WO2002002651A1 - Process for continuously producing hydrogenated styrene block copolymer - Google Patents

Abstract

A process for economically and continuously producing a hydrogenated styrene block copolymer having high heat resistance and high transparency; and a hydrogenated styrene block copolymer suitable for use as an optical molding material. The continuous process for producing a hydrogenated styrene block copolymer comprises the step of stepwise polymerizing a styrene monomer solution, a solution of an anionic polymerization initiator, and a conjugated diene with a piston flow type polymerizer and the step of hydrogenating the copolymer obtained.

Description

 Description Continuous production method of hydrogenated styrene-based block copolymer

 The present invention relates to a method for continuously producing a hydrogenated styrene block copolymer and a hydrogenated styrene block copolymer. More specifically, the present invention relates to a method for economically producing a hydrogenated styrene-based block copolymer having high heat resistance and a hydrogenated styrene-based block copolymer suitable for an optical molding material.

 The present invention particularly relates to a method for continuous production of a hydrogenated styrene-based block copolymer with increased transparency and a hydrogenated styrene-based block copolymer with enhanced transparency: Method for economically producing hydrogenated styrenic propylene copolymers with enhanced transparency and heat-resistant hydrogenated polymers with enhanced transparency

The present invention relates to a system block copolymer.

Plastics used for optical materials such as optical disk substrates and optical lenses include, in addition to transparency, various properties such as optical isotropy (low birefringence), dimensional stability, light resistance, weather resistance, heat resistance, etc. Characteristics are required. Conventionally, polycarbonate or polymethyl methacrylate has been mainly used for these optical materials. However, if polycarbonate has a high intrinsic birefringence and optical anisotropy is likely to occur in molded products, and polymethyl methacrylate has a very high water absorption, it has poor dimensional stability. Had been a problem. Currently, poly-carbonate is used exclusively for optical disc substrates. However, in recent years, with the increase in the capacity of magneto-optical recording disks (Μ Ο), the development of digital video disks (DVD), and the increase in recording density represented by the development of blue lasers, the There is a growing concern about the size of the refraction and the warping of the disk due to moisture absorption. Under these circumstances, development of a polyolefin-based resin called amorphous polyolefin as an alternative material to polycarbonate has been active in recent years. As an example of these, Hydrogenated polystyrene in which an aromatic group of polystyrene is hydrogenated to have a polyvinylcyclohexane structure has been proposed (Japanese Patent Publication No. 7-114030). Such a resin has a great advantage that it can be produced at a lower cost than other amorphous polyolefins, but has a drawback that it is mechanically brittle. In order to improve these drawbacks, block copolymerization of styrene with conjugated isomers such as isoprene and butadiene is used to obtain hydrides of styrene-conjugated genlock copolymers with rubber components and optical disk substrates. Examples have been reported for use in optical applications (Japanese Patent No. 2730503, Japanese Patent No. 272542). Such a hydrogenated styrene-conjugated gemrock copolymer has an effect of improving the mechanical brittleness of a hydrogenated styrene polymer by introducing a small amount of a rubber component into a styrene polymer as a precursor. . However, when the amount of the rubber component increases, the transparency tends to decrease due to excessive phase separation due to aggregation of the hydrogenated rubber component (soft component). Disclosure of the invention

 An object of the present invention is to provide an economical continuous production method for obtaining a hydrogenated polystyrene block copolymer without lowering heat resistance and transparency. In other words, (1) to obtain a hydrogenated styrene-based block copolymer structure having a narrow molecular weight distribution while efficiently shielding the flexible phase by the rigid phase, and (2) hydrogen-free substantially containing a conjugated gen homopolymer. It is an object of the present invention to provide a continuous production method for efficiently obtaining a styrene-based block copolymer.

 Generally, anionic polymerization of styrene-based monomers is based on the reaction of generating a growing species by the reaction of an anionic polymerization initiator with the monomer (initiation reaction) and the subsequent repetitive reaction of the growing species with the monomer (growth reaction). Become.

In a batch reaction, if the initiating reaction is much faster than the growth reaction, the initiating reaction is completed at an earlier point in time, and then the growing reaction occurs. Therefore, a polymer having a uniform molecular weight can be obtained. In addition, the growth terminal contains anion, and when a co-gen is further added to this reaction system, the anion that gives a block copolymer by addition polymerization of the conjugated gem is called a living anion. A styrene-based polymer containing living anion is called a living styrene-based polymer. On the other hand, if the initiation reaction is not sufficiently fast compared to the growth reaction, the initiation reaction and the growth reaction occur competitively. For this reason, the molecular weight of the obtained living styrene-based polymer is not uniform, and a wide distribution occurs. Therefore, a styrene block copolymer in which the chain lengths of the styrene block and the conjugated block are not uniform even when the conjugated diene is added. Further, by reacting the living copolymer with a radializing agent to obtain a styrene-based radial block copolymer having a radial structure, not only the chain length of the entire branch but also the block of the styrene-based component constituting the branch is obtained. And the conjugated gen component will also be uneven. Even if such a styrenic block copolymer is hydrogenated, it is difficult to obtain a high shielding effect by a rigid linear chain. On the other hand, when the living styrene-based polymer is obtained, if the initiation reaction is not completed at the stage when the styrene-based monomer dies, homopolymerization of the conjugated gen added continuously occurs. Therefore, after the addition of hydrogen, the hydrogenated conjugated homopolymer becomes present at least in the polymer, resulting in a loss of transparency.

 Although the above is the batch reaction, the degree of irregularity of the polymer structure is further increased in a reaction using a generally used continuous apparatus comprising a complete mixing tank. In such a continuous apparatus, a fixed ratio of a styrene-based monomer and an initiator solution are continuously introduced into a polymerization apparatus at a constant rate. At the same time, the reaction solution is withdrawn from the vessel at the same rate as the introduction rate, and sent to the next conjugated gen polymerization apparatus. In such a reaction system, a new initiator is continuously introduced together with the styrene-based monomer into the reaction solution in which the growth reaction has already progressed. Therefore, the molecular weight of the living styrenic polymer becomes much more irregular than that of the batch reaction. As is clear from this, it is extremely difficult to obtain a block copolymer having the same molecular weight and the same chain length of each component when a complete mixing tank is used.

 Based on such an idea, the present inventors have paid attention to a piston-type one-type polymerization apparatus comprising one or more static mixers, and have arrived at the present invention as a result of intensive studies.

 That is, the first aspect of the present invention relates to a method for producing a hydrogenated styrene block copolymer,

 The following steps (1) to (4):

(1) A styrene monomer solution and an anion polymerization initiator solution are A step of continuously introducing the anion polymerization initiator into the piston flow type polymerization apparatus (polymerization apparatus a) composed of the above-described stick mixer until the anion polymerization initiator is substantially consumed (polymerization step A). ),

 (2) A piston composed of one or more static mixers in a predetermined ratio of the polymer solution obtained in the polymerization step A, a conjugated gen or a solution of the conjugated gen, and a styrene-based monomer solution as required. A step of continuously introducing into a flow type polymerization apparatus (polymerization apparatus b) to perform block copolymerization (polymerization step B);

 (3) If necessary, the block copolymer solution obtained in the polymerization step B and the styrene-based monomer solution are added at a predetermined ratio to a piston flow type polymerization apparatus comprising at least one static mixer (polymerization apparatus). A step of continuously introducing into the apparatus c) to perform block copolymerization (polymerization step C), and

 (4) The block copolymer solution obtained in the polymerization step B or the polymerization step C is continuously introduced into a hydrogenation apparatus to form an aromatic group and a c = c double bond in the copolymer. Hydrogenation step in the presence of a hydrogenation catalyst (hydrogenation step),

Is a method for continuously producing a hydrogenated styrene block copolymer.

 Further, according to a second aspect of the present invention, the process for producing a hydrogenated styrene-based block copolymer includes the following steps (1 ′) to (4 ′):

 (1 ') A styrene monomer solution and an anion polymerization initiator solution are continuously introduced at a predetermined ratio into a piston flow type polymerization apparatus (polymerization apparatus a) comprising one or more stick mixers. And polymerizing until the anion polymerization initiator is substantially consumed (polymerization step A).

(2 ') A biston flow type polymerization apparatus (polymerization apparatus b) comprising one or more sticky mixers at a predetermined ratio of the polymer solution obtained in the polymerization step A and the conjugated gen or a solution of the conjugated gen. ⁵ ) a step of continuously introducing into the block copolymerization (polymerization step B ′),

(3,) The block copolymer solution obtained in the polymerization step B and the radializing agent solution having three or more functional groups are mixed at a predetermined ratio with a piston flow comprising one or more sticky mixers. To perform a radialization reaction (radialization step) by introducing into a mold type reaction device (radialization device), and (4,) The radial block copolymer solution obtained in the radialization step is continuously introduced into a hydrogenation apparatus, and the aromatic group and C 2 C double bond contained in the copolymer are hydrogenated. Hydrogenation in the presence of an added catalyst (hydrogenation step),

Is a method for continuously producing a hydrogenated styrene-based block copolymer comprising:

 Furthermore, the present invention provides a hydrogenated styrene-based block copolymer obtained by the above method, an optical molding material comprising the hydrogenated styrene-based block copolymer obtained by the above method, and a total light transmittance of 88%. As described above, the optical molding material having a haze value of 5% or less and the optical molding material having a heat deformation temperature of 100 ° C. or more. BEST MODE FOR CARRYING OUT THE INVENTION

 The static mixer used in the present invention comprises a mixing element provided in a pipe. When the reaction solution is introduced into the passage, the reaction solution proceeds from upstream to downstream. In the meantime, the reaction proceeds. As is evident from the principle, if the equipment and conditions are properly selected, the upstream reaction solution and the downstream reaction solution will not mix. That is, it shows the piston flow property. Therefore, the mixing and reaction between the newly introduced monomer and initiator solution and the reaction solution already in the reaction tank do not occur, as seen in the reaction in the complete mixing tank type continuous apparatus, and the molecular weight does not increase. · A block copolymer having a uniform composition can be obtained. At this time, in the styrene polymerization step (polymerization step A), by controlling the initiator to be consumed before the styrene monomer is depleted, the conjugated gen polymerization step (polymerization step B or B ′) In this case, undesired byproducts of the conjugated homopolymer are suppressed. On the other hand, in the styrene monomer polymerization process using a complete mixing tank type continuous apparatus, the initiator is instantaneously introduced into the reaction solution together with the styrene monomer, so the initiation reaction is instantaneous. Unless this occurs, some unreacted initiator will always be present in the reaction. Even if the initiation reaction occurs instantaneously, a styrene-based living polymer having an extremely short molecular weight will always be present in the reaction system. For this reason, it is inevitable that by-products of unsuitable conjugated homopolymers and styrene-based copolymers that are extremely short in the conjugated polymerization step are undesirable.

(Get up.

Hereinafter, each step of the present invention will be described. <Polymerization step A>

 In the polymerization step A, a styrene monomer solution and an anion polymerization initiator solution are continuously supplied at a predetermined ratio to a piston flow type polymerization apparatus (polymerization apparatus a) comprising one or more static mixers. And polymerize until the anion polymerization initiator is substantially consumed. In the polymerization step A, the term "substantially exhausting the anion polymerization initiator" means that after the polymerization step A, the added anion polymerization initiator is consumed in an amount of 99% by weight or more.

 Examples of the styrene monomer used in the present invention include styrene, monomethyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-tert-butyl styrene, and vinyl naphthylene. Of these, styrene is most preferably used in view of availability and polymer properties. These monomers can be used alone or in combination.

 The anion polymerization initiator used in the present invention is not particularly limited, but generally an organic lithium compound is used. Specific examples include ethyl lithium, n-butyl pill lithium, isopropyl lithium, n-butyl lithium, isobutyl lithium, sec-butyl lithium, and tert-butyl lithium. Of these, η-butyllithium or sec_butyllithium is preferably used because of its easy availability, ability to initiate a polymerization reaction, or ease of handling. In general, the initiation reaction with sec-butyllithium is very fast, whereas the initiation reaction with n-butyllithium is slow in the hydrocarbon solvents described below. Therefore, sec-butyllithium is more preferable for obtaining a living styrene polymer having a uniform molecular weight in a hydrocarbon solvent.

As the polymer solvent used in the present invention, a hydrocarbon solvent is generally used. Specifically, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and decane; cyclopentane, methylcyclopentane, and cyclohexane And group V hydrocarbons such as methylcyclohexane, cyclooctane and decalin; and aromatic hydrocarbons such as benzene, toluene, xylene and tetralin. Among such hydrocarbon solvents, cyclohexane and methylcyclohexane are preferably used in view of solubility, reactivity, economy and the subsequent hydrogenation step. In addition to the hydrocarbon solvent, a polar solvent may be used for the purpose of controlling the microstructure of the conjugated gen moiety in the polymerization reaction control step (polymerization step B). Generally, the use of a polar solvent significantly accelerates the initiation reaction. Therefore, when living styrene having a uniform molecular weight cannot be obtained in a hydrocarbon solvent, a polar solvent may be used in combination. Examples of such polar solvents include linear, branched, and cyclic ethers such as tetrahydrofuran, dioxane, diethyleneglycol-dimethylether, getylether, methyl-tert-butylether; and triethylamine, tetraethylenediamine, and the like. Amines; phosphines; These hydrocarbon solvents and polar solvents may be used alone or as a mixture of two or more. In addition, the initiator used for anion polymerization and the growth terminal during the polymerization process are easily decomposed and deactivated by impurities including ice. In that sense, the solvent used is preferably highly purified. The concentration of the styrene monomer depends on the constitution of the styrene copolymer which is a precursor of the obtained hydrogenated styrene copolymer, but is generally 3 to 40% by weight, preferably 5 to 30% by weight. % By weight. Below this, not only the productivity is lowered, but also a trace amount of water contained in the solvent is not preferable because it deactivates the polymerization active terminal. On the other hand, if it is higher, the heat of the polymerization reaction becomes too large, and the viscosity of the solution becomes too high as the polymerization proceeds.

 On the other hand, the amount of the anion polymerization initiator used controls the molecular weight of the styrene-based copolymer.

 In general, increasing the amount used decreases the molecular weight, and decreasing it increases the molecular weight. If the initiation reaction is much faster than the growth rate, the degree of polymerization is the value obtained by dividing the number of moles of the monomer used by the number of moles of the anion polymerization initiator. In the present invention, generally, the range of 0.01 to 5 mol%, preferably 0.02 to 2 mol%, is used based on the total number of moles of the styrene monomer and the conjugated diene.

In general, a method of mixing the styrene-based monomer solution and the anion polymer solution used in the present invention immediately before entering a static mixer is employed. It is not preferable to introduce the mixed solution into a static mixer after mixing the two in advance, since polymerization starts during storage of the mixed solution. The introduction rate of the polymer solution containing the styrene monomer solution and the anion polymerization initiator solution depends on the mixing characteristics, heat generation rate, Is selected in consideration of the equipment constant heat removal efficiency of the device, generally the scan evening Tikkumi Kisa mass flow rate per average effective area one is ^{1~1 o 3 kg / m 2 ·} s, preferably 1 0 A range of ~ 50 O kg / m ² · s is used. Exceeding this is not preferable because the pressure loss becomes too large and the running cost increases. If the temperature is lower than this, heat generation becomes excessive and heat removal cannot keep up, which is not preferable.

 The polymerization temperature used in the present invention is usually in the range of −20 to 120 ° C., and preferably in the range of 10 to 100 ° C. Exceeding this range is not preferred because not only does the reaction rate become too high to control the temperature, but also causes undesirable side reactions. On the other hand, if it is less than that, the reaction becomes too slow, which leads to a decrease in productivity. In order to prevent deactivation of the polymerization catalyst and active terminals (living anion terminals) during polymerization, it is preferable to carry out the reaction in an atmosphere of an inert gas such as nitrogen or argon.

 <Polymerization step B>

 In the polymerization step B, the polymer solution obtained in the polymerization step A and the conjugated gen or a solution of the conjugated gen and, if necessary, a solution containing a styrene-based monomer are added at a predetermined ratio to one or more. It is continuously introduced into a piston flow type polymerization device (polymerization device b) consisting of a static mixer to perform polymerization.

Examples of the conjugated gen used in the present invention include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentene, 1,3-hexadiene, and the like. Of these, 1,3-butadiene and isoprene are preferred from the viewpoints of polymerization activity, economy, and physical properties of the obtained hydrogenated styrene-based block copolymer. These may be used alone or in combination of two or more. By introducing these copolymer components, the mechanical properties can be significantly improved without impairing the transparency of the intended hydrogenated styrene-based block copolymer. The introduction rate is 1 to 30% by weight, preferably 2 to 20% by weight, based on the total amount of all the monomers to be introduced, that is, the total of all the styrene-based monomers to be introduced and the conjugated diene. More preferably, 3 to 15% by weight is used. Exceeding this range is preferable from the viewpoint of toughness and impact resistance, but is not preferable because rigidity, heat resistance, and transparency decrease. Conversely, if it is less than this, the toughness becomes insufficient and the material becomes brittle, which is not preferable. In addition, the same styrene monomer as used in the polymerization step A can be used as the styrene monomer added as needed. The purpose of adding the styrene monomer at the same time is to form a gradient block containing the styrene monomer component in the conjugated gen component. In general, conjugated gens are more easily incorporated than styrenic monomers. Therefore, in the initial stage of the polymerization step B, a large amount of the conjugated gen component is introduced, and as the conjugated gen in the polymerization system gradually decreases, the styrene-based monomer component in the copolymer relatively increases. come. Then, after the conjugated component is depleted, the styrene-based monomer becomes a single chain. Therefore, considering step A together, a gradient block copolymer consisting of a styrene-based conjugated styrene-based gradient chain-a styrene-based gradient chain is obtained.

 The conjugated gen may be introduced as a solution or may be introduced as it is. In general, a method is adopted in which a liquid is introduced as a solution and a gas is injected without dilution.

 As a solvent when introduced as a solution, those described in the polymerization step A may be used. However, the microstructure of the conjugated gen chain changes depending on the solvent used. In the case of bushgene, for example, when the above-mentioned hydrocarbon solvent is used, it is mainly a 1,4-bond chain. On the other hand, when a polar solvent such as ethers is used, a mixed chain of 1,4-single bond and 1,2-bonded chain is obtained. The ratio also depends on the type of solvent.

 On the other hand, in the case of gas, it is preferable to introduce it without dilution. Injection should be performed at a constant pressure and a constant flow rate. These are easily achieved by installing and controlling a flow meter. As in the case of the solution, the solution is introduced at a rate suitable for the desired introduction rate. The pressure is set at 0.1 to l MPaG. The polymerization temperature and atmosphere may be the same as those in the polymerization step A. '

 <Polymerization step B '>

 In the polymerization step B ′, the polymerization solution obtained in the polymerization step A and the conjugated gen or the conjugated gen solution are added at a predetermined ratio to a piston flow type polymerization apparatus (a polymerization apparatus) comprising one or more stick mixers. b,) Continuously introduced into and polymerized.

The polymerization steps B and B are the same when the styrenic monomer is not used in the polymerization step B. Hit. The conjugated gen to be used, the introduction rate, the reaction conditions and the atmosphere are as described in the polymerization step B. Note that the copolymer obtained in this step is a block copolymer composed of a styrene chain and a conjugated gen chain. Therefore, it is not possible to obtain a block arrangement form in which the flexible component, which the present inventors intend, is sandwiched between the rigid components, by this alone. Only after a subsequent radialization step can such a block arrangement be obtained.

 <Polymerization step C>

 In the polymerization step C, the polymer solution obtained in the polymerization step B and the styrene-based monomer solution are mixed at a predetermined ratio in a piston flow type polymerization apparatus (polymerization apparatus c) comprising one or more stick mixers. And continuously polymerized.

 The styrene monomer solution used in the present invention is as described in the polymerization step A. The purpose of the polymerization step C is to obtain a block copolymer composed of a styrene chain, a conjugated gen chain and a styrene chain through the polymerization step A, the polymerization step B, and the polymerization step C. Therefore, the solution concentration and the introduction speed may be set in consideration of the styrene chain length. The polymerization temperature and atmosphere can be the same as those in the polymerization step A.

 <Radialization process>

 In the radialization step, the copolymer solution obtained in the polymerization step B and the trifunctional or higher radiating agent solution are mixed at a predetermined ratio with one or more stick mixers. To perform a radialization reaction.

In this step, a block copolymer composed of a styrene-based chain and a conjugated gen chain is bonded at the terminal of the conjugated gen chain with a trifunctional or higher polyfunctional radializing agent. Is the limit of the number of functional groups. Such a polyfunctional radializing agent is not particularly limited as long as it reacts with the active terminal of the block copolymer to generate a covalent bond. Commonly used are chlorosilanes such as tetrachlorosilane, trichloro (methyl) silane, bis (trichlorosilyl) methane, bis (trichlorosilyl) ethane, and bis (trichlorosilyl) hexane; dimethyl terephthalate, isofuryl Diesters such as dimethyl dimethyl oxalate, dimethyl oxalate and methyl malonate; trimethyl trimellitate, tetrame pyromellitic acid Polyfunctional esters such as chill esters are used. In the case of an ester group,

One acts as a bifunctional. Further, in the present invention, more preferred radializing agents include alkoxysilane compounds. The alkoxysilane compound specifically refers to a compound represented by the following general formulas (I) to (IV).

S i (ORJ _m R ₂₄ _ _m

S i ₂ (0) _n R ₂₃ - _n · · · (II)

R ₃ [S i (OR _n R ₂₃ _J ₂

0 [Si (OR _n R ₂₃ -1 J ₂ ··· (IV) (In the formulas (I) to (IV), and R ₂ are the same or different, an alkyl group having 1 to 8 carbon atoms or 6 to 18 carbon atoms.) R ₃ is an alkylene group having 1 to 10 carbon atoms, m is 3 or 4, and n is 2 or 3.) The alkoxy represented by the above (I) to (IV) in silane compounds, R have R _2, a methyl group, Echiru group, a propyl group, a § Li Ichiru group can preferably be exemplified. R ₃ such as an alkyl group or phenyl group such as a butyl group, Preferred are alkylene groups such as methylene group, ethylene group, 1,6-hexylene group, etc. Specific compounds include tetramethoxysilane, tetraethoxysilane, tetrafluoroethoxysilane, trimethoxy (methyl) silane, and bis (trimethoxysilane). Lil) Ethan, bis ( Trimethoxysilyl) hexane, bis (trimethoxysilyl) ether and the like.

 Alkoxysilanes only produce alcohol by a radialization reaction.Unlike the case where chlorosilanes are used in the subsequent hydrogenation reaction, they are suitably used without concern about corrosion of high-pressure hydrogenation equipment by acids. .

 As the solvent used for diluting the radializing agent, the solvent for diluting styrene described in the section of the polymerization step A is used. The concentration may be used in an amount equivalent to the active terminal of the living block copolymer solution obtained in the polymerization step B ′. Therefore, it is necessary to consider the number of functional groups in the radializing agent.

The radiating reaction depends on the kind of the radiating agent used, but is usually in the range of 120 to 150 ° C _S, preferably 10 to 120 ° C. Below it is radial The polymerization reaction is difficult to proceed, and if it exceeds this, the living anion terminal of the active copolymer is deactivated, which is not preferable.

 <Hydrogenation process>

 In the hydrogenation step, the styrene block copolymer solution obtained in the polymerization step B, the polymerization step C or the radialization step is continuously introduced into a hydrogenation apparatus, and the aromatic group in the copolymer is added. And the C = C double bond is hydrogenated in the presence of a hydrogenation catalyst.

 The hydrogenation catalyst used in the present invention is not particularly limited as long as it can efficiently hydrogenate an aromatic group and a C = C double bond. Specifically, noble metals such as nickel, palladium, platinum, cobalt, ruthenium, and rhodium or compounds such as oxides, salts, and complexes thereof, or compounds such as carbon, alumina, silica, silica alumina, diatomaceous earth, etc. A solid catalyst supported on a carrier may be used. Among them, those in which nickel, palladium, rhodium, and platinum are supported on alumina, silica, silica-alumina, and diatomaceous earth have high activity and are preferably used. Such a hydrogenation catalyst is used in an amount of 0.5 to 40% by weight, preferably 1 to 30% by weight based on the block copolymer, depending on its catalytic activity.

The hydrogenation reaction conditions are usually a hydrogen pressure of 3 to 25 MPa aG, preferably 5 to 15 MPa aG, a reaction temperature of 70 to 250 ° C, preferably 100 to 200 ° C. If the _c- hydrogen pressure performed in the above range is too low, the progress of the reaction is slow, and if it is too high, the load on the apparatus becomes too high, which is not preferable. On the other hand, if the reaction temperature is too low, the progress of the reaction will be slow, and if it is too high, the molecular weight will decrease due to cleavage of the molecular chain. In order to prevent a decrease in molecular weight and promote the reaction smoothly, it is necessary to carry out the hydrogenation reaction at an appropriate temperature and hydrogen pressure appropriately determined by the type and concentration of the catalyst used, the solution concentration of the copolymer, the molecular weight, etc. I like it.

 The hydrogenation apparatus used in the hydrogenation reaction is not particularly limited, and a normal high-pressure reaction vessel can be used.

Purification of the hydrogenated styrene-based block copolymer thus obtained is not particularly limited, and a usual method can be employed. Usually, in the hydrogenation reaction step, the catalyst is obtained from the obtained hydrogenated styrene-based block copolymer solution by centrifugation or filtration. Can be obtained. In the present material suitable for use in optical materials, it is necessary to minimize the amount of residual catalyst in the copolymer. Such residual catalyst metal is at most 10 ppm, preferably at most 5 ppm, more preferably at most 2 ppm.

 <Explanation of piston flow type polymerization equipment and operation>

 The piston flow type polymerization apparatus used in the present invention is mainly composed of one or more stick mixers. In addition, a preliminary reaction between a polymerization initiator and a monomer, or a living (co) polymer and a monomer or a radializing agent. Ancillary equipment for temperature control such as a mixing device and a jacket are added. The STICK mixer consists of mixing elements installed in the pipe. When a fluid passes through its mixing element, the actions of fluid division, direction change, and re-merge are basically repeated alternately from 0 to 180 degrees and from 90 to 270 degrees, and the fluid is mixed. Will be done. By introducing the reaction solution into the passage, the reaction solution proceeds sequentially from upstream to downstream. During this time, the reaction solution is mixed and the reaction proceeds. As is evident from the structure of the equipment, the upstream reaction solution and the downstream reaction solution do not mix if the equipment and conditions are properly selected. That is, it shows the piston flow.

As the static mixer used in the present invention, at least one selected from a Kenics type static mixer, a Sulzer type static mixer, a Komax type static mixer, a Ross-ISG type mixer, and a Lightnin type mixer is used. Can be The mixing characteristics and heat removal capacity are determined by the shape of the mixing element, the average effective area, and the flow velocity in the pipe. The average effective area is the volume of the tube divided by the length. In general, the average effective area 1 0 _ ⁴ ~lm ^2, and preferably those of ^{1 0 _ 3 ~1 0- 1 m} 2 used. If it exceeds this, not only poor mixing in the tube will occur and good biston flow properties will not be obtained, but also the relative area of the wall with respect to the volume of the reaction space (bent passage) will decrease, and the heat removal efficiency will decrease, which is not desirable . On the other hand, if it is less than this, not only productivity is lowered but also pressure loss becomes too large, which is not preferable. The length may be appropriately set according to the reaction speed. If the length is too short, it is not preferable because a reaction solution comes out unreacted. Generally, 0.5 to 5 m are connected in series to obtain a desired length according to the reaction rate. In the present invention, the piston flow property is such that the initiation reaction is significantly faster than the growth rate. Polymerization is performed using the reaction system, and the molecular weight distribution Mw / Mn of the obtained (co) polymer can be easily evaluated by determining the molecular weight distribution Mw / Mn. If the distribution is 1.0, it indicates complete piston flow, and if it exceeds this value, the piston flow will decrease as the opening from 1.0 increases. Therefore, the piston flow characteristics can be easily compared according to the size. In addition, the evaluation of the piston flow property can be compared with a reaction apparatus of a force skade type using a complete mixing tank by the method described later.

 In many cases, the stick mixer used in the present invention controls the temperature using an external jacket.

 The number of the stick mixer in the piston flow type polymerization apparatus in the present invention is not necessarily required to be one. A plurality of tubes may be bundled and used according to the processing amount (production amount). When the processing amount is large, it is preferable to bundle multiple thin static mixers instead of using one thick static mixer because the heat removal efficiency becomes higher. Particularly in the case of a continuous reaction composed of a plurality of unit reactions as in the present invention, good results can be obtained by setting the number of stick mixers used in each unit reaction so that the mass balance of each reaction is matched.

 In the present invention, for example, in the case of the polymerization step A, if the styrene-based monomer solution and the anion polymerization initiator solution are directly introduced into the static mixer without pre-mixing, non-uniformity may occur depending on conditions. Polymerization may occur as it is. In such a case, premixing is preferably performed. It is preferable that such pre-mixing be carried out by cooling as short as possible. Otherwise, the polymerization reaction proceeds in the premixing stage, and the characteristics of the polymerization reaction using the static mixer are lost. Preferably, an efficient mixing device such as a homogenizer is installed near the entrance of the static mixer. In addition, a method of attaching one cooled standby static mixer immediately before the static mixer is also effectively used. Due to the low temperature, mixing occurs in the preliminary stick mixer, but the reaction is suppressed, so that the polymerization does not occur heterogeneously.

The rate of introduction of the reaction solution used in the present invention, when viewed in mass flow per average effective ^{area, 1~1 0 3 kg / m 2} · s, 2 · preferably 1 0~5 0 O k gZ m A range of s is used. Beyond that, pressure loss increases and runnin W costly and unfavorable. On the other hand, if it is less than this, not only productivity is lowered but also heat removal ability is lowered, which is not preferable.

 FIG. 1 shows a flow sheet according to a preferred embodiment of the present invention, taking a hydrogenated styrene-isoprene-styrene block copolymer as an example.

5 The styrene monomer solution and the initiator solution are introduced into the premixing tank through the introduction pipes 1 and 2 at a fixed ratio by the metering pump. The mixed solution is uniformly mixed in a very short time in the premixing tank, and then introduced into the piston flow type polymerization apparatus a. As the reaction of the mixed solution proceeds, heat of reaction is generated, but the internal temperature is controlled to a constant temperature by the jacket.

Next, the isoprene solution is introduced into the premixing tank through the conduit 4. The mixed solution of the styrene polymer solution and the isoprene solution reacted in the piston flow type polymerization apparatus a is introduced into the piston flow type polymerization apparatus b after being uniformly mixed in a very short time. Similarly, the internal temperature is controlled at a constant temperature.

 A styrene solution is introduced through conduit 7 and the reaction is carried out in the same manner to produce a block copolymer.

 This block copolymer is sent to a hydrogenation reactor through a conduit 8 and hydrogenated. <Explanation of evaluation of piston flow uniformity>

 The piston flowability was determined by comparing the experimental results of the residence time and the conversion with the theoretical curve of the residence time and the conversion obtained from a cascade type continuous polymerization apparatus consisting of N complete mixing tanks. Can be Taking the polymerization of styrene with sec-butyllithium in cyclohexane at 45 ° C as an example, the polymerization rate equation and the reaction rate constant for styrene are represented by the following equations.

— D [S] / dt = k [se c-BuL i] ^1/2 [S]

 [S]: Styrene concentration

 [sec-BuLi]: initial concentration of sec-butyllithium k: reaction rate constant

Here, the rate constant is k = 0.041M " ^1/2 · min- ¹ .

On the other hand, the relationship between the residence time and the conversion when N cascade reactors are used is expressed by the following equation. 1-X = 1 / (1 + K r) ^N

 N: Number of reaction tanks

K: reaction rate constant including initiator concentration (= k [sΘc-BuLi] ^1/2 ) r: residence time

 X: Conversion rate

 The relation between X and X obtained by this equation is plotted using N as a parameter, and the residence time obtained by the experiment and the data of conversion can be compared. If the corresponding N is large, the biston flow uniformity is high.

 <Description of hydrogenated styrene-based block copolymer>

 The structure of the hydrogenated styrene-based block copolymer thus obtained can be confirmed by a method known per se. The ratio of the hydrogenated styrene block component to the hydrogenated conjugated gen block component and the microstructure of the hydrogenated conjugated gen block can be determined by the NMR spectrum of the hydrogenated styrene block copolymer or its precursor, the styrene block copolymer. Can be quantified. The hydrogenation rate can also be quantified by the NMR spectrum of the hydrogenated styrene-based block copolymer. The molecular weight can be determined by gel permeation chromatography (GPC), and measurement of reduced viscosity is also preferably used as one measure of molecular weight. The degree of radialization can be determined by the GPC method. In addition, the undesirable conjugated diene polymer mixed in the polymerization step may be obtained by isolating the styrene-based block copolymer after polymerization, preparing a film sample, and observing the film sample with a transmission electron microscope. At that time, it is preferable to stain with osmic acid or the like according to a conventional method. If the conjugated-gen polymer is not mixed, a sea-island structure in which islands of tens of microns of conjugated-gen components are uniformly dispersed in the sea of styrene-based components is observed. When conjugated gen polymers are incorporated, islands of several hundred microns are observed in some places. In that case, the sea-island structure derived from the island structure will be generated even after hydrogenation, causing a loss of transparency.

The hydrogenation rate of the hydrogenated styrene-based block copolymer used in the present invention is preferably 95% or more, more preferably 97% or more, and preferably 99% or more. If it is less than this, the transmittance of the molded product is not sufficient, which is not preferable. The hydrogenated styrene block copolymer used in the present invention is measured by the GPC method. The determined weight average molecular weight (Mw) in terms of polystyrene is 100,000 to 400,000, preferably 15,500 to 300,000. Exceeding this is not preferred because the resin viscosity is too high and the moldability decreases. On the other hand, if it is less than that, the mechanical strength of the molded product is undesirably reduced. The uniformity of the molecular weight distribution is represented by the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn). The molecular weight distribution (Mw / Mn) is preferably in the range from 1.0 to 1.3, more preferably in the range from 1.0 to 1.2. Beyond that, the effect of using a piston flow type reactor is not expected. However, in the case of a radially hydrogenated styrene-based block copolymer, the molecular weight dispersion of the branch portion is used.

 In the present invention, the content of the hydrogenated styrenic polymer block contained in the copolymer is preferably 70 to 99% by weight, and further, it is substantially free of hydrogenated gen-based polymer. Is preferred. In addition, the term “substantially not containing a hydrogenated gen-based polymer” means that a sea-island structure derived from an island structure of several hundred microns is hardly observed.

 In the present invention, in order to improve the thermal stability of the hydrogenated styrene-based block copolymer, a hindered-dophenol-based or ilgafos-based compound such as ilganox 101, 106 (manufactured by Chipagaigi Co., Ltd.) is used. It is preferable to add a stabilizer represented by a phosphite type such as 8 (manufactured by Ciba Geigy). In addition, stabilizers containing an acrylic group, such as Sumilizer-1 G S ゃ Silizer-1 GM, are also preferably used. If necessary, a releasing agent such as a long-chain aliphatic alcohol and a long-chain aliphatic ester, and other additives such as an active agent, a plasticizer, an ultraviolet absorber, and an antistatic agent can be added.

The hydrogenated styrene block copolymer thus obtained can be formed into a desired shape by a usual method such as an injection molding method, a compression molding method, or an extrusion molding method. Also, it can be formed into a film shape by melt film formation or cast film formation. Taking the injection molding method as an example, the resin temperature is in the range of 200 to 400 ° C., preferably 250 to 350 ° C. If it exceeds this, thermal decomposition of the molding resin occurs, and if it is less than that, the fluidity of the resin is too low, which is not preferable. The mold temperature is in the range of 50 to 150 ° C, preferably 70 to 130 ° C. Beyond that, the distortion increases, which is not desirable. On the other hand, if it is less than that, the cooling time becomes longer, which is not preferable. Thus, a transparent and tough molded product can be obtained. Transmittance, a measure of transparency, can be evaluated in terms of total light transmittance and haze value. The total light transmittance is preferably in the range of at least 88%, more preferably at least 90%. The haze value is preferably 5% or less, more preferably 3% or less. The glass transition temperature determined by the DSC method, which is a measure of heat resistance, is 130 ° C. or higher, preferably 135 ° C. or higher, and more preferably 140 ° C. or higher. The heat distortion temperature, which is another measure of heat resistance, is 100 ° C. or higher, preferably 105 ° C. or higher.

 According to the present invention, a hydrogenated styrene-based block copolymer excellent in heat resistance and transparency can be continuously produced efficiently and economically. This hydrogenated styrene-based block copolymer is excellent in transparency, heat resistance, and dimensional stability, and thus can be preferably used as an optical molding material for optical disks, lenses, and the like. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 shows an outline of one example of the production process of the present invention, and FIG. 2 shows the relationship between the conversion rate and the residence time in the production method of the present invention. Example

 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

 The raw materials, measuring methods, equipment, etc. used in the examples are as follows.

Polymer raw materials, catalysts, solvents, etc.>

Cyclohexane, methyl-tert-butyl ether, styrene and isoprene were all purified by distillation and used after drying sufficiently. The n-butyllithium and sec-butyllithium were used as they were using a 1.57 M n-hexane solution obtained from Kanto Idani Gaku. The hydrogenation catalyst Ni / silica / alumina catalyst (Ni loading: 65%) was purchased from A1 drich and used as is. _C- Tetramethoxysilane was purchased from Shin-Etsu Chemical Co., Ltd. A 3.0 weight hexane solution was prepared in a hexane solution, and a solution obtained by sufficiently dehydrating molecular sieve 4A in the solution was used. In this example, Sumilizer-1 GS (Sumitomo Chemical Co., Ltd.) was used. Used as stabilizer.

 Various physical property measurements performed in the examples were performed by the following methods.

 a) Glass transition temperature (Tg): Measured at a heating rate of 20 ° C / min using a Model 2920 DSC manufactured by TA Instruments.

 b) Hydrogenation rate, conjugated component content and microstructure: — Quantified by NMR. JEOL J NM—A—Measured using an A-400 nuclear magnetic resonance absorber.

 c) Molecular weight: Measured by gel permeation chromatography (Showa Denko KK, GPC, Shodex System-11) using tetrahydrofuran (THF) as a developing solvent to determine the molecular weight in terms of polystyrene.

 d) Total light transmittance: Measured using an ultraviolet-visible spectrometer (UV-240) manufactured by Shimadzu Corporation.

 e) Haze value: An automatic digital haze meter UDH-20D manufactured by Nippon Denshoku Industries Co., Ltd. was used. The sample used was a disk-shaped molded product with a thickness of 2 mm.

 f) Heat deformation temperature was measured based on JI SK7207 standard.

g) Transmission electron microscope observation was performed using JEOL JEM2010. The sample used was stained with osmic acid according to a conventional method. Static mixer Mean Effective area 10 one ⁴ m ^2, was used by connecting a static mixer Jacket Tsu Mounting length 0. 65 m in series. Kenics type was used as the type.

 A double plunger pump was used as a metering pump, and a monomer solution and an initiator solution were introduced. In the following embodiments, description will be given with reference to the manufacturing process shown in FIG.

 (Example 1) ''

A cyclohexane solution containing 20.6% by weight of styrene was placed in a storage tank maintained at 20 ° C. Meanwhile, a cyclohexane solution containing 0.167% by weight of sec-butyllithium was placed in a storage tank maintained at 20 ° C. From both storage tanks, through pre-mixing tank 3 maintained at 20 ° C via inlet pipes 1 and 2, the flow rate of the mixed solution was 7.1 / min, Styrene and sec-butyllithium were introduced into a piston flow type polymerization apparatus a maintained at 40 ° C under the condition of a molar ratio of 865: 1. At this time, the mass flow rate per average effective area in the Stuart mixer is 1.2 kg / m ² 's. Thereafter, a cyclohexane solution containing 22.4% by weight of isoprene was supplied from a storage tank maintained at 20 ° C. at a flow rate of 1.3 g / min through the inlet pipe 4 to the piston flow type polymerization apparatus a. The living styrene polymer solution was sent through a premixing tank 5 kept at 40 ° C. to a piston flow type polymerization apparatus b kept at 40 ° C. to carry out block copolymerization. Subsequently, a cyclohexane solution containing 20.6% by weight of styrene was kept at 20 ° C. via the inlet pipe 6 together with the styrene-isoprene block copolymer solution coming out of the piston flow type polymerization apparatus a. The mixture was introduced into the piston flow type polymerization apparatus c through the premixing tank 7 maintained at 40 ° C. at a flow rate of 6.5 g / in from the storage tank, and subjected to ternary block copolymerization.

A small amount of the styrene-isoprene-styrene triblock copolymer thus obtained was isolated, isolated by a conventional method, and analyzed. The ratio of styrene was 90.3% by weight, which almost coincided with 90% obtained from the introduction rate ratio. NMR analysis of the microstructure of the isoprene block revealed that the 1,4-structure was 94%, and the sum of the 1,2-structure and the 3,4-structure was 6%. Mn was 20 × 10 ⁴ , which was in good agreement with Mn determined from the molar ratio of the monomer involved in the polymerization and sec-butyllithium. The molecular weight distribution MwZMn was 1.05, indicating an extremely narrow dispersion. From this data, good piston flow was confirmed. In addition, as a result of observation of the block copolymer thus obtained by transmission electron microscopy, a sea-island structure in which islands of about 2 Onm in isoprene block component were uniformly dispersed in the sea of styrene block component was found. Admitted. No incorporation of bird structures of several hundred meters in which isoprene polymer was aggregated was observed.

The styrene-isoprene-styrene triblock copolymer thus obtained was introduced into a 50 L hydrogenation reactor d via a conduit 8. Ni / silica power as hydrogenation catalyst ■ Alumina catalyst was used at 5% by weight based on the copolymer solution, hydrogen pressure was 10 MPa, 180 ° C, and residence time was 20 hours. During the reaction, methyl-tert-butyl was added at a ratio of 1/3 of the weight of cyclohexane to prevent decomposition accompanying the hydrogenation reaction. Chilleter was added continuously. The amount of catalyst corresponding to the amount of catalyst continuously withdrawn with the reaction product was continuously replenished in the form of a slurry of methyl tert-butyl ether.

 The suspension of the hydrogenated styrene-based block copolymer thus obtained is filtered through a 0.1 m membrane filter Yuichi (“Fluoropore” manufactured by Sumitomo Electric Industries, Ltd.) to give a colorless and transparent solution. A hydrogenated styrene block copolymer solution was obtained. The solution was added with 0.4% of Sumilizer-GS, flashed, pelletized, and sent for analysis and molding.

The molecular weight Mw of the obtained hydrogenated styrene-based block copolymer was 14 × 10 ⁴ , and the water addition ratio was 96%. The glass transition temperature determined by DSC was 142 ° C, indicating high heat resistance. Using the obtained polymer pellet, injection molding was performed at a resin temperature of 300 ° C and a mold temperature of 75 ° C to obtain a transparent and strong molded product. The molded product having a thickness of 2 mm had a total light transmittance of 91% and a haze value of 2.5%, showing extremely high transparency. The heat distortion temperature was 109 ° C.

 A small amount of the polymerization solution was sampled in the middle of the piston flow polymerization apparatus a, and the relationship between the conversion and the residence time was examined. The conversion was determined by subjecting the extracted polymerization solution to gas chromatography and quantifying the unreacted styrene concentration. The results obtained are shown in FIG. As is clear from FIG. 2, the experimental values showed good agreement with the reaction using the cascade device consisting of a complete mixing tank with N = 10. In other words, it was proved that the reaction using this reactor was equivalent to a cascade device consisting of 10 complete mixing tanks. That is, extremely high piston flow properties were confirmed.

 (Example 2)

A cyclohexane methyl-tert-butyl-terl (2/1 by weight) solution containing 20.6% by weight of styrene was placed in a storage tank maintained at 20 ° C. Meanwhile, a cyclohexane solution containing 1.33% by weight of n-butyllithium was placed in a storage tank maintained at 20 ° C. Through a pre-storage mixing tank maintained at 20 ° C from both storage tanks, a flow rate of the mixed solution of 13.4 g / min and a molar ratio of styrene and sec-butyllithium of 54 1: 1 were brought to 40 ° C. Introduced into the kept piston flow type polymerization equipment a, The polymerization of ren was performed. At this time, the mass flow rate per average effective cross-sectional area in the STICK mixer is 2.2 kg / m ² 's. Thereafter, a cyclohexane / methyl-tert-butyl ether (2/1 by weight) solution containing 20.6% by weight of isoprene was discharged from a storage tank maintained at 20 ° C at a flow rate of 1.3 g / min. Along with the living styrene polymer solution sent from Type A polymerization device a, it was introduced into a piston flow type polymerization device b maintained at 40 ° C through a pre-mixing tank maintained at 40 ° C, and subjected to block copolymerization. The reaction was performed. Subsequently, a cyclohexane / methyl-tert-butyl ether (weight ratio: 2/1) solution containing 1.82% by weight of tetramethoxysilane was added together with the styrene-isoprene copolymer solution discharged from the polymerization apparatus B at 20 °. At a flow rate of 0.2 g / min from a storage tank maintained at C, the mixture was introduced into a Biston flow type polymerization apparatus c maintained at 60 ° C, and a radial reaction was performed.

A small amount of the styrene-isoprene radial block copolymer thus obtained was isolated, analyzed by a conventional method, and analyzed. The ratio of styrene was 90.5% by weight, which almost coincided with 90% obtained from the introduction speed ratio. The Mw corresponding to one branch was 6 × 10 ⁴ . In addition, the peaks of the spectrum obtained from GPC were separated, and the ratio of branching degree 4/3/2/1 was 7/60/13/20 and the radialization degree was 2.5. The peak-separated Mw / Mn was 1.02, which was an extremely narrow dispersion. C The NMR analysis of the microstructure of the isoprene block showed that the 1,4-bonds were 94%, 3, 4-1, and 1 , 2—The sum of the bonds was 6%. As a result of transmission electron microscopic observation of the radial block copolymer thus obtained, a sea-island structure in which islands of about 15 nm in size of isoprene component were uniformly dispersed in the sea of styrene component was observed. Island structure hundreds / m isoprene polymer was agglomerated was introduced at all recognized could not _c thus obtained styrene one isoprene radial block copolymer solution in a continuous water添槽of 50 L. Ni / silica / alumina catalyst was used as a hydrogenation catalyst in an amount of 5% by weight based on the weight of the copolymer solution, and hydrogen pressure was 10 MPa, 180 ° C., and residence time was 20 hours. The amount of catalyst corresponding to the amount of catalyst continuously withdrawn with the reaction product was continuously replenished in the form of a slurry of cyclohexane / methyl-tert-butyl ether (2/1).

The suspension of the hydrogenated styrene-based block copolymer thus obtained is subjected to opening 0 Filtration was performed using a l〃m membrane filter-1 (“Fluoropore” manufactured by Sumitomo Electric Industries, Ltd.) to obtain a colorless and transparent hydrogenated styrene-based block copolymer solution. The solution was added with 0.4% of Sumilizer-GS, flashed, pelletized, and sent for analysis and molding.

The resulting molecular weight Mw of hydrogenated styrene Purodzuku copolymer, 4 xl 0 ⁴ der is, water addition rate was 97%. The glass transition temperature determined by DSC was 144 ° C, indicating high heat resistance. Using the obtained polymer pellets, injection molding was performed at a resin temperature of 300 ° C and a mold temperature of 75 ° C to obtain a transparent and strong molded product. The total light transmittance of the molded product having a thickness of 2 mm was 91%, and the haze value was 2.7%, indicating extremely high transparency. The heat distortion temperature was 110 ° C.

 (Example 3)

A cyclohexane solution containing 20.6% by weight of styrene was placed in a storage tank maintained at 20 ° C. On the other hand, a cyclohexane solution containing 0.237% by weight of sec-butyllithium was placed in a storage tank maintained at 20 ° C. Through a pre-storage mixing tank maintained at 20 ° C from both storage tanks, the flow rate of the mixed solution was 9.6 g / min, and the molar ratio of styrene to sec-butyllithium was 577: 1 and the temperature was increased to 40 ° C. It was introduced into the kept piston flow type polymerization apparatus a. At this time, the mass flow rate per average effective cross-sectional area in the STICK mixer is 1.6 kgZm ² 's. Thereafter, a cyclohexane solution containing 20.6% by weight of styrene and 19.8% by weight of isoprene was transferred from a storage tank maintained at 20 ° C at a flow rate of 20.4 g / min to a piston flow type polymerization apparatus. Through the premixing tank kept at 40 ° C together with the styrene polymer solution sent from a, it was introduced into a piston flow type polymerization apparatus b kept at 40 ° C.

A small amount of the thus obtained gradient styrene-isoprene-styrene terpolymer was isolated, analyzed by a conventional method, and analyzed. The ratio of styrene was 89.0% by weight, which almost coincided with 90% obtained from the introduction rate ratio. Mw was 20 × 10 ⁴ , which was in good agreement with Mn obtained from the molar ratio of the monomer involved in the polymerization and sec-butyllithium. Its molecular weight dispersion Mw / Mn was 1.08, indicating an extremely narrow dispersion. Even from this day, good piston flow was confirmed. Observation of the block copolymer thus obtained by transmission electron microscopy As a result, a sea-island structure was observed in which the isoprene component islands of about 15 nm dogs were uniformly dispersed in the sea composed of styrene components. No island structure of several hundred m in which the isoprene polymer was aggregated was observed at all.

 The inclined styrene-isoprene-styrene ternary block copolymer thus obtained was introduced into a 50 L stainless steel continuous hydrogenation tank. Ni / silica-alumina catalyst was used as a hydrogenation catalyst, and hydrogen pressure was 10 MPa, 180 ° C, and residence time was 20 hours. At the time of the reaction, methyl-tert-butyl ester was continuously added at a ratio of 1/3 of the weight of the cyclic hexane in order to prevent decomposition accompanying the hydrogenation reaction. An amount of catalyst corresponding to the amount of catalyst continuously withdrawn with the reaction product was continuously replenished in the form of slurry of methyl-tert monobutyl ether.

 The suspension of the hydrogenated styrene-based block copolymer thus obtained is filtered through a 0.1 l〃m membrane filter (“Fluoropore” manufactured by Sumitomo Electric Industries, Ltd.) to give a colorless and transparent solution. A hydrogenated styrene-based block copolymer solution was obtained. The solution was flushed with 0.4% of Sumilizer-GS, flushed, pelletized, and sent for analysis and molding.

The molecular weight Mw of the obtained hydrogenated styrene-based block copolymer was 14 × 10 ^4, and the water addition ratio was 96%.

 The glass transition temperature determined by DSC was 138 ° C, indicating high heat resistance. Using the obtained polymer pellet, injection molding was performed at a resin temperature of 300 ° C and a mold temperature of 75 ° C to obtain a transparent and strong molded product. The molded product having a thickness of 2 mm had a total light transmittance of 91% and a haze value of 1.5%, showing extremely high transparency. The heat distortion temperature was 105 ° C.

Claims

The scope of the claims 1. The following steps (1) to (4):  (1) A styrene-based monomer solution and an anion polymerization initiator solution are continuously introduced at a predetermined ratio into a piston flow type polymerization apparatus (polymerization apparatus a) comprising one or more static mixers. Polymerizing until the polymerization initiator is substantially consumed (polymerization step A),  (2) A piston composed of one or more static mixers in a predetermined ratio of the polymer solution obtained in the polymerization step A, a conjugated gen or a solution of the conjugated gen, and a styrene-based monomer solution as required. A step of continuously introducing into a flow type polymerization apparatus (polymerization apparatus b) to perform block copolymerization (polymerization step B);  (3) If necessary, the block copolymer solution obtained in the polymerization step B and the styrene-based monomer solution at a predetermined ratio in one or more static mixers consisting of one or more static mixers. (Polymerization step C), a step of continuously introducing into the polymerization apparatus c) and copolymerizing the block (polymerization step C), and  () The block copolymer solution obtained in the polymerization step B or the polymerization step C is continuously introduced into the hydrogenation apparatus, and the aromatic group and the c = c double bond in the copolymer are hydrogenated. Hydrogenation in the presence of an added catalyst (hydrogenation step), For continuously producing a hydrogenated styrenic block copolymer comprising: 2. The following processes (1,) to (4,):  () A styrene-based monomer solution and an anion polymerization initiator solution are continuously introduced at a predetermined ratio into a piston flow type polymerization apparatus (polymerization apparatus a) comprising one or more stick mixers, and Polymerizing until the anion polymerization initiator is substantially consumed (polymerization step A);  (2,) The polymer solution obtained in the polymerization step A and the conjugated gen or a solution of the conjugated gen at a predetermined ratio are provided in a piston-hole type polymerization apparatus comprising one or more stick mixers. A step of continuously introducing into the apparatus b ′) to perform block copolymerization (polymerization step B,), (3) The block copolymer solution obtained in the polymerization step B and the functional group having three or more functional groups A step of introducing a radiating agent solution having a predetermined ratio into a piston flow type reaction device (radialization device) comprising one or more stick mixers to perform a radialization reaction (radialization step) ) , and  (4,) The radial block copolymer solution obtained in the radialization step is continuously introduced into a hydrogenation device, and the aromatic group and C = C double bond contained in the copolymer are hydrogenated. Hydrogenation in the presence of an added catalyst (hydrogenation step), A continuous method for producing a hydrogenated styrene block copolymer comprising:  3. In the polymerization step A, the styrene monomer solution and the anion polymerization initiator solution which are premixed are used as the styrene monomer solution and the anion polymerization initiator solution. Item 3. A method for continuous production of a hydrogenated styrene block copolymer according to item 1 or 2.  4. Cool the mixing element of the mixer in which the styrene-based monomer solution and the anion polymerization initiator solution are continuously introduced in the polymerization apparatus a, or immediately before the mixer. 3. The method for continuously producing a hydrogenated styrene-based block copolymer according to claim 1, wherein a cooled static mixer is provided. 5. The average effective area of the static mixer, 1 0- ⁴ m ² ~lm ² a is請Motomeko 1-4 Les continuous Manufacturing hydrogenated styrenic block copolymer according to item 1 Zureka Method. 6. Mass flow per average effective sectional area of the static mixer, lk gZm ² • s~1 0 ³ hydrogen Kas styrene system according to any one of claims 1 to 5 which is kg / m ² · s A continuous production method of block copolymer.  7. The method for continuously producing a hydrogenated styrene-based block copolymer according to claim 1 or 2, wherein the hydrogenation rate of the hydrogenated styrene-based block copolymer is 95% or more. 8. The average molecular weight Mw of the hydrogenated styrene-based block copolymer is 100000 or more and 400.000 or less, and the molecular weight distribution Mw / Mn is 1.0 to 1.3. 2. The continuous production method of the hydrogenated styrene block copolymer according to 1.  9. Average molecular weight Mw of hydrogenated styrene-based block copolymer is 10,000,000 or more 3. The water according to claim 2, wherein the water is 400, 000 or less, and the degree of radialization is 2.1 or more. A method for continuously producing a hydrogenated styrene block copolymer.  10. The continuous production of a hydrogenated styrene block copolymer according to claim 8 or 9, wherein the content of the hydrogenated styrene polymer block contained in the copolymer is 70 to 99% by weight. Method.  11. The method for continuously producing a hydrogenated styrene-based copolymer according to claim 10, wherein the copolymer is substantially free of a hydrogenated gen-based polymer.  12. The continuous production method for a hydrogenated styrene-based block copolymer according to claim 10, wherein the glass transition temperature of the copolymer is 130 ° C or higher.  13. A hydrogenated styrenic block copolymer obtained by the method according to claim 1 or 2.  14. An optical molding material comprising a hydrogenated styrene-based block copolymer obtained by the method according to claim 1 or 2.  15. The optical molding material according to claim 14, wherein the total light transmittance is 88% or more and the haze value is 5% or less.  16. The optical molding material according to claim 14, wherein the heat distortion temperature is 100 ° C or more.