducted by, for example, providing a UV lamp in the reaction vessel and/or the circulating line for improving the efficiency. It is confirmed that the chlorination can proceed smoothly with a UV lamp provided at either position, but it is preferable to provide it in the reaction vessel. Although the reaction rate

is facilitated by enforcing the ultraviolet ray irradiation intensity, the reaction heat rises accordingly. Therefore, the ultraviolet ray irradiation intensity can be optionally selected in consideration of these factors. Further, in the case where a UV lamp is provided in the circulating line, it is preferable to determine the size and the position of the UV lamp in consideration of the flow rate of the reaction liquid, the number of circulation, and the ability of the circulation pump.
As shown in Fig. 4, it is preferable that the UV lamp has a double structure for cooling the heat generated at the mercury lamp by cooling water where starting and stopping is controlled automatically for ensuring security.
At the time of operation, it is preferable, for example, to place an acid aqueous solution of a high concentration in the reaction vessel, introduce a saturated amount of a chlorine gas into the circulating line where the solution is circulated by a pump for sufficient mixing and dissolving, and then slowly inject an aqueous dispersion of a polyisoprene rubber thereto, while blowing a chlorine gas, considering the chlorine gas supply amount sufficient for reaction with the UV lamp on.
It is preferable that the chlorine gas and the aqueous dispersion are introduced from the upstream side of the static mixer.
The polyisoprene rubber to be used is a polymer containing an isoprene unit in a molecular chain as the main component. Concrete examples thereof include a natural rubber, a synthetic polyisoprene, or copolymers of isoprene and a monomer having a hydrophilic group, such as a hydroxyl

group, a carboxyl group, and an amide group, copolymers of isoprene and a vinyl monomer such as (meth)acrylate, copolymers of isoprene and another diene type monomer such as butadiene, grafted polyisoprene obtained by grafting maleic acid, maleic anhydride, or succinic acid. These can be used alone or in combination of two or more.
The average particle size of a polyisoprene rubber in an aqueous dispersion is, in general, 100 ^ m or less, preferably 20 // m or less, more preferably 1 ^ m or less. An excessively large average particle size prevent homogeneous chlorination so that it generates unevenness in the solubility with respect to an organic solvent such as toluene, to generate partially-undissolved part.
Examples of acids used for a high concentration aqueous solution of an acid include strong acids such as hydrochloric acid, sulfuric acid, and nitric acid. Among these examples, hydrochloric acid or a combination of hydrochloric acid and sulfuric acid or nitric acid is preferable in terms of smoothly conducting the chlorination process.
The concentration of the acid in the high concentration aqueous solution of an acid is, in general, 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more.
In the case where a natural rubber latex is used, a high chlorination can be achieved without rubber particle agglomeration with an acid concentration of 2% by weight or more, preferably 5% by weight or more under the presence of a surfactant described below. The upper limit of the acid concentration is in general, 40% by weight, preferably about

36% by weight
In the case where an aqueous dispersion of a polyisoprene rubber and a high concentration aqueous solution of an acid are mixed, the concentration of the polyisoprene rubber at the time of starting the chlorination reaction is, in general, 1% by weight or more, preferably about 2 to 10% by weight. A lower polymer concentration in the highly acidic aqueous dispersion is preferable in order to control the chlorination reaction, but in view of the balance with productivity, 2 to 10% by weight is appropriate. Furthermore, with the polymer concentration range, a highly acidic condition can be stably maintained.
In the case where an aqueous dispersion of a polyisoprene rubber and a high concentration aqueous solution of an acid are mixed, it is preferable that a surfactant exists in order to improve the dispersion of the rubber fine particles. However, in the case where the aqueous dispersion of the polyisoprene rubber contains the surfactant, addition of the surfactant is not needed.
As a surfactant, a nonionic surfactant, an anionic surfactant, a mixture thereof, and a nonionic-anionic surfactant, which do not degenerate by an acid can be preferably used. To a natural rubber latex, a nonionic or nonionic-anionic surfactant is extremely preferable for preventing agglomeration.
Examples of nonionic surfactants include a condensed product of polyoxyethylene polyoxypropylene, polyoxyalkylene alkylether, polyoxyalkylene nonylphenolether, sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, and polyoxyalkylene glycerin fatty acid ester. Among these

examples, those having an HLB (hydrophile-liphophile balance) of 8 or more are preferable.
Examples of anionic surfactants include higher alcohol sulfate, alkyl benzene sulfonic acid salt, alkyl phosphate salt, polyoxyalkylene sulfate, and dialkyl sulfosuccinic acid salt. However, higher fatty acid soap and the like, which can easily degenerate by acids, are not preferable.
Examples of nonionic-anionic surfactants include polyoxyethylene alkyl ether sodium sulfate, and polyoxyethylene alkyl aryl ether sodium sulfate.
The amount of the surfactant is preferably at the minimum level where the dispersion stability of a highly acidic aqueous dispersion of a polyisoprene rubber can be ensured. In general, it is 15 parts by weight or less with respect to 100 parts by weight of the polyisoprene rubber, preferably 0.1 to 10 parts by weight, more preferably 1 to 7 parts by weight. An excessively large ratio of the surfactant may affect on the chlorination.
The reaction temperature is preferably in the range of 0 to 90°C . With a temperature lower than 0°C , a problem of freezing of the medium may generate, on the other hand, with a temperature higher than 90°C , rubber particles can easily adhere to each other. It is preferable that the temperature is kept at a low temperature of about 40°C or less in the initial stage of the chlorination reaction and is raised in the later stage. The reaction time partly depends on the chlorination degree, but in general, it is about 2 to 20 hours. The chlorine gas can be supplied either by the feed type or the sealed type, and further, either in an ordinary

pressure or under load.
The chlorination degree can be determined optionally as needed. But in general, chlorination is conducted until the chlorine concentration (chlorine amount) in the chlorine rubber becomes in the range of 55 to 75% by weight. With an excessively low chlorine concentration, an obtained chlorinated rubber cannot dissolve in an organic solvent such as toluene easily to deteriorate the compatibility with a plasticizer or another resin. On the other hand, with an excessively large chlorine concentration, the chlorinated rubber cannot dissolve in an organic solvent easily.
A radical initializer or another additive can be added as needed at the time of chlorination. The viscosity of a chlorinated rubber in an organic solvent can be optionally selected by introducing a catalysis, air, an oxide, and the like at the time of chlorination and adjusting the introduction amount.
A preferable embodiment of the present invention is that a chlorinated rubber slurry obtained accordingly is processed to be a chlorinated rubber cake by the apparatus shown in Fig. 2, and is dried by the apparatus shown in Fig. 1. A further preferable embodiment is that, as shown in Fig. 8, the apparatus are interlocked and automatically operated.
EXAMPLES
Hereinafter the present invention will be further described with reference to examples and comparative examples. Production Example 1 of a Chlorinated Rubber Slurry
A chlorinated rubber slurry was produced with an apparatus shown in Fig. 3.

An apparatus 41 of Fig. 3 comprises a 500-liter cylindrical reaction vessel 42 provided with a stirrer 52, a thermometer 53, a UV lamp 54 (a high pressure mercury lamp having a configuration of Fig. 4, produced by Toshiba Lightec Corp.), having an outlet portion at the lower part; a pipe¬like circulating line 44 having 10 m length and 5 cm diameter, starting from the outlet portion 43 of the reaction vessel 42, for circulating the reaction liquid, and a heat exchanger 45 (tube type heat exchanger produced by Le Carbon Corp.) at one point of the circulating line. The circulating line 44 is provided with a chlorine gas injecting opening 46, a latex injecting opening 47, and an injecting pump (not illustrated) are provided. A circulating pump 48 is provided between the reaction vessel 42 and the chlorine gas injecting opening 46.
444 kg of 35% by weight of hydrochloric acid was placed in the reaction vessel. The circulating pump was operated while stirring the hydrochloric acid with a stirrer at 107 rpm so as to circulate the hydrochloric acid from the outlet portion into the circulating line at a rate of 10 m3/hour. The temperature of the circulating hydrochloric acid was maintained at 10°C or lower with a chlorine gas injected into the circulating line at a rate of 9.6 kg/hour and dissolved.
2.5 kg of polyoxyalkylene nonyl phenol ether (solid component concentration: 10% by weight) and 11.8 kg of pure water were added to 41.7 kg of a natural rubber latex preliminarily stabilized by a low ammonia treatment (solid component concentration: 60%), and mixed homogeneously to prepare an aqueous dispersion (solid component concentration: 45% by weight). 56.0 kg of the aqueous dispersion was

injected from the latex injecting opening of the circulating line over 4 hours with the UV lamp on and the temperature of the reaction vessel maintained at 30°C . Then 71.3 kg of a chlorine gas and 200 1 of oxygen were introduced from the chlorine gas injecting opening 46 over 14 hours with the temperature in the apparatus maintained at 20 to 30°C . The dispersion state of the particles was extremely good during the chlorination.
After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 65% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 20 cps/25°C . Production Example 2 of a Chlorinated Rubber Slurry
With the apparatus and the process same as production example 1, a chlorinated rubber slurry was produced. However, the UV lamp 54 was placed in the circulating line 44 as shown in Fig. 5.
As a result, the dispersion state of the particles was extremely good during the chlorination.
After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 65% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 21 cps/25°C . Production Example 3 of a Chlorinated Rubber Slurry
With the apparatus and the process same as production example 1, a chlorinated rubber slurry was

produced. However, static mixers 49 were provided at two points, that is, between the chlorine gas injecting opening 46 and the latex injecting opening 47, and between the latex injecting opening 47 and the heat exchanger 45 as shown in Fig. 6. Further, 80.1 kg of the chlorine gas and 200 1 of oxygen were introduced from the injecting opening 46 provided upstream of the static mixer over 14 hours.
As a result, the dispersion state of the particles was extremely good during the chlorination.
After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 17 cps/25°C . Production Example 4 of a Chlorinated Rubber Slurry
With the apparatus and the process the same as production example 3, a chlorinated rubber slurry was produced. However, the UV lamp 54 was placed in the circulating line 44 as shown in Fig. 7. Further, 81.0 kg of the chlorine gas and 200 1 of oxygen were introduced from the injecting opening 46 provided upstream of the static mixer over 14 hours.
As a result, the dispersion state of the particles was extremely good during the chlorination.
After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated

product was transparent and had a viscosity of 21 cps/25°C . Production Example 5 of a Chlorinated Rubber Slurry
The production example 3 was repeated except that 40 1 of oxygen was used.
As a result, the dispersion state of the particles was extremely good during the chlorination.
After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 150 cps/25°C . Production Example 6 of a Chlorinated Rubber Slurry
The production example 4 was repeated except that 38 1 of oxygen was used.
As a result, the dispersion state of the particles was extremely good during the chlorination.
After the reaction, chlorinated polyisoprene fine particles were separated by filtration, washed with water, and dried at 50°C under a reduced pressure. The chlorine content of the dried white powdery chlorinated product was 67% by weight. A 20% by weight toluene solution of the chlorinated product was transparent and had a viscosity of 160 cps/25°C . Production Example of a Chlorinated Rubber Cake
Chlorinated rubber cakes were produced from the chlorinated rubber slurries prepared, in production examples 1 to 6 with the apparatus shown in Fig. 2.
The slurry containing 12% of a chlorinated rubber after the chlorination reaction (before drying) was supplied at a rate of 500 kg/hour onto a horizontally-movable filter

cloth in production examples 1 to 6. The moving rate of the filter cloth was set at 3 seconds in 40 seconds. Therefore, the pressure reduction time was 37 seconds where the thickness of the chlorinated rubber slurry was controlled to be 8 to 11 mm. Then the filter cloth was moved horizontally by 200 cm where washing water of 70°C was supplied onto the chlorinated rubber slurry at a rate of 750 kg/hour for water absorption. After about 40 minutes, discharge of a chlorinated rubber cake was started onto a cake receptacle. The water content of the obtained chlorinated rubber cake was 55%, which allows easy mechanical flow. Example 1
The present invention was implemented with the apparatus of Fig. 1. The apparatus (Fig. 3, 5 to 7) used in production examples 1 to 4 of a chlorinated rubber slurry, the apparatus (Fig. 2) used in production example of a chlorinated rubber cake, and the apparatus of Fig. 1 were interlocked with an ordinary method.
Hot air of 80°C was provided from the hot air blowing opening 10 such that the medium balls 7 can sufficiently move. The chlorinated rubber cake having a 55% water content obtained in production example of the chlorinated rubber cake (the cake was obtained from the production example 1 slurry) was introduced from the chlorinated rubber cake supply opening 5 at a rate of 60 kg/hour into the medium fluidized drying means 2 to obtain a wet powder (powders of a chlorinated rubber). The powders after passing through the conduit 8 came in contact with the bag filter 3, and reached the fluidized drying means 4 at the downstream side. The powders adhered to the bag filter 3 were

blown away by the pulse air from the pulse air generator 9, which is operated for 0.5 second with an interval of 30 seconds. Hot air of 80°C from the hot air blowing opening 11 at the bottom part of the fluidized drying means 4 passed through the flat perforated plate 12 to further dry the powders. The powders were finally obtained from the powder output opening 14 through the rotary valve 13 at a rate of about 26 kg/hour. The water content of the obtained powders was 0.2% or less. The time required from the input of the chlorinated rubber cake to the powder output opening 14 was about 1 hour. The viscosity of a 20% toluene solution of the final powders obtained in this example was 18 cp, which was always constant. Next, the Example 1 was repeated except that the chlorinated rubber slurry was changed to those obtained by the production examples 2 to 6. The same results were obtained. Further, The viscosity of a 20% toluene solution of the final powders obtained from the production examples 2 to 6 slurries were 19, 15, 19, 135 and 144 cp, respectively, which was always constant. Comparative Example 1
A block of 20 kg of the chlorinated rubber cake having a 55% water content same as example 1 (the cake was obtained from the production example 1 slurry) formed by hands was placed in a shelf type drier to introduce hot air from the lower part where three plates of 30 mm height, 600 mm length and 1,000 mm width can be set. Then hot air of 120 to 130°C was introduced for 2 hours. The water content of the cake was 15% then. After pulverization, it was placed again in the drier to be dried for 4 hours while introducing hot air of 100°C from the lower part to obtain a chlorinated rubber of a

0.3% water content. The viscosity of a 20% toluene solution thereof was irregular in the range of 12 to 17 cp depending on the sampling parts.
Next, the Comparative Example 1 was repeated except that the chlorinated rubber slurry was changed to those obtained by the production examples 2 to 4. The same results were obtained. Further, the Comparative Example 1 was repeated except that the chlorinated rubber slurry was changed to those obtained by the production examples 5 and 6. The viscosity of a 20% toluene solution thereof was irregular in the range of 90 to 120 cp depending on the sampling parts.
According to the present invention, since a chlorinated rubber cake is fluidized-dried with a drying medium, most of the water content in the cake can be eliminated without adhesion to the wall portion of the drier. Further, since it is applied with finishing-drying by fluidized-drying again, the viscosity change of the chlorinated rubber can be restrained. Besides, since the powders finally obtained have an appropriate particle size, it is easy to handle. Furthermore, since the method of the present invention allows to have a drying process at a temperature lower than conventional ones, the material of the drier can be selected in a wider range. That is, according to the present invention, a method of obtaining a high quality chlorinated rubber efficiently with easy handling from an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion, and an apparatus therefor can be provided.
A chlorinated rubber can be obtained further efficiently in combination with the production apparatus of a

chlorinated rubber slurry and/or the production apparatus of a chlorinated rubber cake as described above.

1. A method for producing a chlorinated rubber
comprising:
fluidized drying an acidic or highly acidic chlorinated rubber cake obtained after chlorinating a rubber latex or an aqueous dispersion with a drying medium to obtain a preliminary dried powders; and
fluidized drying again the preliminary dried powders .
2. The method according to claim 1, wherein the
temperature of the fluidized drying with the drying medium is
50 to 130°C .
3. The method according to claim 2, wherein the
drying medium is medium balls having a 2 to 5 mm diameter.
4. The method according to claim 1, wherein the
chlorinated rubber cake is obtained by supplying an acidic or
highly acidic chlorinated rubber slurry after chlorinating the
rubber latex or the aqueous dispersion onto a horizontally-
movable belt filter, and absorbing water contained in the
chlorinated rubber slurry.
5. The method according to claim 1, wherein the
chlorinated rubber slurry is obtained by taking the acidic or
highly acidic latex or aqueous dispersion of the rubber in a
reaction vessel outside the reaction vessel by a circulating
line so that a chlorine gas is blown to the latex or the

dispersion for chlorination while eliminating the generated heat of the latex or the aqueous dispersion by a heat exchanger.
6. An apparatus for producing a chlorinated rubber equipped with a first unit
comprising:
a fluidized drying means using a medium with a supply opening for a
chlorinated rubber cake, and drying medium in the inside;
a bag filter connected with the fluidized medium drying means via a conduit;
and
a fluidized drying means provided downstream of the bag filter.
7. The apparatus according to claim 6, comprising a second unit upstream of the
first unit, said second unit being an apparatus for producing the chlorinated
rubber cake from a chlorinated rubber slurry obtained after chlorinating a
rubber latex or an aqueous dispersion, comprising:
a belt filter movable in the horizontal direction; and
a means for suctioning water contained in the chlorinated rubber slurry via the
belt filter.
8. The apparatus according to claim 7, wherein third unit upstream of said second
unit, said third unit being an apparatus for producing the chlorinated rubber
slurry obtained by chlorinating a rubber latex or an aqueous dispersion,
comprising:
a reaction vessel for accommodating the reaction liquid, provided with an outlet portion for the reaction liquid,

a circulating line for guiding the reaction liquid from the outlet portion to outside of the reaction vessel, and returning it back to the reaction vessel, a heat exchanger provided at at least one point in the circulating line, and a UV lamp provided in the reaction vessel and/or the circulating line.
9. A method for producing a chlorinated rubber substantially as herein described
with reference to the accompanying drawings.
10. An apparatus for producing a chlorinated rubber substantially as herein
described with reference to the accompanying drawings.

Documents:

2833-mas-1997 abstract duplicate.pdf

2833-mas-1997 abstract.pdf

2833-mas-1997 claims duplicate.pdf

2833-mas-1997 claims.pdf

2833-mas-1997 correspondence others.pdf

2833-mas-1997 correspondence po.pdf

2833-mas-1997 description (complete) duplicate.pdf

2833-mas-1997 description (complete).pdf

2833-mas-1997 drawings duplicate.pdf

2833-mas-1997 drawings.pdf

2833-mas-1997 form-19.pdf

2833-mas-1997 form-2.pdf

2833-mas-1997 form-26.pdf

2833-mas-1997 form-4.pdf

2833-mas-1997 form-6.pdf

2833-mas-1997 others-1.pdf

2833-mas-1997 others.pdf

2833-mas-1997 pct search report.pdf

2833-mas-1997 petition.pdf

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Patent Number

200457

Indian Patent Application Number

2833/MAS/1997

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

19-May-2006

Date of Filing

10-Dec-1997

Name of Patentee

ASAHI DENKA KOGYO K.K

Applicant Address

2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116

Inventors:

#	Inventor's Name	Inventor's Address
1	NAOYASU KURITA	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116
2	JUN-ICHI HISANO	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116
3	MASANORI KONISHI	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116
4	TADASHI JANADO	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116
5	MUTSUMI NAKAYAMA	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116
6	SHIJI NAKAND	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116
7	TOSHIYUKI YOSHIDA	C/O. ASAHI DENKA KOGYO K.K., 2-35, HIGASHIOGU 7-CHOME, ARAKAWA-KU, TOKYO 116

PCT International Classification Number

F26B1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	8-337169	1996-12-17	Japan
2	8-331098	1996-12-11	Japan
3	8-331115	1996-12-11	Japan