WO2003080681A1 - Hydrogenated conjugated diene based polymer latex and method for production thereof, and hydrogenated conjugated diene based polymer rubber - Google Patents

Abstract

A latex of a hydrogenated conjugated diene based polymer having a content of a platinum group element of 100 ppm based on the polymer; a hydrogenated conjugated diene based polymer rubber which is prepared through the separation from said latex; and a method for producing said latex which comprises dissolving or dispersing a hydrogenation catalyst containing a platinum group element compound in a latex of a conjugated diene based polymer, performing the hydrogenation of a carbon-carbon unsaturated bond, adding a complexing agent capable of forming a water-insoluble complex with the platinum group metal into the resulting hydrogenated polymer latex, to form a precipitate, and separating the precipitate.

Description

 Description Hydrogenated conjugated polymer latex and method for producing the same, and hydrogenated conjugated polymer rubber

 The present invention relates to a hydrogenated conjugated polymer latex, a method for producing the same, and a hydrogenated conjugated polymer rubber.

 The hydrogenated conjugated polymer latex of the present invention is characterized in that the amount of residual hydrogenation catalyst contained in the hydrogenated conjugated polymer constituting the latex is extremely low.

 Background art

 A useful means of modifying conjugated polymers is to selectively or partially hydrogenate carbon-carbon unsaturated bonds of the polymer, such as hydrogenated acrylonitrile butadiene copolymer. Is often adopted. Hydrogenated conjugated polymer rubbers are used in a wide range of industrial applications because of their excellent properties such as oil resistance, weather resistance, ozone resistance, heat resistance, and cold resistance.

As a typical process for producing such a hydrogenated conjugated polymer, (1) a step of emulsion-polymerizing a monomer containing a conjugated gen and coagulating and drying the obtained latex to prepare a raw material polymer (2) a step of dissolving the raw material polymer in an organic solvent and hydrogenating using a supported (heterogeneous) catalyst in which a hydrogenation catalyst is supported on a carrier insoluble in the organic solvent; (3) hydrogen There is known a process comprising a step of separating a supported catalyst from a reaction mixture and recovering a target hydrogenated polymer from an organic solvent. However, in the above process, the raw material polymer once recovered from the latex of the conjugated gen-based polymer was pulverized with a crusher or the like and dissolved again in an organic solvent.The organic solvent used in the hydrogenation reaction was distilled off after the reaction. It requires complicated operations such as squatting, and it is hard to say that it is too roundabout and efficient. Further, for example, it is conceivable to use a hydrogenated conjugated gen-based polymer in a latex state for an application such as an adhesive. However, the process J: cannot directly produce a hydrogenated polymer in such a state. Therefore, there is a strong demand for the development of a process for hydrogenating a conjugated gen-based polymer in a latex state, and various studies have been made (for example, see US Pat. No. 3,988,208; 2-1 7 8 3 0 5 publication).

 However, in a hydrogenation reaction in a latex state containing an aqueous medium, when a supported catalyst is used as in the above-described conventional process, the catalytic activity was not sufficiently satisfactory. In addition, when an unsupported catalyst that is dissolved or dispersed in an aqueous medium is used, it is extremely difficult to separate the catalyst after the completion of the reaction, and the cost of the catalyst increases significantly because the catalyst cannot be recovered and reused. There was. Furthermore, when a latex state hydrogenated conjugated gen-based polymer is used as a product, a large amount of residual catalyst is mixed, and quality problems such as coloring are likely to occur. Disclosure of the invention

 In view of the above circumstances, it is an object of the present invention to provide a hydrogenated conjugated polymer latex in which the amount of metal derived from the hydrogenation catalyst used in the production process is extremely small, inexpensive, and free from quality problems such as coloring. And a hydrogenated conjugated gen-based polymer rubber.

 Still another object is to provide a simplified method for producing a hydrogenated conjugated polymer latex in which the carbon-carbon unsaturated bond of the conjugated polymer is hydrogenated in the form of a latex. An object of the present invention is to provide a method for producing a hydrogenated conjugated polymer latex which is easy to separate and is industrially advantageous.

 The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, dissolve or disperse a hydrogenation catalyst containing a platinum group element compound in a conjugated gen-based polymer latex. The carbon-carbon unsaturated bond is hydrogenated, and the precipitate formed by adding a complexing agent that forms a water-insoluble complex with the platinum group element to the resulting hydrogenated polymer latex is then filtered, for example. It has been found that by separation by means, a hydrogenated conjugated polymer latex containing a small amount of metal derived from the hydrogenation catalyst can be produced extremely efficiently.

In addition, the improved method as described above has the following problems. (1) Since the unsupported catalyst dissolved or dispersed in the latex, the catalyst for the conjugated gen-based polymer in the latex can be used. (2) Since the used hydrogenation catalyst can be easily recovered and reused, there is a problem in economical efficiency even if a large amount of catalyst is used. (3) The present invention has been completed by confirming that it has the following advantages: (3) the amount of residual catalyst in the obtained latex is extremely small, so there is no adverse effect on the quality of latex products or rubber products; I came to.

 Thus, according to the present invention, first, a latex of a hydrogenated conjugated gen-based polymer having a content of a platinum group element per polymer of 100 ppm or less is provided. Secondly, there is provided a hydrogenated conjugated gen-based polymer rubber having a platinum group element content of 100 ppm or less, which is obtained by separating from the above latex.

 Further, thirdly, a hydrogenation catalyst containing a platinum group element compound is dissolved or dispersed in a latex of a conjugated gen-based polymer to hydrogenate carbon-carbon unsaturated bonds of the polymer, and then to form A method for producing a hydrogenated conjugated polymer-based latex, comprising separating a precipitate formed by adding a complexing agent that forms a water-insoluble complex with a platinum group element to a hydrogenated polymer latex. Is provided. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a cross-sectional view showing an example of a part of a filter of a filtration device for separating a precipitate formed by adding a complexing agent to a latex of a hydrogenated polymer. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the hydrogenated conjugated polymer latex of the present invention, the method for producing the same, and the hydrogenated conjugated polymer rubber will be described in detail.

 The latex of the hydrogenated conjugated diene polymer of the present invention is characterized in that the content of the platinum group element per polymer is 100 ppm or less. The content of the platinum group element per polymer is preferably 80 ppm or less, more preferably 50 ppm or less.

Further, the hydrogenated conjugated gen-based polymer rubber of the present invention is a rubber obtained by separation from the latex, wherein the content of the platinum group element per polymer rubber is 100 ppm. It is characterized by the following. The content of the platinum group element per polymer rubber is preferably at most 80 ppm, more preferably at most 50 ppm.

 The hydrogenated conjugated polymer rubber and latex of the present invention in which the content of the platinum group element derived from the hydrogenation catalyst is extremely low as described above does not have any quality problems such as coloring. The lower the content of the platinum group element, the better, and the lower limit is not limited. Generally, a hydrogenated conjugated polymer rubber having a content per polymer rubber of about 5 ppm or less is produced industrially advantageously. It is difficult to do.

 The weight average molecular weight (gel permeation 'chromatography method, standard polystyrene conversion) of the hydrogenated conjugated gen-based polymer constituting the latex is not particularly limited, but is usually 50,000 to 500,000. Range.

 The solid content concentration of the conjugated polymer latex as described above is not particularly limited, but is usually 2 to 70% by weight, preferably 5 to 60% by weight. The solid concentration can be appropriately adjusted by a known method such as a blending method, a dilution method, and a concentration method. The latex containing the hydrogenated conjugated polymer having a reduced platinum group element content as described above is useful as an adhesive, a coating agent, a paint, a raw material for dip-formed gloves, and the like. Since the amount of residual platinum group elements in latex is significantly reduced, when used as an adhesive, coating agent, paint, etc., the corrosion resistance of the adhered or coated metal material is high, and the residual platinum group elements cause Since there is no darkening, coating agents and paints have a high degree of freedom in coloring. Gloves obtained by dip-forming latex are suitable for work such as a semiconductor device manufacturing process.

 The latex of the hydrogenated conjugated polymer of the present invention is obtained by dissolving or dispersing a hydrogenation catalyst containing a platinum group element compound in a conjugated polymer polymer latex to form a carbon-carbon unsaturated bond of the polymer. Is hydrogenated, and then a precipitate formed by adding a complexing agent that forms a water-insoluble complex with a platinum group element to the latex of the hydrogenated polymer to be produced is produced.

The latex of a conjugated gen-based polymer to which the present method can be applied is a latex composed of a homopolymer or a copolymer of a conjugated gen monomer, and one or more conjugated gen monomers or a conjugated gen monomer It is produced by a conventionally known emulsion polymerization method by combining at least one kind of monomer copolymerizable with〗 and at least one kind of conjugated monomer. The conjugated diene monomer is not particularly limited as long as it is a polymerizable monomer having a conjugated diene structure. For example, Ί, 3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2, Examples include 3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, and 1,3-pentadiene. Of these, 1,3-butadiene and 2-methyl-1,3-butadiene are preferred, and 1,3-butadiene is particularly preferred.

 Monomers copolymerizable with the conjugated diene monomer include, for example, α, β—: L thylene unsaturated monotriles such as acrylonitrile, methacrylonitrile, crotonditrile, and vinylidene cyanide. Α, 8-ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid and itaconic acid; methyl acrylate, η-butyl acrylate, 2-ethylhexyl acrylate, Q !, such as trifluoroethyl acrylate, methyl methacrylate and methyl crotonate; ethylenically unsaturated carboxylic acid esters; α, 8-ethylenically unsaturated carboxylic acid amides such as acrylamide and methacrylamide; Styrene, vinyl acetate such as methylstyrene, p-methylstyrene, divinylbenzene, vinylpyridine Aromatic compounds; vinyl ether compounds such as full old Roe chill ethers; vinyl acetate, vinyl ester le such as propylene Sainsan vinyl and like et be.

 Among these monomers, monomers having an electron-withdrawing functional group are preferable from the viewpoint that the hydrogenation reaction in the present invention proceeds slowly, and α, monoethylenically unsaturated ditrimethyl monomers are preferred. In particular, acrylonitrile is preferably used.

 A preferred conjugated diene polymer is a copolymer of a conjugated diene monomer and an α, / 3-ethylenically unsaturated nitrile monomer, in particular, 1,3-butadiene 30 to 95% by weight More preferably, it is a copolymer of 45 to 85% by weight and acrylonitrile of 5 to 70% by weight, more preferably 15 to 55% by weight.

Emulsion polymerization is generally performed in an aqueous medium using a radical polymerization initiator. Known polymerization initiators may be used. The polymerization reaction may be a batch system, a semi-batch system, or a continuous system, and the polymerization temperature and pressure are not particularly limited. The emulsifier to be used is also not particularly limited, and may be an anionic surfactant, a surfactant, an amphoteric surfactant, Nonionic surfactants and the like can be used, but anionic surfactants are preferred. These emulsifiers may be used alone or in combination of two or more. The amount used is not particularly limited.

 Although the monomer composition ratio in the conjugated gen-based polymer is not particularly limited, it is usually 5 to 100% by weight of the conjugated gen monomer and 95 to 0% by weight of a monomer copolymerizable therewith. It is preferably 10 to 90% by weight of a conjugated diene monomer and 90 to 10% by weight of a monomer copolymerizable therewith.

 The hydrogenation catalyst used in the production method of the present invention is a water-soluble or water-dispersible compound of a platinum group element (ruthenium, rhodium, palladium, osmium, iridium, platinum). Such a hydrogenation catalyst is dissolved or dispersed in the above-mentioned latex without being supported on a carrier and subjected to a hydrogenation reaction. As the hydrogenation catalyst, palladium or rhodium compound is preferable, and radium compound is particularly preferable. Further, two or more platinum group element compounds may be used in combination, but also in this case, it is preferable to use a palladium compound as a main catalyst component.

 The palladium compound is not particularly limited as long as it is water-soluble or water-dispersible, preferably water-soluble, and has hydrogenation catalytic activity. Usually, a palladium compound having a valence of II or IV is used, and its form is a salt / complex.

 Examples of the palladium compound include organic acid salts such as palladium acetate and palladium cyanide; halides such as palladium fluoride, palladium chloride, palladium bromide, and palladium iodide; oxyacid salts such as palladium nitrate and palladium sulfate; Palladium oxide; Palladium hydroxide; Palladium compounds such as dichloro (cyclopentadiene) palladium, dichloro (norbornadiene) palladium, dichlorobis (triphenylphosphine) palladium, sodium palladium tetradecarate, ammonium hexahexaparadiadate; tetra Complex salts such as potassium cyanopalladate; and the like.

Among these palladium compounds, palladium acetate, palladium nitrate, palladium sulfate, palladium chloride, sodium tetrachloropalladium, and ammonium hexachloropalladate are preferred, and palladium acetate, palladium nitrate and palladium chloride are more preferred. Rhodium compounds include halides such as rhodium chloride, rhodium bromide and rhodium iodide; inorganic acid salts such as rhodium nitrate and rhodium sulfate; rhodium acetate, rhodium formate, rhodium propionate, rhodium butyrate, rhodium valerate, Organic acid salts such as rhodium naphthenate and rhodium acetylacetonate; rhodium oxide; rhodium trihydroxide; and the like.

 Such a compound of the platinum group element can be obtained from a commercially available product, or can be used after being prepared by a known method. The method of dissolving or dispersing the compound of the platinum group element in the latex is not particularly limited, and examples thereof include a method of directly adding the compound to the latex and a method of dissolving or dispersing the compound in water. . In the latter method, for example, inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, bromic acid, perchloric acid, and phosphoric acid; sodium salts of these inorganic acids, potassium salts; organic acids such as acetic acid; The solubility in water is improved, which may be preferable.

 In the method for producing a conjugated polymer latex of the present invention, the hydrogenation catalyst is dissolved or dispersed in the conjugated polymer latex, and the hydrogenation reaction in the latex state is efficiently performed. Let it proceed. When the hydrogenation reaction is performed under basic conditions, the reaction efficiency is further improved and the amount of catalyst used can be reduced. Such basic conditions are not particularly limited as long as the pH of the hydrogenation reaction solution (latex) measured by a pH meter is more than 7, and is preferably 7.2 to 13 and more preferably. Is in the range of 7.5 to 12.5, more preferably 8.0 to 12. The basic compound for making the hydrogenation reaction solution basic is not particularly limited, and examples thereof include an alkali metal compound, an alkaline earth metal compound, ammonia, ammonium chloride, and an organic amine compound. Preferably, they are an alkali metal compound and an alkaline earth metal compound.

Examples of the alkali metal compound include hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; carbonate compounds such as lithium carbonate, sodium carbonate, and potassium carbonate; lithium hydrogen carbonate, sodium hydrogen carbonate, and hydrogen carbonate power. Bicarbonate compounds such as lithium; oxides such as lithium oxide, potassium oxide and sodium oxide; organic acid salt compounds such as potassium acetate and sodium acetate; lithium methoxide, lithium ethoxide, sodium methoxide; Sodium ethoxide, Alkoxides such as potassium tert-butoxide; phenoxides such as sodium phenoxide and potassium phenoxide; and the like. Preferred are alkali metal hydroxides, carbonate compounds and bicarbonate compounds, and more preferred are hydroxides.

 Examples of the alkaline earth metal compound include hydroxides, carbonate compounds, hydrogen carbonate compounds, oxides, organic acid salt compounds, alkoxides of alkaline earth metals such as magnesium, calcium, strontium, and barium. Phenoxides and the like. Preferred are hydroxides, carbonate compounds, and hydrogen carbonate compounds of alkaline earth metals, and more preferred are hydroxides.

 Examples of the ammonium salt compound include ammonium carbonate and ammonium hydrogen carbonate. Examples of the organic amine compound include aliphatic, alicyclic, and aromatic mono- and polyamino compounds, such as triethylamine, ethanolamine, morpholine, N-methylmorpholine, pyridine, hexamethylenediamine, and dodecamethylenediamine. And xylylenediamine.

 These basic compounds can be used as they are, or can be used by diluting or dissolving with an organic solvent such as water or alcohol. The basic compounds may be used alone or in combination of two or more, and the amount used may be appropriately selected so that the hydrogenation reaction solution exhibits basicity. The method and timing of adding the basic compound to the hydrogenation reaction solution are not particularly limited.For example, before adding the hydrogenation catalyst to the hydrogenation reaction solution, the basic compound is added to the latex in advance. And a method of adding a basic compound after the start of the hydrogenation reaction.

 Further, in order to maintain the stability of the platinum group element compound in the latex, as a hydrogenation catalyst stabilizer, the latex is preferably soluble or dispersible in the latex and has a weight average molecular weight of preferably from 1,000 to 100. A polymer compound having a molecular weight of 0.000 can be used. By the addition of the stabilizer, the catalytic activity of the hydrogenation catalyst can be increased, the catalyst usage can be reduced, and the storage stability of the catalyst solution can be improved.

Hydrogenation catalyst stabilizers are soluble or dispersible in latex (meaning that they are in a stable dispersed state such as colloidal form), and are aggregated in latex. Any material can be used as long as it can maintain the hydrogenation catalyst in a dissolved or dispersed state without causing leaching. Specific examples of the hydrogenation catalyst stabilizer include polymers of a vinyl compound having a polar group in a side chain such as polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, and polyalkyl vinyl ether; sodium polyacrylate, and polyacrylic acid. Metal salts of polyacrylic acid such as realm; polyethers such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer; cellulose derivatives such as carboxymethylcellulose and hydroxypropylcellulose; gelatin, albumin And natural polymers; and the like. Among them, a polymer or polyether of a vinyl compound having a polar group in a side chain is preferable. Among polymers of a vinyl compound having a polar group in the side chain, polyvinyl pyrrolidone and polyalkyl vinyl ether are particularly preferred.

 Further, the molecular weight of these polymer compounds is represented by the following formula: weight average molecular weight (M w), Ί, 0000 to 100, 000, preferably 2, 000 to 500, 000. It is. When the Mw of the high molecular compound is within this range, the storage stability of the catalyst solution is further improved, and the catalytic activity in the hydrogenation reaction is improved.

 The hydrogenation catalyst stabilizer can be dissolved or dispersed in latex together with the hydrogenation catalyst and used for the hydrogenation reaction. In this case, the concentration of the hydrogenation catalyst stabilizer in the latex is preferably 0.5 to 20 times, more preferably 1 to 10 times, the weight of the metal element in the hydrogenation catalyst. .

 [0 0 1 9]

 The hydrogenation catalyst stabilizer of the present invention can be dissolved or dispersed in water or an organic solvent together with the hydrogenation catalyst, prepared in advance as a hydrogenation catalyst solution, and supplied to the hydrogenation reaction. When the catalyst solution is an aqueous solution, for example, an inorganic acid such as nitric acid, sulfuric acid, hydrochloric acid, bromic acid, perchloric acid, or phosphoric acid; a metal salt such as a sodium salt or a potassium salt of such an inorganic acid; an organic acid such as acetic acid An acid; etc., which may increase the solubility of the hydrogenation catalyst in water. In this case, the concentration of the acid in the aqueous catalyst solution is preferably 1 to 20 times, more preferably 1 to 10 times the molar amount of the metal element in the hydrogenation catalyst.

In particular, the method for preparing the catalyst aqueous solution includes a step of preparing an acidic aqueous solution of the hydrogenation catalyst. Next, it is preferable to include a step of adding the hydrogenation catalyst stabilizer of the present invention to the aqueous solution.

 The catalyst aqueous solution does not cause aggregation or precipitation of the hydrogenation catalyst even after standing at 25 ° C for 1 hour or more, preferably 1 day or more, more preferably 14 days or more. The temperature of the hydrogenation reaction is usually 0 to 200, preferably 5 ° C to 150 ° C, more preferably 10 ° to 100 ° C. An excessively high reaction temperature is not desirable because side reactions such as hydrogenation of a nitrile group may occur. On the other hand, if the reaction temperature is too low, the reaction rate is reduced, which is not practical.

 The pressure of the hydrogen is usually from atmospheric pressure to 20 MPa, preferably from atmospheric pressure to 15 MPa, more preferably from atmospheric pressure to 10 MPa. The reaction time is not particularly limited, but is usually 30 minutes to 50 hours.

 According to the method for producing a conjugated gen-based polymer latex of the present invention, in particular, the hydrogenation reaction under basic conditions, the hydrogenation reaction proceeds rapidly despite the reaction in the latex state. The hydrogenation rate (the ratio of hydrogenated carbon-carbon double bonds to the total number of carbon-carbon double bonds present in the polymer before the reaction) of the obtained hydrogenated conjugated polymer is determined by the above-mentioned various types. By appropriately changing the reaction conditions, it can be arbitrarily controlled in the range of 1 to 100%. The hydrogenation rate, expressed as iodine value, is preferably less than 120.

 The greatest feature of the method for producing a conjugated gen-based polymer latex according to the present invention is that a platinum group element present in an aqueous medium and a polymer particle of the latex after completion of the hydrogenation reaction is replaced with a platinum group element. It is a post-treatment and recovery of a catalyst that uses a complex forming ability to precipitate in a latex in a separable shape larger than polymer particles or to separate by precipitation and aggregation. That is, it is essential to separate a precipitate formed in the latex by hydrogenating the conjugated gen-based polymer in a latex state and then adding a complexing agent that forms a water-insoluble complex with the platinum group element. Features. By such a complexing agent treatment, the hydrogenation catalyst can be efficiently separated.

Prior to or simultaneously with the addition of the complexing agent, an oxidizing agent is added to the reaction mixture containing the hydrogenated polymer, and the catalyst (catalyst residue) contained in the reaction mixture is contacted with the oxidizing agent. Preferably. That is, the catalyst in the system after the completion of the hydrogenation reaction is in a reduced state, and is oxidized by bringing it into contact with an oxidizing agent. The oxidation treatment allows the hydrogenation catalyst to be separated more efficiently.

 The oxidizing agent is not particularly limited as long as it has catalytic oxidizing ability, and examples thereof include air (oxygen); and peroxides such as hydrogen peroxide, peracetic acid, and perbenzoic acid; and the like. Air, hydrogen peroxide, more preferably hydrogen peroxide.

 The use amount of these oxidizing agents is not particularly limited, and is 1 to 100 times, preferably 3 to 50 times the mol of the platinum group element contained in the catalyst used for the hydrogenation reaction. The contact temperature is usually 0 to 100 ° C, preferably 50 to 95 ° C, and more preferably 70 to 90 ° C. The contact time is usually 10 minutes to 20 hours, preferably 30 minutes to 10 hours.

 The method of contact between the catalyst and the oxidizing agent is not uniform depending on the type of the oxidizing agent. For example, when air is used as the oxidizing agent, a method of continuously blowing air into the reaction mixture in an open state; open or closed A method in which the atmosphere of the gaseous part of the reaction mixture container in the state is air, and the reaction mixture is stirred. When hydrogen peroxide is used, it may be added to the reaction mixture and stirred.

 After completion of the hydrogenation reaction, a complexing agent is added in the form of a powder or a solution, with or without the above-mentioned oxidizing agent treatment. The complexing agent is brought into contact with the platinum group element to form a complex, which is deposited in the latex and grown or aggregated to a particle size larger than the polymer particles. It is preferable to take the steps of standing still and cooling. The latex pH at the time of complex formation is preferably adjusted to about 8 to 10.5.

The complexing agent is not particularly limited as long as it forms a water-insoluble complex with the platinum group element, but a water-insoluble complex having a strong self-aggregating property is preferable. Specifically, for example, a compound of the formula x, and a compound of the formula x is preferable in view of the strength of the complex-forming ability, and α, j8-alkanedione such as dimethyl dali xylene, cyclohexanedi x dixylene, etc. Zhiximum is more preferred. Among them, dimethyl dalioxime is most preferred. The amount of the complexing agent to be used is generally 1 to 50 times, preferably 2 to 30 times, mol per mol of the platinum group element of the catalyst used. Precipitates that precipitate in latex by adding a complexing agent and have a particle size larger than the polymer particles are removed from the latex by a known simple separation operation such as filtration or eccentric separation, and recovered. Is done. For example, when filtering the precipitate, the filtration device and the filtration method are not limited except that a filter medium that passes only the latex but does not pass the precipitate is used. Both vacuum filtration and pressure filtration can be employed. The catalyst thus recovered as a precipitate can be subjected to a regeneration treatment as needed, and then used for a hydrogenation reaction.

 If desired, the reaction mixture containing the complex can be contacted with the adsorbent after completion of the complexing treatment in order to further increase the separation efficiency. Examples of the adsorbent include activated carbon; silicon-containing inorganic compounds such as diatomaceous earth, talc, clay, activated clay, and silica; activated alumina; synthetic zeolites such as radiolite; and ion-exchange resins. Of these, activated carbon and silicon-containing inorganic compounds are preferred. The adsorption treatment can be carried out by adding an adsorbent to the reaction mixture containing the complex, stirring and mixing the mixture, or passing the reaction mixture through a column filled with these adsorbents.

 The adsorbent that has adsorbed the complex can be removed from the reaction mixture by a known separation operation such as filtration or centrifugation.

 As the filtration device, a filtration device having a structure in which a plurality of filter elements are housed in a sealable housing is usually used. Here, the “filter element” includes a filter element alone or a combination of a filter medium and a filter plate, and refers to the entire member having the “filtration J function” of the filtration device.

 From the viewpoint of the filtration area and the filtration rate, the filter device preferably has a filter element having a cylindrical or hollow disk shape, and the number thereof is preferably 5 or more, and more preferably 10 or more.

The filter element of the filtration device has a structure that allows passage of the hydrogenated conjugated polymer latex but does not allow passage of the water-insoluble complex. Specifically, a filter medium having pores of such a size is used. Materials include natural fibers, synthetic fibers, metals, synthetic resins, and ceramics. These filter media may be used in combination. The filter plate of the filter element is made of metal or synthetic resin from the viewpoint of strength etc. Is preferred. The metal is preferably stainless steel, and the synthetic resin is preferably reinforced polypropylene resin, polyvinylidene fluoride resin, polyphenylene sulfide, or the like. It is preferable that the housing of the filtration device is of a closed type that is connected to the outside only by a housing hole for introducing a substance to be filtered and for extracting a filtrate.

 In the above filtration device, the reaction mixture as the substance to be filtered is filled into the housing through the housing hole through the pipe. The inside of the housing is pressurized by filling the reaction mixture, the reaction mixture is filtered as it passes through the filter element, and the filtrate (latex) is taken out. Then, the water-insoluble complex of the platinum group element is captured on the filter element.

 Examples of the above-mentioned filtration device include those generally known as a pressurized filter which is called a funda-back filter or a leaf filter.

 An example of a leaf filter provided with a hollow disk-shaped filter element is shown in FIG. The housing 1 has a sealed structure in which the inlet 2 for the reaction mixture containing the complex and the filtered latex communicates with the outside only through the outlet 3. The reaction mixture containing the complex flows in the direction of the arrow. That is, the reaction mixture is introduced from the inlet 2, and the latex passes through the leaf filter 4, passes through the core 6 through the core hole 5, and is discharged from the outlet 3.

 The insoluble complex of the platinum group element captured on the filter element is washed off from the filter element by passing air or the like through the filter element in the direction opposite to the filtration direction, and collected together with the filter aid. Can be.

 For efficient filtration without clogging, the filter element can be pre-coated with a filter aid such as diatomaceous earth. Specifically, the suspension of the filter aid is filled in the housing before the supply of the substance to be filtered, and the suspension is filtered to form a pre-coat layer of the filter aid on the filter element. Form.

In the production method of the present invention, as a result of employing the above-mentioned steps of separating and recovering the platinum group element catalyst, a hydrogenated conjugated gen-based polymer latex from which the platinum group element catalyst can be almost removed is obtained. The recovery rate of the platinum group element is at least 70% based on the platinum group element used in the hydrogenation reaction, and about 95% or less depending on the conditions selected. Can be on. The content (remaining amount) of the platinum group element in the latex is usually 300 ppm or less. If the conditions are properly selected, the amount of catalyst can be significantly reduced, and the content of the platinum group element per polymer is 100 ppm or less, preferably 80 ppm or less, more preferably 5 ppm or less. A hydrogenated conjugated gen-based polymer latex of 0 ppm or less can be obtained.

 In order to separate the hydrogenated polymer rubber from the hydrogenated conjugated polymer latex obtained by the production method of the present invention into a rubber product, a method generally used in industry may be appropriately employed. . For example, add a coagulant such as aluminum sulfate, magnesium sulfate, calcium chloride, etc. to the polymer latex to obtain crumbs, wash with water if necessary, and then dry such as draining, hot air drying, drying under reduced pressure or extrusion drying. Through the steps, a hydrogenated conjugated gen-based polymer rubber can be obtained.

 The separated platinum group element-containing catalyst and its complex can be recovered and reused by dissolving, decomposing, reacting, etc.

 Example

 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Parts and percentages in these examples are by weight unless otherwise specified.

 The hydrogenation rate of the hydrogenated conjugated polymer was measured by proton NMR. The amount of palladium in the hydrogenated conjugated polymer rubber was determined by atomic absorption analysis after dissolving a part of the hydrogenated polymer rubber in sulfuric acid after carbonizing it at 600 ° C. It was measured. The hydrogenated polymer rubber whose palladium amount was measured was obtained by concentrating and drying the entire amount of the hydrogenated polymer latex using a rotary evaporator. Are the same.

 Example 1

Two parts of potassium oleate, 180 parts of ion-exchanged water, 37 parts of acrylonitrile, and 0.5 part of t-dodecylmercaptan were sequentially charged into a crepe crepe. After replacing the inside of the reactor with nitrogen, 63 parts of butadiene were sealed. The reactor was cooled to about 0 ° C., and 0.01 part of peroxide of cumene hydride and 0.01 part of ferrous sulfate were added. Next, the reactor was stirred for 16 hours while maintaining the reactor at 10 ° C, and the contents were mixed well. Thereafter, the polymerization was stopped by adding a 10% aqueous solution of octaidoquinone into the reactor. The polymerization conversion was 90%. Unreacted monomers were removed from the polymerization reaction solution to obtain an acrylonitrile-butadiene copolymer (NBR) latex to be subjected to a hydrogenation reaction.

 Palladium acetate (the amount used is 800 ppm in the ratio of Pd metal / NBR described above) and nitric acid in an amount of 5 times the molar equivalent of palladium are added to an acidic aqueous palladium solution (300 mI) to obtain a weight-average solution. Polyvinylpyrrolidone having a molecular weight of 500,000 was added at 5 times the weight of palladium. Further, a potassium hydroxide aqueous solution was added to prepare a catalyst aqueous solution A having a pH of 9.0.

 400 ml of the above-mentioned NBR latex (solid content: 120 g) adjusted to a total solid concentration of 30% and the entire amount of the catalyst aqueous solution A were put into an autoclave equipped with a stirrer, and nitrogen gas was allowed to flow for 10 minutes. The dissolved oxygen in the latex was removed. After the inside of the system was replaced twice with hydrogen gas, 3 MPa of hydrogen was pressurized. The contents were heated to 50 ° C. and reacted for 6 hours to obtain a hydrogenated NBR reaction mixture in a latex state.

 Next, the pH of the above reaction mixture (latex) was adjusted to 9.5, and dimethyldalioxime corresponding to 5 times the molar amount of palladium contained in the aqueous catalyst solution A was added in powder form. Then, the mixture was heated to 80 ° C and stirred for 5 hours. As a result, insolubles were precipitated in the latex. The whole latex was subjected to suction filtration to separate a precipitate. The obtained white filtrate was concentrated under reduced pressure by a rotary evaporator to obtain solid hydrogenated NBR. Hydrogenation The hydrogenation rate of NBR was 93%. The amount of palladium in the hydrogenated NBR was 65 ppm. This amount of palladium was equivalent to 8.1% of the palladium charged to the hydrogenation reaction, and the remaining palladium had been removed from the hydrogenated NBR.

 Comparative Example 1

In the same manner as in Example 1, preparation of NBR (polymerization conversion: 90%), preparation of catalyst solution A, and preparation of hydrogenated NBR latex (hydrogenation 92%) were sequentially performed. The pH of the hydrogenation reaction mixture was adjusted to 9.5, and the mixture was heated to 80 ° C and stirred for 5 hours without adding the dimethyldalioxime powder used in Example 1. During this heating and stirring, there was no change in the state of the reaction mixture (latex), and no precipitate as in Example 1 was observed. When the whole latex was filtered by suction, all of the latex passed through the filter paper. Was. The filtrate had a dark, dark gray color. The obtained filtrate was concentrated under reduced pressure using a rotary evaporator to obtain solid hydrogenated NBR. The amount of palladium in this hydrogenated NBR was 789 ppm. This amount corresponded to 98.6% of the palladium charged to the hydrogenation reaction.

 Example 2

 The same operation as in Example 1 was performed except that the hydroxylating power used in preparing the aqueous catalyst solution A of Example 1 was not used. The hydrogenation rate of the obtained hydrogenated NBR was 65%. The amount of palladium in the hydrogenated NBR was 68 ppm. Equivalent to 8.5% of the palladium charged to the hydrogenation reaction, the remaining palladium had been removed from the hydrogenated NBR.

 Examples 1 and 2 and Comparative Example 明 ら か As is clear from the above, as a post-treatment method after the completion of the hydrogenation reaction, the reaction mixture was treated by adding a complexing agent (dimethyl dalioxime) to the catalyst used. Was confirmed to be efficiently separated.

 Example 3

 Two parts of potassium oleate, 180 parts of ion-exchanged water, 37 parts of acrylonitrile, and 0.5 parts of t-decyl mercaptan were sequentially charged into the crepe. After replacing the inside of the reactor with nitrogen, 63 parts of butadiene were sealed. The reactor was cooled to 10 ° C. and 0.01 part of peroxide at the mouth of cumenehydride and 0.01 part of ferrous sulfate were added. The contents were then stirred for 16 hours while maintaining the reactor at 10 ° C. Thereafter, a 10% aqueous solution of hydroquinone was added to the reactor to terminate the polymerization. Unreacted monomers were removed from the polymerization reaction solution to obtain a latex. The polymerization conversion was 90%. The acrylonitrile-butadiene copolymer (NBR) latex thus obtained was subjected to a hydrogenation reaction in a latex state.

 Palladium acetate (the amount of Pd metal used was 700 ppm based on the NBR ratio) was added to water, and nitric acid was added at a molar equivalent of 5 times the amount of palladium to prepare 300 parts of a palladium acidic aqueous solution. . To this aqueous solution, polyvinyl viridone having a weight average molecular weight of 50,000 was added 5 times by weight with respect to palladium. Further, an aqueous potassium hydroxide solution was added to prepare an aqueous catalyst solution A having a pH of 9.0.

400 parts of the above NBR latex adjusted to a total solid concentration of 30% (solid content Ί2 (0 parts) and the entire amount of the catalyst aqueous solution A were charged into an autoclave equipped with a stirrer, and nitrogen gas was flowed for 10 minutes to remove dissolved oxygen in the latex. After purging the system twice with hydrogen gas, 3 MPa of hydrogen was pressurized. The contents were heated to 50 ° C and stirred for 6 hours to carry out a hydrogenation reaction to obtain a hydrogenated NBR reaction mixture in a latex state.

 To the reaction mixture in the latex state, 2 parts of a 30% aqueous hydrogen peroxide solution was added, and the mixture was stirred (oxidation treatment) at 80 ° C for 2 hours. Next, the pH of the reaction mixture was adjusted to 9.5, and dimethyldalioxime corresponding to 5 times the molar amount of palladium contained in the catalyst aqueous solution A was added as a powder. When the reaction mixture was stirred at 80 ° C for 5 hours (complexation treatment), insolubles were precipitated in the latex. The whole latex was subjected to suction filtration to separate a precipitate. The obtained white filtrate was concentrated under reduced pressure with a rotary evaporator to obtain solid hydrogenated NBR. Hydrogenation The hydrogenation rate of NBR was 93%. The amount of palladium in the hydrogenated NBR was 37 ppm. This amount of palladium corresponded to 5.2% of the palladium charged in the hydrogenation reaction, and the remaining palladium had been removed from the hydrogenated NBR.

 Comparative experiment 1

 In order to examine the effect of performing the oxidation treatment prior to the complexation treatment of the hydrogenation reaction mixture in the method of Example 3 above, a comparative experiment without the oxidation treatment was performed as follows. That is, the preparation of NBR (polymerization conversion: 90%), the preparation of the aqueous catalyst solution A, and the hydrogenation reaction in the latex state (hydrogenation: 92%) were sequentially performed in the same manner as described above. The pH of the reaction mixture was adjusted to 9.5 without adding the aqueous hydrogen peroxide solution, and the mixture was stirred at 80 ° C. for 7 hours. The amount of palladium in the hydrogen hydride NBR finally obtained was 58 ppm.

 As is clear from the above Example 3 and Comparative Experiment 1, it can be seen that the content of palladium in the obtained hydrogenated NBR differs depending on whether or not an oxidation treatment is performed as a post-treatment method after completion of the hydrogenation reaction. It was confirmed that the catalyst used for the hydrogenation reaction can be more efficiently separated from the reaction mixture by performing the oxidation treatment.

 Comparative experiment 2

In the method of Example 3 above, a comparative experiment was conducted as described below to examine the effect of the hydrogenation catalyst stabilizer (polyvinylpyrrolidone) added prior to the hydrogenation. In addition, as a result of separately evaluating the storage stability of the same catalyst aqueous solution A to which the hydrogenation catalyst stabilizer (polyvinylpyrrolidone) was used, which was used for hydrogenation in Example 3 above, the storage stability was 25 ° C. No aggregation or precipitation was observed at all even after standing for a day.

 For comparison, the hydrogenation reaction and the recovery of the hydrogenated polymer were performed in the same manner as in Example 3 except that polyvinylpyrrolidone was not added to the aqueous hydrogenation catalyst solution A used in the method of Example 3 above. Was performed. Hydrogenation The hydrogenation rate of NBR reached only 70%. As a result of evaluating the storage stability of the catalyst aqueous solution A to which polyvinylpyrrolidone was not added, a slight precipitate was observed when the catalyst aqueous solution A was allowed to stand at 25 ° C for 1 hour.

 As is clear from Example 3 and Comparative Experiment 2 described above, when no catalyst stabilizer was used in the hydrogenation reaction, the hydrogenation rate of the hydrogenated conjugated gen-based polymer was reduced to 90%. In addition, the catalyst settled or precipitated when the aqueous catalyst solution was stored for a long period of time. In contrast, when the hydrogenation reaction was carried out in the presence of a catalyst stabilizer, the hydrogenation rate of the hydrogenated conjugated polymer reached 90% or more, and the catalyst aqueous solution was stored for a long time. Was still uniformly dissolved.

 Example 4

 Hydrogenation was performed in the same manner as in Example 1 to obtain a hydrogenated NBR reaction mixture in a latex state. To this reaction mixture was added 30% aqueous hydrogen peroxide solution, and the mixture was stirred (oxidation treatment) at 80 ° C for 2 hours. Next, the pH of the reaction mixture (latex) was adjusted to 9.5, and dimethyldarylic acid equivalent to 5 times the molar amount of palladium contained in the catalyst aqueous solution A was added as powder. Then, when the mixture was heated to 80 ° C. and stirred for 5 hours, insolubles were precipitated in the latex.

The reaction mixture containing the insolubles was filtered using a FUNDABAC filter (trade name: FUNDABAC, manufactured by Ishikawajima-Harima Heavy Industries, Ltd.). The fundaback filter has a large number of cylindrical filter elements (16 to 18 depending on the model) in a sealable housing. Each filter element has a tubular filter plate covered with a filter cloth. The tubular filter plate consists of a candle piece through which the filtrate flows and a riser pipe in the center where the filtrate collects. After filtering the radiolite into the filter element with the radiolite (diatomaceous earth) suspension, pressure filtration was performed.

 The obtained white filtrate was concentrated under reduced pressure by a rotary evaporator to obtain solid hydrogenated NBR. Hydrogenation The hydrogenation rate of NBR was 93%. The amount of palladium in the hydrogenated NBR was 40 ppm. Also, the amount of palladium lost due to leakage during filtration and attachment to the housing wall was only 1% of the amount used for the hydrogenation reaction.

 Example 5

 The same operation as in Example 4 was performed except that the filtration was performed using a leaf filter (Ishikawajima-Harima Heavy Industries, Ltd., see FIG. 1). The leaf filter has one or two disc-shaped filter elements (three in Fig. 1), which are attached to a cylindrical core passing through the center. One end of the cylindrical core is closed, and the other end is opened to the outside through the wall of the housing. At least one core hole is provided in each of the filter element mounting portions, and the filter element is filtered. The collected filtrate is collected and taken out. The filter media of each filter element is a stainless steel wire mesh. Precoating with a radio light was performed in the same manner as in Example 4. The time required to obtain the same amount of filtrate as in Example 4 was the same as in Example 4.

 The amount of palladium in the obtained hydrogenated NBR was 40 ppm. The amount of palladium lost due to leakage during filtration and adhesion to the housing wall was 3% of the amount used for the hydrogenation reaction.

 Comparative experiment

 In order to investigate the effect of the filtration device having a plurality of filter elements used in Example 4 and Example 5, the following comparative experiment was performed using a filtration device having a single filter element.

 That is, the same operation as in Example 4 was performed except that the filtration was performed using a membrane filter (manufactured by Millipore) having only one filter element covered with a polytetrafluoroethylene membrane as a filtration device. Pre-recording by radio was not performed.

The amount of palladium in the obtained hydrogenated NBR was 40 ppm. Due to clogging, the filter element was replaced once. In addition, the time required to obtain the same amount of filtrate as in Example 4 was twice as long as that in Example 4. As a result, the loss of palladium was 15% of the amount used in the hydrogenation reaction.

 As is clear from Examples 4 and 5 and the comparative experiment, when filtration is performed using a membrane filter having only one filter element, the filtration speed decreases, clogging occurs, and catalyst Loss is also large. On the other hand, it was confirmed that if filtration was performed using a filtration device having a plurality of filter elements, the used catalyst could be efficiently separated without loss, and a polymer with a small residual amount of palladium was obtained. Industrial applicability

 The latex of a hydrogenated conjugated diene polymer produced by the method of the present invention and having a reduced content of a platinum group element is useful as an adhesive, a coating agent, a paint, a raw material for dip-molded bag, and the like. Since the amount of residual platinum group elements in latex is significantly reduced, when used as an adhesive, coating agent, paint, etc., the corrosion resistance of the adhered or coated metal material is high, and the residual platinum group elements Since there is no darkening caused by paint, coatings and paints have a high degree of freedom in coloring. Further, gloves obtained by dip-forming latex are suitable for work such as a semiconductor device manufacturing process.

 The hydrogenated conjugated polymer rubber obtained from the hydrogenated conjugated polymer latex is derived from the platinum group element because the content of the platinum group element per polymer is 100 ppm or less. It has no fear of darkening or coloring and can be used in a wide range of industrial applications that make use of various properties such as oil resistance, weather resistance, ozone resistance, heat resistance, and cold resistance.

 Also, the separated platinum group element-containing catalyst and its complex can be recovered by dissolution, decomposition, reaction treatment, etc., and reused.

Claims

 The scope of the claims 1-Latex of a hydrogenated conjugated polymer having a content of platinum group element per polymer of Ί100 ppm or less.  2. The latex of the hydrogenated conjugated gen-based polymer according to claim 1, wherein the content of the platinum group element per polymer is 80 ppm or less.  3. The latex of the hydrogenated conjugated gen-based polymer according to claim 1, wherein the content of the platinum group element per polymer is 50 ppm or less.  4. The hydrogenated conjugated gen-based polymer is a homopolymer or a hydride of at least one conjugated gen monomer, or the at least one conjugated gen monomer and another copolymer. 4. The latex of a hydrogenated conjugated gen-based polymer according to any one of claims 1 to 3, which is a hydride of a copolymer with a possible monomer.  5. The hydrogenated conjugated diene polymer is a hydride of a copolymer of a conjugated diene monomer and an α,; 8-unsaturated ethylenic ditolyl monomer. A latex of the hydrogenated conjugated gen-based polymer according to any one of the above.  6. The hydrogenated conjugated diene polymer is a hydride of a copolymer of 1,3-butadiene 30 to 95% by weight and acrylonitrile 5 to 70% by weight. A latex of the hydrogenated conjugated gen-based polymer according to any one of the above.  7. A hydrogenated conjugated gen-based polymer rubber obtained by separating from the polymer latex according to claim 1 and having a platinum group element content of 100 ppm or less.  8. A hydrogenated conjugated gen-based polymer rubber obtained by separating from the polymer latex according to claim 2 and having a platinum group element content of 80 ppm or less.  9. A hydrogenated conjugated polymer rubber having a platinum group element content of 50 ppm or less, obtained by separating from the polymer latex according to claim 3. 10. A hydride of a homopolymer or copolymer of at least one conjugated diene monomer, or a copolymer of the at least one conjugated diene monomer and another copolymerizable monomer The hydrogenated conjugated gen-based polymer rubber according to any one of claims 7 to 9, comprising a combined hydride. 11. The hydrogenated conjugated gel according to any one of claims 7 to 9, comprising a hydride of a copolymer of a conjugated diene monomer and a,) 8-unsaturated ethylenic nitrile monomer. Polymer rubber.  12. The hydrogenation conjugated gene according to any one of claims 7 to 9, comprising a hydride of a copolymer of 30 to 95% by weight of 1,3-butadiene and 5 to 70% by weight of acrylonitrile. -Based polymer rubber.  1 3. Dissolve or disperse a hydrogenation catalyst containing a platinum group element compound in a conjugated polymer latex to hydrogenate carbon-carbon unsaturated bonds of the polymer, A method for producing a hydrogenated conjugated gen-based polymer latex, comprising separating a precipitate formed by adding a complexing agent that forms a water-insoluble complex with a platinum group element to a combined latex.  1 4. The conjugated diene polymer is a homopolymer or copolymer of at least one conjugated diene monomer, or the at least one conjugated diene monomer and another copolymerizable monomer 14. The production method according to claim 13, which is a copolymer with  15. The process according to claim 13 or 14, wherein the conjugated gen-based polymer is a copolymer of a conjugated gen monomer and an α, / 3-unsaturated ethylenic nitrile monomer. Method.  16. The claim 13 or 14 wherein the conjugated gen-based polymer is a copolymer of 30 to 95% by weight of 1,3-butadiene and 5 to 70% by weight of acrylonitrile. Manufacturing method described in.  1 7. The production method according to any one of claims 13 to 16, wherein the platinum group element is palladium.  18. The production method according to any one of claims 13 to 17, wherein the hydrogenation is performed under basic conditions.  1 9. The production method according to any one of claims 13 to 18, wherein the complexing agent is a compound of the formula. 20. Prior to hydrogenation, a polymer compound having a weight-average molecular weight of 1,000 to 100,000, which is soluble or dispersible in a conjugated diene polymer latex, The production method according to any one of claims 13 to 19, wherein 0.5 to 20 times by weight of the metal element in the hydrogenation medium is added as the hydrogenation catalyst stabilizer.  21. The production method according to claim 20, wherein the polymer compound is a polymer or polyether of a vinyl compound having a polar group in a side chain.  2. An oxidizing agent is added to the latex of the hydrogenated polymer before or simultaneously with the addition of the complexing agent, and the catalyst residue contained in the latex is brought into contact with the oxidizing agent. 3. The production method according to any one of 3 to 2 above.  23. The method according to claim 22, wherein the oxidizing agent is air or hydrogen peroxide.  24. The precipitate according to any one of claims 13 to 23, wherein the precipitate formed by adding the complexing agent is separated by filtration using a filtration device having a plurality of filter elements. Production method.  25. The production method according to claim 24, wherein a plurality of cylindrical or hollow disk-shaped filter elements housed in a sealable housing are used.