JP3580020B2 - Process for producing block copolymer and hydrogenated product thereof - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a block copolymer in which the amount of gel contained in the block copolymer is small when the block copolymer is repeatedly polymerized by a batch polymerization method.
[0002]
[Prior art]
Block copolymers consisting of conjugated dienes and vinyl aromatic hydrocarbons are transparent and have the same properties as vulcanized natural or synthetic rubbers without vulcanization when the content of vinyl aromatic hydrocarbons is relatively low. Since it has elasticity at room temperature and has the same processability as thermoplastic resin at high temperatures, it is widely used in the fields of footwear, plastic modification, asphalt, adhesive and the like. Block copolymers having a relatively high content of vinyl aromatic hydrocarbons are resins having excellent transparency and impact resistance, and are therefore widely used in sheets, films, injection molded products and the like. .
[0003]
Methods for producing these block copolymers have been known for a long time, and examples thereof include JP-B-36-19286, JP-B-40-23798, JP-B-43-17979, JP-B-48-4106, There are JP-A-53-94584, JP-A-51-46391, and the like. These block copolymers composed of a vinyl aromatic hydrocarbon and a conjugated diene are produced by a batch polymerization method, and after adding the entire amount of the catalyst to the polymerization reactor and then adding the monomer, or after adding the monomer to the polymerization reactor and then adding the monomer. There is a method of adding the entire amount of the catalyst. JP-A-53-286 describes a method for producing a resinous monovinyl-substituted aromatic compound and a conjugated diene copolymer by using a monovinyl-substituted aromatic compound and a multi-stage addition of an initiator. Japanese Patent Publication No. 17407/1985 discloses a production method in which a part of monomers forming a block copolymer is produced in advance by a batch method, and then the remaining monomer is continuously polymerized.
[0004]
[Problems to be solved by the invention]
In a conventional method for producing a block copolymer by a batch polymerization method, a monomer and a catalyst for forming a block copolymer are added to a polymerization reactor, and after the polymerization is started, the same polymerization reactor is used until the polymerization is completed. . In such a batch polymerization method, when the polymerization is to be started at a relatively high temperature, the amount of gel contained in the polymer increases with the increase in the number of polymerization batches.
[0005]
[Means for Solving the Problems]
That is, the present invention provides, in a hydrocarbon solvent, a block copolymer comprising at least one polymer block mainly composed of a conjugated diene and at least one polymer block mainly composed of a vinyl aromatic hydrocarbon or a block copolymer thereof. In producing the additive by the batch polymerization method,
(A) After producing an active polymer using a vinyl aromatic hydrocarbon which forms a block copolymer in advance with an organolithium compound as a catalyst,
(B) The active polymer solution is transferred to a polymerization reactor different from the polymerization reactor in which it was produced, and then the remaining conjugated diene or vinyl aromatic hydrocarbon or conjugated diene and vinyl aromatic hydrocarbon are sequentially added to carry out polymerization. (C) hydrogenating the conjugated diene portion of the block copolymer obtained in (b) to obtain a hydrogenated product. And a method for producing a hydrogenated product of a block copolymer.
[0006]
Hereinafter, the present invention will be described in detail.
The content of the vinyl aromatic hydrocarbon in the block copolymer of the present invention is 10 to 95% by weight, preferably 15 to 90% by weight, and is a block copolymer of a conjugated diene and a vinyl aromatic hydrocarbon. If the vinyl aromatic hydrocarbon content of the block copolymer is out of this range, the properties of the block copolymer are not exhibited, which is not preferable.
[0007]
The block copolymer of the present invention has a general formula:
A1- (B-A2) _n , A1- (B-A2) _n- B,
[A1- (B-A2) _k ] _{m + 2-} X
Is a linear block copolymer or a radial block copolymer represented by the following formula, or a mixture of any polymer structures of these block copolymers.
[0008]
In the above general formula, A1 and A2 are polymer blocks mainly composed of vinyl aromatic hydrocarbon, and B is a polymer block mainly composed of conjugated diene. The boundary between the A block and the B block does not necessarily need to be clearly distinguished. n, k and m are 1-5. X is a residue of a coupling agent. Examples of the coupling agent include silicon tetrachloride, tin tetrachloride, and 1,3 bis (N, N-glycidylaminomethyl) cyclohexane.
[0009]
Here, a polymer block mainly composed of a vinyl aromatic hydrocarbon represented by A1 or A2 in the general formula refers to a copolymer of a vinyl aromatic hydrocarbon having a vinyl aromatic hydrocarbon content of 50% by weight or more and a conjugated diene. A copolymer block and / or a vinyl aromatic hydrocarbon homopolymer block is shown. Preferred A1 is a vinyl aromatic hydrocarbon homopolymer block. The compositions of the vinyl aromatic hydrocarbons and conjugated dienes of A1 and A2 and the weights of A1 and A2 may be the same or different. The polymer block mainly composed of a conjugated diene represented by B in the general formula means a conjugated diene containing a conjugated diene in an amount exceeding 50% by weight and a vinyl aromatic hydrocarbon copolymer block and / or a conjugated diene homopolymer. Shows the coalescing block.
[0010]
When a random copolymer portion of a vinyl aromatic hydrocarbon and a conjugated diene is present in a polymer block mainly composed of a vinyl aromatic hydrocarbon or a polymer block mainly composed of a conjugated diene, Aromatic hydrocarbons may be distributed uniformly in the polymer block or may be distributed in a tapered (decreasing) form. The copolymer portion may include a plurality of portions where vinyl aromatic hydrocarbons are uniformly distributed and / or a plurality of portions where the vinyl aromatic hydrocarbons are distributed in a tapered shape.
[0011]
The greatest feature of the present invention is that an active polymer of a vinyl aromatic hydrocarbon which forms a block copolymer in advance using an organolithium compound as a catalyst is produced, transferred to another polymerization vessel, and blocked by batch polymerization. To produce a copolymer. The active polymer may be part or all of the vinyl aromatic hydrocarbon forming the block copolymer.
[0012]
The active polymer of the present invention is a polymer in which the terminal of the polymer has a living anion terminal. The molecular weight of the active polymer is not particularly limited, but preferably the number average molecular weight (Mn) is 300 to 200,000. If Mn is less than 300, the amount of gel contained in the block copolymer obtained by increasing the number of polymerization batches increases, and if it exceeds 200,000, the properties of the obtained block copolymer deteriorate, which is not preferable.
[0013]
The step (a) of the present invention may be produced using a batch-type vessel-type reactor with a stirrer or a continuous-type disperser such as a pipeline homomixer or a static mixer. The number average molecular weight in the step (a) is determined by preparing a calibration curve between the peak count number and the number average molecular weight of the monodisperse polystyrene by gel permeation chromatography (GPC). "Gel chromatography <basic>" published by Kodansha).
[0014]
Step (b) of the present invention is performed using a batch polymerization method. The batch polymerization method of the present invention means that after the active polymer (a) is transferred to a polymerization vessel, the remaining conjugated diene or vinyl aromatic hydrocarbon or the conjugated diene and vinyl aromatic hydrocarbon are sequentially added, This is a method of taking out the produced block copolymer in the polymerization vessel after the supply of the monomer is completed. The addition of the conjugated diene and the vinyl aromatic hydrocarbon in the step (b) may be continuously performed at a constant flow rate using a pump, or may be performed in a short period of 0.1 to 5 minutes.
[0015]
Examples of the vinyl aromatic hydrocarbon used in the present invention include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, , 1-diphenylethylene and the like, with styrene being particularly preferred. These may be used alone or in combination of two or more.
[0016]
The conjugated diene is a diolefin having a pair of conjugated double bonds, for example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene. , 1,3-pentadiene, 1,3-hexadiene and the like, and particularly preferably 1,3-butadiene and isoprene. These may be used alone or in combination of two or more.
[0017]
Examples of the hydrocarbon solvent include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, and octane; cycloaliphatic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane; and benzene and toluene. And aromatic hydrocarbons such as ethylbenzene and xylene. These may be used alone or in combination of two or more.
[0018]
The organic lithium compound is an organic monolithium compound, an organic dilithium compound, or an organic polylithium compound in which one or more lithium atoms are bonded in a molecule. Specific examples of these include ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, hexamethylene dilithium, butadienyl dilithium, isoprenyl dilithium and the like. No. These may be used alone or in combination of two or more.
[0019]
In the present invention, the polymerization rate is adjusted in both or any of the steps (a) and (b), the microstructure (ratio of cis, trans, and vinyl) of the polymerized conjugated diene is changed, and the conjugated diene and vinyl aromatic carbon A polar compound or a randomizing agent can be used for the purpose of adjusting the reaction ratio of hydrogen and the like.
[0020]
Examples of polar compounds and randomizers include tetrahydrofuran, diethylene glycol dimethyl ether, ethers such as diethylene glycol dibutyl ether, triethylamine, amines such as tetramethylethylenediamine, thioethers, phosphines, phosphoramides, alkylbenzene sulfonates, potassium and sodium salts. Alkoxide and the like.
[0021]
The polymerization temperature for producing the block copolymer in the method of the present invention is generally 30C to 120C, preferably 40C to 100C. The time required for the polymerization varies depending on the conditions, but is usually within 10 hours, particularly preferably 0.5 to 5 hours. Further, it is desirable to replace the atmosphere of the polymerization system with an inert gas such as nitrogen gas. The polymerization pressure is not particularly limited, as long as it is a pressure range sufficient to maintain the monomer and the solvent in a liquid phase within the above-mentioned polymerization temperature range. Further, it is necessary to take care that impurities such as water, oxygen, carbon dioxide, etc., which inactivate the catalyst and the living polymer, do not enter the polymerization system.
[0022]
The weight average molecular weight of the block copolymer thus obtained is generally 10,000 to 500,000, preferably 30,000 to 300,000. The amount of the hydrocarbon solvent in the block copolymer solution is generally 50 parts by weight to 2,000 parts by weight based on 100 parts by weight of the block copolymer.
[0023]
As the hydrogenated product of the block copolymer of the present invention, a block copolymer partially or selectively hydrogenated by a hydrogenation reaction (hydrogenation reaction) can be used. In the hydrogenation reaction, if necessary, the active terminal of the block copolymer solution may be inactivated by a step of adding a reaction terminator, or may be performed with the active terminal remaining.
[0024]
The hydrogenation rate of the hydrogenation reaction of the present invention can be arbitrarily selected, and when improving the heat deterioration resistance while maintaining the properties of the unhydrogenated block copolymer, an aliphatic double based on a conjugated diene is used. Hydrogenate the bond by 3% or more, less than 80%, preferably 5% or more, and less than 75%, or hydrogenate it by 80% or more, preferably 90% or more in order to improve the heat deterioration resistance and weather resistance. It is recommended that
[0025]
The hydrogenation rate can be measured by a nuclear magnetic resonance apparatus or the like. Examples of the catalyst used for the hydrogenation reaction include (1) a supported heterogeneous catalyst in which a metal such as Ni, Pt, Pd, and Ru is supported on a carrier such as carbon, silica, alumina, and diatomaceous earth; ) A so-called Ziegler-type catalyst using an organic salt such as Ni, Co, Fe, Cr or the like or an acetylacetone salt and a reducing agent such as organic Al, or a so-called organic complex catalyst such as an organic metal compound such as Ru or Rh, or a titanocene compound. A homogeneous catalyst using organic Li, organic Al, organic Mg or the like as a reducing agent is known. Specific methods include the methods described in JP-B-42-8704 and JP-B-43-6636, preferably the methods described in JP-B-63-4841 and JP-B-63-5401. And hydrogenation of the block copolymer in an inert solvent in the presence of a hydrogenation catalyst.
[0026]
The block copolymer of the present invention can be blended with various thermoplastic resins as needed to form a resin composition. Examples of thermoplastic resins that can be used include polystyrene-based polymers, polyphenylene ether-based polymers, polyethylene-based polymers, polypropylene-based polymers, polybutene-based polymers, polyvinyl chloride-based polymers, polyvinyl acetate-based polymers, Polyamide-based polymer, thermoplastic polyester-based polymer, polyacrylate-based polymer, polyphenoxy-based polymer, polyphenylene sulfide-based polymer, polycarbonate-based polymer, polyacetal-based polymer, polybutadiene-based polymer, thermoplastic polyurethane-based polymer Coalesce, a polysulfine-based polymer and the like, and a preferred thermoplastic resin is a styrene-based polymer, and particularly, a polystyrene resin, a styrene-butyl acrylate copolymer, and a styrene-methyl methacrylate copolymer can be suitably used. .
[0027]
The resin composition containing the block copolymer of the present invention may optionally contain optional additives. The type of additive is not particularly limited as long as it is generally used for compounding plastics. For example, glass fiber, glass beads, silica, charcoal, inorganic reinforcing agents such as talc, organic fibers, cumarone indene Organic reinforcing agents such as resins, crosslinking agents such as organic peroxides and inorganic peroxides, pigments such as titanium white, carbon black and iron oxide, dyes, flame retardants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, Plasticizers, other extenders or mixtures thereof.
[0028]
In the present invention, a composition in which a block copolymer and a thermoplastic resin are blended can be produced by any conventionally known blending method. For example, an open roll, an intensive mixer, an internal mixer, a co-kneader, a continuous kneader with a twin-screw rotor, a melt kneading method using a general kneader such as an extruder, etc. A method of heating and removing the solvent is used.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Examples of the present invention will be described below in order to explain the embodiments of the present invention in further detail, but the content of the present invention is not limited to these examples.
[0030]
【Example】
Example 1 and Comparative Example 1
<Production of active polymer>
400 parts by weight of cyclohexane, 100 parts by weight of styrene, 6.2 parts by weight of n-butyllithium (hereinafter referred to as nBL), and 3 parts by weight of tetramethylethylenediamine were added to pressure-resistant autoclave A, and completely reacted at 40 ° C. Mn of the obtained polystyrene active polymer (hereinafter referred to as C1) was measured by gel permeation chromatography (GPC) to find that it was 1100.
[0031]
<Production of block copolymer>
After adding 300 parts by weight of cyclohexane to the autoclave B equipped with a stirrer and a jacket, the internal temperature was raised to 85 ° C. Next, C1 was added in an amount equivalent to 0.067 parts by weight of nBL, and 13 parts by weight of styrene was added, followed by polymerization under stirring for about 15 minutes. Thereafter, 28 parts by weight of 1,3-butadiene (hereinafter referred to as butadiene) and 27 parts by weight of styrene were continuously added to the autoclave by a micro motion flow meter for 100 minutes, and after the supply was completed, the mixture was stirred for about 5 minutes. Left. Next, 32 parts by weight of styrene were continuously added to the autoclave by a micro motion flow meter for 25 minutes, and after completion of the supply, the mixture was left under stirring for about 10 minutes.
[0032]
After the polymerization reaction, methanol was added to the autoclave at a molar ratio of 0.9 times the molar number of nBL to the autoclave to terminate the polymerization, and then the methanol was extracted from the autoclave. The autoclave after the extraction was not washed, and the next polymerization was repeated in the same procedure, and 20 batch polymerizations were repeated. 2- (2-hydroxy-3-t-butyl-5-methylbenzyl) -4-methyl-6-t-butylphenyl acrylate and trisnonylphenyl phosphite were added to the block copolymer in an amount of 100 wt. 0.5 part by weight per part as a stabilizer was added, and cyclohexane as a solvent was distilled off by heating to obtain a block copolymer A.
[0033]
For comparison, 300 parts by weight of cyclohexane was added to the autoclave B of Example 1, and the internal temperature was raised to 85 ° C. Next, 0.067 parts by weight of nBL and 13 parts by weight of styrene were added, and then the polymerization was carried out with stirring for about 20 minutes. A copolymer was obtained (block copolymer B). Next, 50 g of the obtained block copolymer was dissolved in 200 ml of toluene, and suction-filtered with a 70 mm-diameter filter paper (thickness: 0.2 mm, retained particle diameter: 6 μm, collection efficiency: 65%). After dyeing the residue in step 36) and allowing to stand for 5 minutes, the gel amount of the filter paper was visually determined according to the following criteria.
[0034]
◎: Large number is 0, or medium is 3 or less, or small is 5 or less ：: Large number is 0, or medium is 4 to 10, or small is 6 to 20 △: large is The number is 1 or 11 to 20 in the middle, or 21 to 40 in the small x: 2 or more in the large, 21 or more in the middle, or 41 or more in the small (the small has a diameter of 0. (Less than 2 mm, medium diameter 0.2-0.5 mm, large diameter more than 0.5 mm)
As a result, the block copolymer B was excellent, and the block copolymer A was excellent, as compared with △.
[0035]
Example 2 and Comparative Example 2
<Production of active polymer>
300 parts by weight of cyclohexane, 20 parts by weight of styrene, and 0.11 part by weight of nBL were added to the pressure-resistant autoclave A, and completely reacted at 80 ° C. Mn of the obtained polystyrene active polymer (hereinafter, referred to as C2) was measured by gel permeation chromatography (GPC) to find that it was 12,000.
[0036]
<Production of block copolymer>
After transferring the entire amount of C2 to the autoclave B equipped with a stirrer and a jacket, the temperature was set to 85 ° C., and 40 parts by weight of butadiene were continuously added to the autoclave by a micro motion flow meter for 50 minutes, and the supply was completed. After that, it was left under stirring for about 5 minutes. Next, 20 parts by weight of styrene were continuously added to the autoclave for 25 minutes with a micro motion flow meter, and the mixture was left under stirring for about 10 minutes, and then methanol was added to the autoclave at a molar ratio of 0.9 times the number of moles of nBL. Then, the polymerization was stopped, and the mixture was taken out of the autoclave.
[0037]
The autoclave after the extraction was not washed, and the next polymerization was repeated in the same procedure, and 15 batch polymerizations were repeated. 2- (2-hydroxy-3-t-butyl-5-methylbenzyl) -4-methyl-6-t-butylphenyl acrylate and trisnonylphenyl phosphite were added to the block copolymer in an amount of 100 wt. 0.5 part by weight per part as a stabilizer was added, and cyclohexane as a solvent was distilled off by heating to obtain a block copolymer C.
[0038]
Next, for comparison, after adding 300 parts by weight of cyclohexane to the autoclave B of Example 2, the internal temperature was raised to 80 ° C. Next, after adding 0.11 part by weight of nBL and 20 parts by weight of styrene, the block copolymer after the same procedure and the same number of polymerizations as in <Production of block copolymer> of Example 2 except that polymerization was carried out under stirring for about 20 minutes. A polymer was obtained (block copolymer D). The gel amount of the obtained block copolymer was determined in the same manner as in Example 1 except that the weight of the block copolymer was 10 g. As a result, the block copolymer C was ○ while the block copolymer D was ×.
[0039]
Example 3
<Production of active polymer>
300 parts by weight of cyclohexane, 9 parts by weight of styrene, 0.06 parts by weight of nBL and 0.06 parts by weight of tetramethylethylenediamine were added to the pressure-resistant autoclave A, and the mixture was completely reacted at 75 ° C. Mn of the obtained polystyrene active polymer (hereinafter referred to as C3) was measured by gel permeation chromatography (GPC) to find that it was 9300.
[0040]
<Production of hydrogenated block copolymer>
After transferring the entire amount of C3 to the autoclave B equipped with a stirrer and a jacket, 82 parts by weight of butadiene were continuously added to the autoclave by a micro motion flow meter for 60 minutes, and after the supply was completed, the mixture was stirred for about 5 minutes. Left. Next, 9 parts by weight of styrene were continuously added to the autoclave with a micro motion flow meter for 10 minutes, and the mixture was left under stirring for about 10 minutes, and then methanol was added at a molar ratio of 0.9 times the molar number of nBL. To complete the polymerization to obtain a block copolymer.
[0041]
Next, a cyclohexane solution (about 1% by weight) containing 0.5 parts by weight of bis (cyclopentadienyl) titanium dichloride as the hydrogenation catalyst component (a) and 0.54 parts by weight of nBL as the hydrogenation catalyst component (b) ) Was mixed under hydrogen, the whole amount was added to the block copolymer solution, and a hydrogenation reaction was carried out at 70 ° C under stirring at a hydrogen pressure of 5.0 kg / cm ² G for about 1 hour, and the butadiene part was reacted. A hydrogenated block copolymer having a hydrogenation rate of 97% was obtained.
[0042]
Next, methanol was added to the autoclave at a molar ratio of 0.9 times the number of moles of nBL used as the hydrogenation catalyst component, and extracted from the autoclave. The autoclave after the extraction was not washed, and the next polymerization and hydrogenation were repeated in the same procedure, and 15 batch polymerizations were repeated. To this block copolymer, 2- (2-hydroxy-3-t-butyl-5-methylbenzyl) -4-methyl-6-t-butylphenyl acrylate and trisnonylphenyl phosphite were each added in an amount of 100 wt. 0.2 parts by weight per part as a stabilizer was added, and cyclohexane as a solvent was distilled off by heating to obtain a block copolymer E. The gel amount of the obtained block copolymer was determined by the same method as in Example 2, and as a result, the block copolymer E was ○.
[0043]
【The invention's effect】
In the present invention, (a) after producing an active polymer in advance, (b) transferring this active polymer solution to another polymerization vessel, and producing a block copolymer by batch polymerization, thereby obtaining a block copolymer. A block copolymer containing a small amount of gel is obtained.

Claims (4)

In producing a block copolymer comprising at least one polymer block mainly composed of conjugated diene and at least one polymer block mainly composed of vinyl aromatic hydrocarbon in a hydrocarbon solvent by a batch polymerization method. ,
(A) After producing an active polymer using a vinyl aromatic hydrocarbon which forms a block copolymer in advance with an organolithium compound as a catalyst,
(B) The active polymer solution is transferred to a polymerization reactor different from the polymerization reactor in which it was produced, and then the remaining conjugated diene or vinyl aromatic hydrocarbon or conjugated diene and vinyl aromatic hydrocarbon are sequentially added to carry out polymerization. A method for producing a block copolymer, which is finished. In producing a block copolymer comprising at least one polymer block mainly composed of conjugated diene and at least one polymer block mainly composed of vinyl aromatic hydrocarbon in a hydrocarbon solvent by a batch polymerization method. ,
(A) After producing an active polymer using a vinyl aromatic hydrocarbon which forms a block copolymer in advance with an organolithium compound as a catalyst,
(B) The active polymer solution is transferred to a polymerization reactor different from the polymerization reactor in which it was produced, and then the remaining conjugated diene or vinyl aromatic hydrocarbon or conjugated diene and vinyl aromatic hydrocarbon are sequentially added to carry out polymerization. After finishing and obtaining the block copolymer,
(C) A method for producing a hydrogenated product of a block copolymer, comprising hydrogenating a conjugated diene portion of the block copolymer to obtain a hydrogenated product. The block copolymer has a general formula,
A1- (B-A2) _n , A1- (B-A2) _n- B,
[A1- (B-A2) _k ] _{m + 2-} X
(In the above formula, A1 and A2 are polymer blocks mainly composed of vinyl aromatic hydrocarbons, and B is a polymer block mainly composed of conjugated diene. The boundary between the A block and the B block is not necessarily clear. No distinction is required; n, k and m are 1 to 5. X represents the residue of the coupling agent.)
The method for producing a block copolymer according to claim 1, wherein The method for producing a block copolymer according to claim 3, wherein A1 of the block copolymer is a polymer block of a vinyl aromatic hydrocarbon alone.