JP2004307603A - Polymer purification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer purification method capable of efficiently removing metallic components from a polymer solution containing the metallic components. <P>SOLUTION: A polymer solution of which the temperature is 40-200°C and of which the partial pressure of dissolved hydrogen at that temperature is 0.1-10 MPa is brought into contact with an adsorbent, yielding a polymer containing a catalyst-derived metal in a content of 50 ppb or lower. Purification by this method remarkably decreases the metal content in a polymer having a polar structure or an aromatic ring structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００５１】
表１が示すように、合成例１及び２にて、極性基であるヒドロキシカルボニル基を有するノルボルネン系単量体を、それぞれルテニウム含有触媒で開環重合及び水素化して得た単独重合体及び共重合体について、それぞれの溶液に活性炭を添加して、１５０℃にて水素を４ＭＰａで３時間溶存させてから活性炭をろ別したところ、いずれも重合体中の触媒由来の金属ルテニウム含有量は極めて少なく、また、環境由来のその他の金属も検出限界以下であった（実施例１及び２）。また、合成例１で得た単独重合体の水素化前の重合体溶液について、水素を溶存させる温度を１５０℃から６０℃に低下することにより、重合体を水素化させないで、金属含有量を極めて少なくすることができた（実施例３）。
一方、上記単独重合体の溶媒溶液に活性炭を添加して温度１５０℃にて３時間撹拌しても、該溶液に水素を溶存させずにろ過して得られた重合体では金属の低減が認められなかった（比較例１）。
また、水素に代えて窒素を用いたほかは実施例１と同様に行っても、いずれも重合体の金属含有量は大きかった（比較例２及び３）。
【００５２】
【発明の効果】
本発明の精製方法によると、重合体に残留する、触媒に由来する金属のみならず、金属製反応器や他の反応資材など環境から混入する金属も大幅に削減できる。
こうして本発明の精製方法によって精製された重合体は、金属をほとんど含まないので、半導体製造用電気絶縁膜、表示素子用カバー膜、封止膜などの電子部品；光ディスク、呼応額フィルム、レンズなどの光学製品などに好適に使用することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for purifying a polymer, and more particularly, to a method for purifying a polymer that can obtain a polymer having an extremely small metal content.
[0002]
[Prior art]
Synthetic resins such as acrylic resins, phenolic resins, and alicyclic olefin resins are widely used in the fields of electrical insulating films and resists for semiconductor manufacturing; transparent cover films for liquid crystal display devices; It has been pointed out that in order to improve the resistance, electric noise and transparency hindrance caused by metal remaining in the resin are problems. In the use of the semiconductor and the transparent molded article, it is required that the metal content in the resin is 1 ppm or less. However, in a polymer such as a resin, a metal component derived from a metal-containing catalyst used in a step of preparing a polymer such as a polymerization reaction and a polymer modification reaction; mixed from a reactor, a dryer, a transfer pipe, and the like. Metal components derived from the environment; Among such residual metals, a large amount of a metal component derived from a metal-containing catalyst used in the process of preparing a polymer such as a polymerization reaction or a hydrogenation reaction on a carbon-carbon double bond of the polymer, It is important to remove them.
[0003]
A method of contacting a polymer solution comprising a polymer, a metal component, and an organic solvent with an adsorbent to adsorb and remove a metal component remaining in the polymer has been studied. In Patent Document 1, after performing ring-opening (metathesis) polymerization of a norbornene-based monomer or a cycloalkene derivative with a metal alkylidene catalyst (metal is ruthenium or osmium), a metal-containing catalyst remaining in a polymer solution is converted to a vinyl compound. Then, a method is proposed in which the polymer solution is contacted with an adsorbent to adsorb and remove the residual metal in the polymer. Then, as a method of bringing the polymer solution into contact with the adsorbent, a packed layer of the adsorbent is formed in a funnel, a filter or a column, and atmospheric pressure filtration, suction filtration, pressure filtration with air or an inert gas, column Separation and the like are exemplified. In the examples, a method by suction filtration using an activated alumina packed bed is described. However, even when purification is performed by this method, the amount of metal remaining in the polymer can be reduced to at most about 200 ppm.
[0004]
[Patent Document 1]
JP 2001-163958 A
[0005]
[Problems to be solved by the invention]
In view of the above circumstances, an object of the present invention is to provide a method for purifying a polymer that can efficiently remove a metal component from a polymer solution containing the metal component.
[0006]
[Means for Solving the Problems]
The present inventors have widely studied a method of recovering a catalyst from a polymer obtained by a reaction using a metal-containing catalyst, and as a result, in particular, a catalyst residue from a polymer obtained through a reaction using a homogeneous metal-containing catalyst. It has been found that it is difficult to remove the metal derived from the catalyst when the polymer is separated, and that the tendency is particularly remarkable in the case of a polymer having a polar structure or an aromatic ring structure.
Accordingly, the present inventors have focused on research on a method of separating a catalyst from a solution having a polymer having a polar structure or an aromatic ring structure and a metal-containing homogeneous catalyst, and as a result, have found that a solution of the polymer in which hydrogen is dissolved is obtained. When contacted with an adsorbent, it was found that the catalyst adsorbed well on the adsorbent, facilitated filtration, and reduced not only metal derived from the catalyst but also metals mixed in from the environment such as sodium mixed in from the environment. The present invention has been completed based on the findings.
[0007]
Thus, the present invention provides the following 1 to 6.
1. A method for purifying a polymer, comprising bringing a polymer solution containing a polymer, a metal component, and an organic solvent into contact with an adsorbent, wherein the temperature of the polymer solution is 40 to 200 ° C, and the temperature of the polymer solution is A method for purifying a polymer wherein the partial pressure of dissolved hydrogen is 0.1 to 10 MPa.
2. 2. The method for purifying a polymer according to the above 1, wherein the polymer has a polar structure or an aromatic ring structure.
3. 2. The method for purifying a polymer according to the above 1, wherein at least one of the metal components is a metal-containing homogeneous catalyst used for obtaining the polymer.
4. 4. The method for purifying a polymer according to the above item 3, wherein the genus-containing homogeneous catalyst is a catalyst containing a platinum group atom.
5. The polymer solution is prepared by heating a solution containing a polymer, a metal component and an organic solvent to 40 to 200 ° C in an environment having a hydrogen partial pressure of 0.1 to 10 MPa. A method for purifying a polymer.
6. A polymer obtained by the method for purifying a polymer according to any one of the above 1 to 5, wherein the metal content derived from the catalyst used to obtain the polymer is 50 ppb or less.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the polymer solution to be brought into contact with the adsorbent is, of course, one containing a polymer, a metal component, and an organic solvent, but further, the polymer solution is heated to a predetermined temperature, It also dissolves hydrogen at a specific hydrogen partial pressure. Hereinafter, such a polymer solution that is brought into contact with the adsorbent according to the present invention may be referred to as a “hydrogen-dissolved polymer solution”.
The hydrogen-dissolved polymer solution is usually obtained by dissolving hydrogen in a polymer solution in which a polymer and a metal component are dissolved in an arbitrary organic solvent.
[0009]
The polymer used in the present invention is not particularly limited, but a polymer obtained by using a metal catalyst described in detail below is preferable. Of course, even in the case of a polymer produced without using a metal catalyst, the method of the present invention can be employed to remove environmentally-derived metal components mixed in the production process.
The metal component to which the present invention is applied is not limited as long as the metal component is present in the solution together with the polymer.For example, the metal component is derived from a metal catalyst such as a metal-containing homogeneous catalyst used for preparing the polymer. Components and metals derived from the environment. Also, it does not matter whether it is in a dissolved state or a precipitated state.
The organic solvent used in the present invention may be any organic solvent that is industrially used as a general organic solvent that is liquid at room temperature, and includes, for example, an organic solvent used for preparing a polymer.
[0010]
The polymer solution containing a polymer, a metal component and an organic solvent may be prepared by any method, for example, a polymer reaction solution itself obtained in the presence of a metal-containing catalyst, The dried polymer may be dissolved in a new solvent.
When the polymer solution is a reaction solution after the polymerization reaction, any solvent can be added to adjust the solid content concentration, and a part of the solvent in the solution is evaporated. You can also. The solvent to be added is not limited as long as it dissolves the polymer.If the solvent is the same as the organic solvent constituting the reaction solution, the organic solvent is recovered, so that purification becomes easy when reused. preferable.
[0011]
There is no particular limitation on the method of dissolving hydrogen in the polymer solution.For example, a method of pressurizing a heated polymer solution containing a polymer and a metal component under a hydrogen atmosphere using a pressurizing device, or a method of heating And a method of bubbling hydrogen gas into the polymer solution.
Even in the method using a pressurizing device, even in the method of bubbling, the temperature of the polymer solution may be set in consideration of the solubility of hydrogen and the stability of the polymer solution, but is usually 40 to 200 ° C., preferably 50-180 ° C. In addition, when a pressure device is used or when bubbling is used, the hydrogen pressure applied to the polymer solution is usually 0.1 to 10 MPa, preferably 1 to 10 MPa, more preferably 1 to 8 MPa as a hydrogen partial pressure. The time required to dissolve hydrogen in the polymer solution depends on the dissolution method, type of polymer and organic solvent, amount of polymer solution, solid concentration of polymer solution, temperature of polymer solution, applied pressure, etc. However, since the amount of hydrogen that can be dissolved in a normal polymer solution is limited, it is usually 5 minutes to 10 hours, preferably 30 minutes to 5 hours from the viewpoint of productivity.
The solid content concentration of the hydrogen-dissolved polymer solution can be arbitrarily selected depending on the method of contact with the adsorbent, but is usually 5 to 80% by weight, preferably 10 to 50% by weight. If the polymer concentration is too low, the efficiency of removing the metal-containing homogeneous catalyst may be reduced, which may be uneconomical. On the other hand, if the polymer concentration is too high, the contact with the adsorbent may not be sufficiently performed.
[0012]
In the present invention, the metal is removed from the polymer by bringing such a hydrogen-dissolved polymer solution into contact with an adsorbent.
Examples of the adsorbent include known ones that can be used to remove residual metals in the polymer, for example, activated carbon; graphite; metal oxide gels; clay intercalation compounds; Further, the used adsorbent can be reused after desorption treatment.
[0013]
As the activated carbon, commercially available activated carbon powder or granulated activated carbon can be used. It is preferable to remove these by washing with water, washing with an acid, washing with an alkali, washing with an organic solvent, etc. to remove impurity components and foreign substances adhering to the surface, and then use them after drying.
[0014]
As the graphite, either natural graphite or artificial graphite may be used. Graphite is known to form an intercalation compound with an alkali metal or a metal halide, and when applied to a resist or a solution of a composition thereof, an impurity metal component can be reduced extremely efficiently. However, similarly to activated carbon, it is preferable to sufficiently wash and dry before use.
Examples of the metal oxide gel include silica gel, alumina gel, and alumino silica gel.
[0015]
Examples of clay intercalation compounds include fluorite, shale, boraxite, kaiju fluorite, mordenite, dakialdudofluorite, kifulite, clinoptiroluffite, Brewster fluorite, dakufuite, ryokuchuite, kinseiite, kasumiite. Zeolites such as zeolite A; synthetic zeolites; kaolinite, antigorite, deckite, chrysotile, naclite, pyrosite, pyrophyllite, montmorillonite, talc, vermiculite, muscovite, Phlogopite, margarite, zansophyllite, chlorite and the like.
[0016]
There is no particular limitation on the method for bringing the polymer solution into contact with the adsorbent, and examples thereof include a method A for adding the adsorbent to the polymer solution and a method B for flowing the polymer solution contacted with hydrogen through the adsorbent layer. Can be The time for bringing the hydrogen-dissolved polymer solution into contact with the adsorbent varies depending on the solid concentration and amount of the solution, the contact method, the type and amount of the adsorbent, etc., but usually 10 minutes to 10 hours, more preferably 30 minutes to 5 hours.
[0017]
In the method A, the adsorbent may be added to the solution after the hydrogen is completely dissolved (hydrogen-dissolved polymer solution) or the polymer solution before the hydrogen-dissolved polymer solution (polymer This may be performed before dissolving hydrogen in the solution or on a polymer solution in the process of dissolving hydrogen. When the adsorbent is added to the polymer solution before the hydrogen-dissolved polymer solution is formed, it is necessary to dissolve hydrogen in the polymer solution after the addition of the adsorbent by the above-described method or the like. After the adsorbent is added to the polymer solution, the adsorbent can be circulated in the solution by stirring or the like. The addition amount of the adsorbent is preferably 0.1 to 100 parts by weight, more preferably 0.5 to 50 parts by weight, particularly preferably 1 to 30 parts by weight, per 100 parts by weight of the polymer. If the amount of the adsorbent is too small, the metal content of the polymer may not be reduced much. Conversely, if the amount is too large, the filtration may take a long time and the productivity may be reduced.
[0018]
When the hydrogen-dissolved polymer solution is brought into contact with the adsorbent, it is preferable to continuously or intermittently add hydrogen to the hydrogen-dissolved polymer solution at 40 to 200 ° C at a pressure of 0.1 to 10 MPa.
When the polymer to be purified is a polymer modified by hydrogen, for example, when the polymer is a polymer having a carbon-carbon double bond, hydrogenation of a carbon-carbon double bond as a metal component ( If a metal-containing catalyst that functions as a catalyst for the (hydrogenation) reaction is included, the polymer is hydrogenated. In order to purify the polymer without causing a side reaction (for example, a hydrogenation reaction of the polymer) as described above, hydrogen is dissolved in the solution at a temperature of 100 ° C. or lower, and an adsorbent is added to the polymer solution. It is preferable to adopt a method such as dissolving hydrogen.
[0019]
When the method A of adding the adsorbent to the solution is adopted, it is necessary to remove the adsorbent after the contact treatment (solid-liquid separation). Filtration is common as a solid-liquid separation means. The filtration device is not limited as long as it performs solid-liquid separation by a filter. Examples of the filter material include a leaf filter having a wire mesh such as non-cast steel and Monel metal; a filter cloth made of fiber such as polyamide, polyester, and wool; a strainer made of synthetic resin such as polyfluorinated polypropylene and polycarbonate. The driving force for solid-liquid separation may be any of centrifugal force, pressurization, decompression, gravity, and the like. Moreover, a batch type or a continuous type provided with a cake scraping blade may be used.
Prior to this filtration, the adsorbent is adsorbed using a centrifugal separator such as a cylindrical centrifuge, a conical centrifuge, a clarifier, and a separator centrifuge to prevent clogging of the filter. Most can also be removed by settling out. In order to increase the removal rate of the adsorbent in the centrifugation, the viscosity of the polymer solution applied to the centrifugal separator is preferably 1 Pa · s or less, more preferably 0.5 Pa · s or less, particularly preferably 0.3 Pa · s or less.・ Adjust to s or less. A solvent can be added to the polymer solution after the contact treatment for adjusting the viscosity. It is preferable that the solvent to be added is the same as the reaction solvent used when preparing the polymer, because the purification is simplified when the polymer is recovered and reused.
[0020]
In the method B of flowing through the adsorbent layer, the adsorbent layer is an adsorbent fixed layer or an adsorbent moving layer. Specifically, a method of flowing a polymer solution through a fixed bed filled with an adsorbent, a method of dropping an adsorbent as a moving bed from above a vertical tower (tube), and flowing a hydrogen-dissolved polymer solution from below. And countercurrent contact.
In the method B, it is preferable from the viewpoint of productivity that the solid content of the hydrogen-dissolved polymer solution be set to a lower level, for example, 5 to 30% by weight in the above-mentioned range of the solid content.
The operation of flowing the hydrogen-dissolved polymer solution through the adsorbent layer can be performed in a batch system or a continuous system.However, when the system is operated in a continuous system, the amount of the adsorbent used is smaller than that in the above reactor addition system. Relatively high. It is usually 10 to 70 parts by weight, preferably 50 to 70 parts by weight, per 100 parts by weight of the polymer. Distribution speed (m³/ Hr-solution flow rate) / (m³-Adsorption layer capacity) is usually 2 to 30 hours.^-1, Preferably 5 to 10 hours^-1It is.
[0021]
When flowing the hydrogen-dissolved polymer solution through the adsorbent fixed bed, a packed tower, a packed vessel, a filled tube, or the like is used as the fixed bed. Initially, when the hydrogen-dissolved polymer solution is passed through the fixed bed, the catalyst is effectively adsorbed at the upstream end of the packed bed, and the rest is adsorbed by the adsorbent immediately downstream of the packed bed. narrow. As the operation proceeds and the adsorbing capacity of the adsorbent in the upstream part is saturated, the downstream end of the adsorption zone moves to the downstream side of the packed bed. When the downstream end of the adsorption zone reaches the downstream end of the packed bed, the packed bed is replaced with a new adsorbent.
[0022]
In the case where the adsorbent is dropped as a moving bed from above a vertically installed tower (tube) as a moving bed, and a hydrogen-dissolved polymer solution is allowed to flow from below to make countercurrent contact, the adsorbent is not used once. Since many adsorption sites remain, they are usually desorbed and repeatedly reused.
In this moving bed method, as a step of separating the adsorbent from the solution, a strainer is provided at the lower end of a tower (tube) to perform solid-liquid separation.
[0023]
The solution that has been brought into contact with the adsorbent is usually subjected to a known treatment such as a coagulation method or a direct drying method to recover the polymer.
The coagulation method is a method in which a polymer solution is mixed with a poor solvent for a polymer to precipitate the polymer. Examples of the poor solvent include alcohols such as ethyl alcohol, n-propyl alcohol, and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; and polar solvents such as esters such as ethyl acetate and butyl acetate.
The polymer crumb obtained by coagulation is subjected to solid-liquid separation by the same centrifugal separator as described above. The separated polymer crumb is then dried by heating, for example, in vacuum or in nitrogen or air, and the melt extruder is added to the particulate polymer or, if necessary, to various additives. And extruded into pellets.
[0024]
On the other hand, the direct drying method is a method in which a polymer solution is heated under reduced pressure to evaporate a solvent. The evaporated solvent is usually recovered by condensing by cooling. For this method, a known drying device such as a centrifugal thin film continuous evaporative dryer, a scraped surface heat exchange type continuous reactor type dryer, and a high viscosity reactor device is used. The degree of vacuum and the temperature are appropriately selected depending on the device, and are not limited.
[0025]
The polymer purified by the purification method of the present invention described above has a metal content derived from the catalyst of 50 ppb or less, more preferably 30 ppb or less, particularly preferably 10 ppb or less, and the other metals are also 10 ppb or less.
Hereinafter, an example of a polymer to which the purification method of the present invention can be adopted will be described in detail, but the purification method of the present invention is not limited thereto.
[0026]
Polymers having a remarkable effect on metal reduction by purification according to the method of the present invention include polymers having a polar structure or an aromatic ring structure.
The polar structure is a halogen atom such as chlorine, bromine or iodine; a monovalent or polyvalent atomic group including a hetero atom having an unshared electron pair such as an oxygen atom, a nitrogen atom or a sulfur atom. Specific examples of the monovalent or polyvalent atomic group containing a hetero atom include an amino group, an N, N-disubstituted amino group, a nitro group, a carbonyl group, a carbonyloxycarbonyl group, a hydroxycarbonyl group, an oxycarbonyl group, and a carboxyl group. Group, formyl group, alkoxy group, ester group, hydroxyl group, glycidyl group, nitrile group, ether group, thioether group, N-substituted amide group, N-substituted imide group; and sulfuric acid group, sulfonic acid group, carboxylic acid group Acid groups such as carboxylic acid anhydride residues, phosphoric acid groups and phosphite groups; and non-aromatic heterocyclic groups such as pyrrolidinyl groups, pyrrolinyl groups and piperidino groups.
In the present invention, the aromatic ring structure is a structure comprising a ring having aromaticity, and the ring having aromaticity (hereinafter, referred to as an aromatic ring) is a benzene ring; a bonded benzene ring such as a naphthalene ring, an anthracene ring, or a phenanthrene ring. A non-benzene-based aromatic ring such as a tropylium ring and a cyclopropenium ring; a group having a heteroaromatic ring such as pyridine, pyrrole, furanol and thiophene; Of course, these aromatic ring structures may have a substituent such as an alkyl group.
[0027]
Examples of the polymer having a polar structure or an aromatic ring structure include a polymer, a polymerization reaction of a monomer, a hydrogenation reaction of the polymer, and a modification of the polymer, which are performed according to a conventional method in the presence of a metal-containing homogeneous catalyst. Those obtained by a reaction, a hydrolysis reaction or the like, and those having a polar structure or an aromatic ring structure may be mentioned. Specifically, for example, alicyclic olefin monomers (norbornene-based monomers, monocyclic cycloalkenes, vinyl alicyclic hydrocarbons, aromatic vinyl monomers, monocyclic conjugated dienes, monocyclic non-conjugated dienes A ring-opened polymer of an alicyclic olefin monomer; an epoxy-modified or maleic acid-modified alicyclic olefin monomer ring-opened polymer or a hydrogenated product thereof; Hydrolyzate of ring-opening polymer of alicyclic olefin monomer; addition polymer of alicyclic olefin monomer; epoxy-modified or maleic acid-modified alicyclic olefin monomer addition polymer; Anion polymer of aromatic vinyl monomer; hydride of anion or radical polymer of aromatic vinyl monomer; anion polymer of conjugated diene monomer; hydride of radical polymer of conjugated diene monomer; Such as a polar structure Or those having an aromatic ring structure. In particular, the polymer of the present invention obtained by using an alicyclic olefin monomer or an aromatic vinyl monomer or a hydrogenated product thereof is particularly effective.
The ratio of the monomer unit having a polar structure or an aromatic ring structure to the total amount of the monomer units constituting the polymer is not particularly limited, but is usually 30% by weight or more, preferably 50% by weight or more. . The effect of the method of the present invention is exerted as the proportion of the monomer unit having a polar structure or an aromatic ring structure increases.
[0028]
The polymer having a polar structure or an aromatic ring structure is described in JP-A-8-20692, JP-A-8-259784, JP-A-10-307388, JP-A-2001-48924, and the like. It can be obtained by a known polymerization reaction using a metal-containing homogeneous catalyst, a hydrogenation reaction, a modification reaction, a hydrolysis reaction, or the like. These reactions are usually performed in an organic solvent in which the above-mentioned catalyst is present.
Examples of the metal-containing catalyst include the following ring-opening polymerization catalyst, addition polymerization catalyst, anion polymerization catalyst, hydrogenation catalyst, and the like.
[0029]
Examples of metal-containing ring-opening polymerization catalysts include platinum group metals such as ruthenium, rhodium, palladium, iridium and platinum; tungsten, molybdenum and rhenium (a); Group 1 atoms (b1) such as lithium, sodium and potassium; magnesium , Calcium and other Group 2 atoms (b2); zinc, cadmium, mercury and other Group 12 atoms (b3); boron and aluminum such as Group 13 atoms (b4); silicon, tin, lead and other Group 15 atoms (b b5) containing one kind of metal atom selected from Group 4 atoms (b6) such as titanium and zirconium; and having at least one of the atom-carbon bond or the atom-hydrogen bond. .
As the metal-containing addition polymerization catalyst, a transition metal compound belonging to Groups 3 to 12 and having a ligand that coordinates to the transition metal with π electrons is used. Particularly preferred examples include an allyl complex of a Group 10 transition metal (nickel, palladium, platinum) and a cyclopentadienyl complex of a Group 4 (titanium, zirconium) or Group 5 transition metal (vanadium, niobium, tantalum). be able to. Here, the groups of atoms are all groups in the long-period periodic table.
The amount of the metal-containing catalyst used for the ring-opening or addition polymerization is such that the molar ratio to the monomer is preferably from 1: 100 to 1: 2,000,000, more preferably from 1: 500 to 1: 1,000,000. 000, particularly preferably 1: 1,000 to 1: 500,000. If the amount of the catalyst is too large, it is difficult to remove the catalyst after the polymerization reaction, and if the amount is too small, sufficient polymerization activity cannot be obtained.
[0030]
Examples of the metal-containing anionic polymerization catalyst include n-butyllithium, sec-butyllithium, t-butyllithium, and hexyllithium. Monoorganic lithium compounds such as phenyllithium and stilbenelithium; polyfunctional organic lithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; sodium Naphthalene, potassium naphthalene and the like can be mentioned. Among these, organolithium compounds are preferred, and monoorganic lithium is particularly preferred. These organic alkali metals can be used alone or in combination of two or more. The amount of the organic alkali metal to be used is generally 0.05 to 100 mmol, preferably 0.10 to 50 mmol, more preferably 0.15 to 20 mmol, per 100 parts by weight of the monomer.
[0031]
As a metal-containing hydrogenation catalyst, a so-called Ziegler-type catalyst in which an organic acid salt such as titanium, cobalt, nickel or the like or an acetylacetone salt is combined with an organic metal compound such as lithium, magnesium, aluminum, tin or the like; ruthenium, rhodium And a noble metal complex catalyst such as rhenium. Some of the ring-opening polymerization catalysts described above can be used as a hydrogenation catalyst. For example, since a catalyst containing a white metal atom has high ring-opening polymerization reaction activity and high hydrogenation activity, for example, after ring-opening polymerization of a norbornene-based monomer, hydrogenation is subsequently performed on the obtained polymer. In such a case, the polymerization catalyst can be used as it is as a hydrogenation catalyst. In particular, among the catalysts containing a white metal atom, those containing ruthenium are preferred, and 1,3-dimesitylimidazolidine-2-ylidene (tricyclohexylphosphine) benzylidene ruthenium dichloride, RuHCl (CO) [P (C₆H₅)₃]₃, RuCl₂[P (C₆H₅)₃]₃, RuH₂(CO) [P (C₆H₅)₃]₃, Ru (CO)₃[P (C₆H₅)₃]₂Such ring-opening polymerization catalysts are highly effective in the present invention.
[0032]
Among the metal-containing catalyst residues, it has conventionally been considered difficult to remove the metal-containing homogeneous catalyst residue because it is dissolved in the polymer solution. The purification method of the present invention is effective when such a metal-containing homogeneous catalyst is dissolved in a solution together with a polymer. In particular, when a polymer having a polar structure or an aromatic ring structure, which is conventionally considered to be more difficult to purify, is dissolved in a solution together with a metal-containing homogeneous catalyst, the metal component has a polar structure or an aromatic ring structure of the polymer. Conventionally, purification has been more difficult because of coordination to the structure. However, according to the method of the present invention, residual metal can be easily reduced.
[0033]
Examples of the organic solvent include, for example, aliphatic hydrocarbons such as pentane, hexane, and heptane; cyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, ethylcyclohexane, diethylcyclohexane, decahydronaphthalene, bicycloheptane, tricyclodecane, Alicyclic hydrocarbons such as hexahydroindenecyclohexane and cyclooctane; aromatic hydrocarbons such as benzene, toluene and xylene; nitrogen-containing hydrocarbons such as nitromethane, nitrobenzene, acetonitrile, dimethylformamide, N-methylpyrrolidone; Ethers such as diethyl ether and tetrahydrofuran; halogen-containing hydrocarbons such as chloroform, dichloromethane, chlorobenzene and dichlorobenzene; Glycol; and the like.
[0034]
In the reaction for preparing these polymers, general reaction conditions are as follows. The polymerization reaction is started by mixing the monomer and the metal-containing homogeneous catalyst in an organic solvent at a polymerization temperature. The amount of the monomer added to the solvent is preferably 1 to 60% by weight, more preferably 2 to 55% by weight. If the concentration of the monomer is too low, the productivity is deteriorated. Conversely, if the concentration is too high, the viscosity of the reaction solution after polymerization becomes too high, which may make it difficult to carry out the hydrogenation reaction thereafter. The amount of the catalyst to be added is usually 0.01 to 50 parts by weight, preferably 0.03 to 30 parts by weight, based on 100 parts by weight of the monomer.
Although the polymerization temperature is not particularly limited, it is generally -30C to 200C, preferably 0C to 180C. The polymerization time is usually from 1 minute to 100 hours.
[0035]
To carry out the hydrogenation reaction, the reaction temperature, hydrogen partial pressure, reaction time, and reaction solution concentration are appropriately set to optimal ranges depending on the type of the target polymer. The method of bringing the polymer solution into contact with the hydrogenation catalyst includes: (1) a method of adding a fixed amount of the hydrogenation catalyst to the polymer solution and stirring and mixing in the presence of hydrogen in the reactor; Any method of passing the polymer solution and hydrogen through a fixed-bed reactor filled with a hydrogenation catalyst can be used. In any case, the hydrogenation catalyst is usually used in an amount of from 0.01 to 50 parts by weight, more preferably from 0.03 to 50 parts by weight, based on 100 parts by weight of the polymer, based on a solution having a polymer concentration of 1 to 30% by weight. Use 30 parts by weight. The reaction temperature during the hydrogenation is preferably 50 to 300 ° C, more preferably 100 to 250 ° C, the hydrogen partial pressure is preferably 0.5 to 10 MPa, more preferably 1 to 8 MPa, and the reaction time is , Preferably 0.5 to 20 hours, more preferably 1 to 10 hours.
[0036]
Examples of monomers that can be used to obtain the above polymer include the following. The monomers can be used alone or in combination of two or more.
[0037]
<Monomer having polar structure or aromatic ring structure>
8-hydroxycarbonyltetracyclo [4.4.0.1^2,5. 1^7,10] Dodeca-3-ene (also referred to as "8-hydroxycarbonyltetracyclododecene"; hereinafter similar in name), norbornene-5,6-dicarboxylic imide, 5-hydroxymethylnorbornene, 8-cyanotetracyclo Norbornene-based monomers having a polar group such as dodecene;
5-phenylbicyclo [2.2.1] hept-2-ene (also referred to as 5-phenylnorbornene; hereafter referred to as this name); tetracyclo [6.6.1]^2,5. 0^1,6. 0^8,13Aromatic groups such as tetradeca-3,8,10,12-tetraene (also referred to as 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene) and 8-phenyltetracyclododecene A norbornene-based monomer having:
Aromatic vinyl monomers such as styrene, α-methylstyrene, 4-methylstyrene, and 4-hydroxystyrene;
[0038]
Monocyclic cycloalkenes having a polar or aromatic ring structure such as methoxycyclopropene, methoxycarbonylcyclobutene, hydroxymethylcyclopentene, cyanocyclopentene, hydroxycarbonylcyclohexene, phenylcyclohexene, chlorocycloheptene, trimethoxysilylcyclooctene;
Monocyclic non-conjugated diene units having a polar structure or an aromatic ring structure such as 6-ethoxy-1,4-cyclohexadiene, 4-hydroxy-1,6-cyclooctadiene and 4-phenyl-1,6-cyclooctadiene Monomer;
Polar structures such as 2-methoxy-1,3-butadiene, 2-hydroxymethyl-1,3-butadiene, 2-hydroxycarbonyl-1,3-pentadiene, 3-phenyl-1,3-hexadiene or aromatic ring structures A chain conjugated diene monomer having;
A monocyclic conjugated diene monomer having a polar structure or an aromatic ring structure such as methoxycyclopentadiene, 6-hydroxymethyl-1,3-cyclohexadiene, 6-ethoxycarbonyl-1,3-cyclooctadiene;
Nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile;
Acrylic esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate; unsaturated fatty acid monomers such as acrylic acid, methacrylic acid, and maleic anhydride;
[0039]
<Monomer having neither polar group nor aromatic group>
Bicyclo [2.2.1] hept-2-ene (common name: norbornene), 5-methyl-bicyclo [2.2.1] hept-2-ene, tricyclo [4.3.0.1^2,5] Deca-3,7-diene (common name: dicyclopentadiene), tetracyclo [7.4.0.1]^10,13. 0^2,7] Trideca-2,4,6-11-tetraene, tetracyclo [4.4.0.1^2,5. 1^7,10A norbornene monomer having neither a polar group nor an aromatic group such as dodeca-3-ene;
Ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4- A linear alkene monomer having neither a polar group nor an aromatic group such as methyl-1-hexene;
A monocyclic alkene having neither a polar group nor an aromatic group such as cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene and vinylcyclohexene;
A chain conjugated diene monomer having neither a polar group nor an aromatic group, such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene;
[0040]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples, and Reference Examples, but the present invention is not limited thereto. Parts and% are based on mass unless otherwise specified. The measuring method was as follows.
(1) Weight average molecular weight (Mw), number average molecular weight (Mn)
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer were determined by gel permeation chromatography (GPC) using cyclohexane as an eluent in terms of Mw and Mn of standard polyisoprene. Was.
(2) Hydrogenation rate (hydrogenation rate)
The hydrogenation rate is¹The ratio (mol) of the hydrogenated carbon-carbon double bond to the carbon-carbon double bond before hydrogenation was determined from the H-NMR spectrum.
[0041]
(3) Metal content
Atomic absorption analysis was performed on the polymer solution using a flameless atomic absorption spectrophotometer, and ruthenium (Ru), which is a metal derived from the catalyst, and sodium (Na), potassium (K), and calcium, which were metals derived from the environment The contents (ppb) of (Ca), iron (Fe), magnesium (Mg), and aluminum (Al) were measured. The detection limit of the used atomic absorption spectrophotometer is 5 ppb for Ru, K, Ca, Fe, Mg, and Al, and 10 ppb for Na.
[0042]
Synthesis Example 1
100 parts of 8-hydroxycarbonyltetracyclododecene, 1.3 parts of 1-hexene, 0.05 parts of 1,3-dimethylimidazolidin-2-ylidene (tricyclohexylphosphine) benzylidene ruthenium dichloride and 400 parts of tetrahydrofuran were substituted with nitrogen. The resulting mixture was charged into a glass pressure-resistant reactor and reacted at 70 ° C. for 2 hours with stirring to obtain a polymer solution A (solid content concentration: about 20%). Mw of the polymer of the polymer solution A was 5,500, and Mn was 3,200.
After confirming by gas chromatography that no unreacted monomer remains in the polymer solution A, a part of the polymer solution A was transferred to an autoclave equipped with a stirrer, and hydrogen was pressured at a temperature of 150 ° C. The polymer was dissolved at 4 MPa and reacted for 5 hours to obtain a polymer solution B (solid content: about 20%) containing a hydrogenated polymer (hydrogenation rate: 100%). Mw of the polymer of the polymer solution B was 7,000, and Mn was 4,070.
Table 1 shows the metal contents of the polymer solutions A and B.
[0043]
Synthesis Example 2
Synthesis Example 1 was performed in the same manner as in Synthesis Example 1 except that a mixture of 8-hydroxycarbonyltetracyclododecene and norbornene in a molar ratio of 80/20 was used instead of 8-hydroxycarbonyltetracyclododecene. A polymer solution C (solid content concentration: about 20%) containing the oxidized polymer (hydrogenation rate: 100%) was obtained. The composition of the polymer obtained by hydrogenation was 80 mol% of 8-hydroxycarbonyltetracyclododecene units and 20 mol% of norbornene units, Mw was 5,300, and Mn was 2,890.
Table 1 shows the metal content of Polymer Solution C.
[0044]
Example 1
A heat-resistant container containing 1 part of activated carbon powder added to 100 parts of polymer solution B was placed in an autoclave, and hydrogen was dissolved at 150 ° C. at a pressure of 4 MPa for 3 hours while stirring. Next, the solution was taken out and filtered through a fluororesin filter having a pore size of 0.2 μm to separate activated carbon to obtain a polymer solution. Filtration was performed without delay. The solution was poured into ethyl alcohol for coagulation, and the resulting crumb was dried. Table 1 shows the metal content of the polymer obtained.
[0045]
Example 2
Example 1 was repeated, except that the polymer solution C was used instead of the polymer solution B. The same test as in Example 1 was performed to obtain a polymer solution. Table 1 shows the results.
[0046]
Example 3
Example 1 was repeated except that the polymer solution A was used in place of the polymer solution B, and the temperature at which hydrogen was dissolved in the polymer solution was 60 ° C. Obtained. Table 1 shows the results of the same test as in Example 1.
[0047]
Comparative Example 1
The procedure was performed in the same manner as in Example 1 except that the mixture was stirred at a temperature of 150 ° C. for 3 hours without using hydrogen. Table 1 shows the results of the same test as in Example 1.
[0048]
Comparative Example 2
A polymer solution was obtained in the same manner as in Example 1 except that nitrogen was used instead of hydrogen. Table 1 shows the results of the same test as in Example 1.
[0049]
Comparative Example 3
A polymer solution was obtained in the same manner as in Example 1 except that the polymer solution A was used instead of the polymer solution B, and nitrogen was used instead of hydrogen. Table 1 shows the results of the same test as in Example 1.
[0050]
[Table 1]

[0051]
As shown in Table 1, in Synthesis Examples 1 and 2, homopolymers and copolymers obtained by ring-opening polymerization and hydrogenation of norbornene monomers having a hydroxycarbonyl group as a polar group with a ruthenium-containing catalyst were used. For the polymers, activated carbon was added to each solution, hydrogen was dissolved at 150 ° C. at 4 MPa for 3 hours, and then the activated carbon was filtered off. In each case, the content of metal ruthenium derived from the catalyst in the polymer was extremely high. The amount of other metals derived from the environment was lower than the detection limit (Examples 1 and 2). Further, for the polymer solution of the homopolymer before hydrogenation obtained in Synthesis Example 1, the metal content was reduced by lowering the temperature at which hydrogen was dissolved from 150 ° C. to 60 ° C. without hydrogenating the polymer. It could be extremely reduced (Example 3).
On the other hand, even if activated carbon was added to the solvent solution of the homopolymer and stirred at a temperature of 150 ° C. for 3 hours, a reduction in metal was observed in the polymer obtained by filtration without dissolving hydrogen in the solution. No (Comparative Example 1).
In addition, the same procedure as in Example 1 was carried out except that nitrogen was used instead of hydrogen, and the metal content of each polymer was large (Comparative Examples 2 and 3).
[0052]
【The invention's effect】
According to the purification method of the present invention, not only the metal derived from the catalyst remaining in the polymer but also the metal mixed from the environment such as a metal reactor and other reaction materials can be significantly reduced.
Since the polymer thus purified by the purification method of the present invention contains almost no metal, electronic components such as an electric insulating film for manufacturing a semiconductor, a cover film for a display element, and a sealing film; It can be suitably used for optical products and the like.

Claims (6)

A method for purifying a polymer, comprising bringing a polymer solution containing a polymer, a metal component, and an organic solvent into contact with an adsorbent, wherein the temperature of the polymer solution is 40 to 200 ° C, and the temperature of the polymer solution is A method for purifying a polymer wherein the partial pressure of dissolved hydrogen is 0.1 to 10 MPa. The method for purifying a polymer according to claim 1, wherein the polymer has a polar structure or an aromatic ring structure. The method for purifying a polymer according to claim 1, wherein at least one of the metal components is a metal-containing homogeneous catalyst used for obtaining the polymer. The method for purifying a polymer according to claim 3, wherein the metal-containing homogeneous catalyst is a catalyst containing a platinum group atom. The polymer solution is prepared by heating a solution containing a polymer, a metal component and an organic solvent to 40 to 200 ° C in an environment having a hydrogen partial pressure of 0.1 to 10 MPa. A method for purifying a polymer. A polymer obtained by the method for purifying a polymer according to any one of claims 1 to 5, wherein the metal content derived from the catalyst used to obtain the polymer is 50 ppb or less.