JP3608638B2 - Selectively hydrogenated symmetric linear block copolymers containing blocks derived from polar vinyl monomers and methods for their preparation - Google Patents

Description

【００４９】
実施例６〜８
ＰＭＭＡ−ＳＢＳ−ＰＭＭＡブロックコポリマーの合成
リビングＬｉ−ＳＢＳ−Ｌｉトリブロックコポリマーの溶液を実施例２の方法を使用して合成した。スチレン重合完了後、ジフェニルエチレンの０．５モルのシクロヘキサン溶液１２ｍｌを添加した。末端キャッピング反応を室温で３０分続けた。次いで、赤色溶液を０℃に冷却し、１ｌの脱水テトラヒドロフランを添加し、溶液を−７８℃に冷却した。この温度で、４．８ｇのメチルメタクリレートを導入すると、無色透明の溶液が得られた。重合を３０分続けた後、１ｍｌのメタノールを導入して重合を停止した。回収したポリマーを酸化防止剤で安定化すると、表ＩＩに示す特徴を示した。
【００５０】
【表２】

【００５１】
実施例９〜１２
ＰＴＢＭＡ−ＳＢＳ−ＰＴＢＭＡブロックコポリマーの合成
ＭＭＡをＴＢＭＡ（ｔ−ブチルメタクリレート）で置き換えた他は実施例６〜８に記載の方法と同様にして、これらのブロックコポリマーを合成した。これらのブロックコポリマーの特徴を表 ＩＩＩに示す。
【００５２】
【表３】

【００５３】
実施例１３〜１６
水素添加したＰＭＭＡ−ＳＢＳ−ＰＭＭＡブロックコポリマーおよび水素添加したＰＴＢＭＡ−ＳＢＳ−ＰＴＢＭＡブロックコポリマーの合成
実施例６〜８に従って得たリビングＬｉ−ＰＭＭＡ−ＳＢＳ−ＰＭＭＡ−Ｌｉブロックコポリマーの溶液および実施例９で得たリビングＬｉ−ＰＴＢＭＡ−ＳＢＳ−ＰＴＢＭＡ−Ｌｉブロックコポリマーの溶液を各々、メタノールおよび水素ガスで処理し、停止させたブロックコポリマー溶液を次いで、アルミニウム／コバルト、アルミニウム／ニッケルおよびチタンジシクロペンタジエニルから選択される一般に公知のいくつかの水素添加触媒を使用して、実質的に水素添加した（ＲＵ≦５％）。得られたブロックコポリマーの特徴を表ＩＶに示し、構造的に関連する市販のブロックコポリマーグレードと比較した。
【００５４】
【表４】

【００５５】
^ａ ＫＲＡＴＯＮ Ｇ−１６５４ （商標）、ポリ（スチレン）−ポリ（エチレン−ブチレン）−ポリスチレンブロックコポリマーを含むブロックコポリマーグレードであり、ポリ（エチレン−ブチレン）ブロックのエチレン性残留不飽和度は１％未満である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to selectively hydrogenated symmetrical linear block copolymers comprising blocks derived from conjugated dienes, monovinyl aromatics and / or polar vinyl monomers, and processes for their preparation.
[0002]
In particular, the invention relates to lower alkyl acrylates or methacrylate esters, 2- or 4-vinylpyridine, maleic acid, fumaric acid, itaconic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, endo-cis-bicyclo (2 , 2,1) -5 hydrogen containing blocks derived from polar vinyl monomers such as esters or anhydrides of 5-heptene-2,3-dicarboxylic acid or mixtures thereof, and internal blocks derived from conjugated dienes and optionally monovinyl aromatics It relates to added symmetrical linear block copolymers, as well as to their preparation using improved dilithio initiators.
[0003]
[Prior art]
To date, for example, US Pat. 3,653,516; 3,734,973; 3,663,634; 3,694,516; 3,668,263; 3,903,168; 3,954,894; 4,039,593; 172,100; 4,182,818; 4,960,842; European patent application no. 0316857; 0413294; 0599671 and Macromolecules 5, 453-8 (1969); P. Foss et al., Macromolecules 12, 344-6 (1979); W. Kamienski et al., Curr. Appl. Sci. Med. Technol. 315-25 (1985); P. Foss et al., Moolemolecules 10, 287-291 (1977) and Macromolecules 12, 1210-1216 (1979); Polymer 23, 1953-9 (1982); E. long et al., J. MoI. Polym. Sci. Part A. Polym. Chem. vol. 27, 4001-4012 (1989), several proposals have been made for the production of dilithium organo compounds for the anionic polymerization of monovinyl aromatic and / or conjugated diene monomers to obtain block copolymers. It was done.
[0004]
Although the use of dilithioinitiators for the production of symmetrical linear block copolymers that must exhibit the desired narrow molecular weight distribution has been disclosed, to date, for a number of practical reasons, the diinitiators No actual commercial polymerization process has been developed through the use of.
[0005]
In general, it has been recognized that most of the proposed methods require the use of polar compounds such as amines or ethers, in which case the vinyl content of the poly (conjugated diene) block becomes too high and the Such block copolymers cannot be used in end uses that require good low temperature performance.
[0006]
The desired narrow molecular weight distribution of linear symmetric block copolymers, required for more modern sophisticated end uses, could not be achieved with a consistent and reliable quality.
[0007]
On the other hand, those skilled in the art will find that the symmetrical linear block copolymer containing terminal blocks derived from polar vinyl monomers and internal blocks derived from conjugated dienes and optionally monovinyl aromatics are two living intermediates that were originally synthesized. It is understood that it cannot be produced by coupling diblock or triblock copolymers. This is because active lithium atoms are always bonded to poly (polar vinyl monomer) blocks, which for practical reasons are composed of poly (conjugated dienes) and / or poly (monovinyl aromatic) blocks. This is because it can be produced only in the final step after the end capping agent is introduced into the growing chain.
[0008]
Furthermore, those skilled in the art will recognize that symmetric linear block copolymers comprising end blocks derived from polar vinyl monomers and internal blocks derived from conjugated dienes and optionally monovinyl aromatic hydrocarbons use monofunctional lithium initiators, It is understood that it cannot be produced by subsequent polymerization of each monomer.
[0009]
[Problems to be Solved by the Invention]
One of the objects of the present invention in view of the still existing need for linear symmetric block copolymers that can meet the modern requirements of elaborate end use and therefore must exhibit significantly improved physical properties. It will be appreciated that is to provide the linear symmetric block copolymer, and another object was to provide a method for making the block copolymer.
[0010]
[Means for Solving the Problems]
As a result of further research and experimentation, it was surprisingly found that these symmetric block copolymers have the desired narrow molecular weight distribution (Mw / Mn ≦ 1.20, preferably ≦ 1.10).
[0011]
Thus, the present invention provides a compound of the formula C-A-B-A-C or C-B-C (where B block represents a poly (mainly conjugated diene) block, optionally optionally hydrogenated). The vinyl content of the precursor copolymer is 20-45 mol% with respect to the initially present conjugated diene, the A block represents a poly (mainly monovinyl aromatic) block, and the C block is a poly (mainly polar vinyl). Compound) represents a block and represents a bound weight fraction of ≦ 30% by weight, preferably ≦ 15% by weight, more preferably 3 to 9% by weight, based on the weight of the total block copolymer, and all linear blocks The molecular weight distribution of the copolymer is ≦ 1.20, preferably ≦ 1.10).
[0012]
Preferably, the B block of the symmetrical linear block copolymer of formula CA-B-AC or CBC is selectively hydrogenated until the residual unsaturation (RU) is ≦ 20%, preferably ≦ 5%. .
[0013]
When the previously defined linear symmetric block copolymer is selectively hydrogenated, the tensile strength, the permanent set at break, the modulus at 300% elongation, and the temperature behavior (temperature behavior) ) Compared to the corresponding properties of symmetrical linear block copolymers comprising poly (mainly conjugated diene) blocks, non-terminal poly (mainly polar vinyl monomer) blocks and optionally poly (mainly monovinyl aromatic) blocks , Found surprisingly improved.
[0014]
As used throughout this specification, “poly (mainly conjugated dienes), poly (mainly polar vinyl monomers) and poly (mainly monovinyl aromatic) blocks” means that the indicated monomers are substantially pure, or A small amount of structurally related monomers (eg, isoprene with butadiene or vice versa), or a small amount of structurally different monomers, preferably mixed with the same comonomer or monomers that occur in other block segments (Ie, in an amount of less than 15 mol%, preferably less than 5 mol% of the total monomers of the block).
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Suitable examples of the monomer mixture constituting block B include isoprene or butadiene and any small amount of styrene, α-methylstyrene, p-vinyltoluene, m-vinyltoluene, o-vinyltoluene, 4-ethylstyrene, 3 Ethyl styrene, 2-ethyl styrene, 4-t-butyl styrene, 2,4-dimethyl styrene, butadiene or isoprene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene and 1 , 3-pentadiene or mixtures thereof with monomers selected from mixtures thereof.
[0016]
Suitable examples of the monomer mixture constituting the optional block A include styrene and an arbitrarily small amount of α-methylstyrene, p-vinyltoluene, m-vinyltoluene, o-vinyltoluene, 4-ethylstyrene, 3-ethyl. Styrene, 2-ethylstyrene, 4-t-butylstyrene, 2,4-dimethylstyrene, 2 or 4-vinylpyridine, butadiene, isoprene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1, Mention may be made of mixtures with monomers selected from the group consisting of 3-butadiene and 1,3-pentadiene or mixtures thereof.
[0017]
Preferably, the monomer constituting block A is a mixture of a majority of styrene and a small amount of structurally related monomers as defined above, preferably α-methylstyrene, while the monomer constituting block B is Selected from butadiene, isoprene and mixtures thereof.
[0018]
Suitable examples of monomer mixtures constituting block C include lower alkyl (C ₁ -C ₄ ) esters of acrylic acid or methacrylic acid (eg t-butyl methacrylate, methyl acrylate, methyl methacrylate, etc.) or maleic acid, Esters or anhydrides of fumaric acid, itaconic acid, cis-4-cyclohexane-1,2-dicarboxylic acid, endocis-bicyclo (2,2,1) -5-heptene-2,3-dicarboxylic acid or mixtures thereof; Mention may be made of mixtures of principal components selected from 2- or 4-vinylpyridine.
[0019]
In particular, the invention relates to linearly symmetric block copolymers that are selectively hydrogenated, wherein each block is derived from a substantially pure single monomer.
[0020]
More preferably, selectively hydrogenated poly (butadiene) or poly (isoprene) block, poly (styrene) block and / or poly (acrylate) or poly (methacrylate) block having hydrolyzable ester groups. It is a block copolymer having.
[0021]
Most preferred are block copolymers having selectively hydrogenated poly (butadiene) blocks, poly (styrene) blocks and / or poly (t-butyl acrylate) blocks or poly (t-butyl methacrylate) blocks. The block copolymer exhibits a tensile strength (greater than 30 MPa) that is 30% greater than conventional thermoplastic elastomers ABA. The temperature behavior of the novel block copolymers is also improved compared to conventional ABA based polymers. The use temperature of a C-A-B-A-C block copolymer in which the content of a polar vinyl monomer selected from methyl acrylate, methyl methacrylate, t-butyl acrylate and t-butyl methacrylate is about 8% by weight is the conventional A -Increased to 20-30 degrees above the B-A triblock copolymer.
[0022]
It was found that the permanent set at break of A-B-A was improved in C-A-B-A-C block copolymers with short PMMA blocks (reduced from 25% to less than 20%). It was found that the modulus at 300% elongation increased to 10 MPa.
[0023]
The apparent molecular weight of suitable poly (mainly polar vinyl monomer) blocks of these symmetrical linear block copolymers is 3000 to 180,000, whereas the molecular weight of all block copolymers is 80,000 to 180,000. 5000, preferably 3500-5500.
[0024]
Another feature of the present invention is that the symmetrical linear block copolymer C-A-B-A-C or C-B-C (B block is selectively hydrogenated and hydrolyzable group as defined above). C blocks derived from acrylates or methacrylates, preferably tert-butyl acrylate or tert-butyl methacrylate, are completely or partially hydrolyzed).
[0025]
In particular, the hydrolyzed C-A-B-A-C block copolymer (block C is hydrolyzed to more than 10% of the amount of ester groups initially present) has improved mechanical properties. It was found to have properties. For example, the tensile strength is significantly increased at relatively low acid content and decreases with further increase in acid content.
[0026]
As can be seen, the significantly improved physical properties defined above are prior art documents disclosing block copolymers and are described in European patent application no. 0564,910 A2, 0480,336 A2, 0486,335 A2 and British patent no. Monofunctional lithium initiators as described in US Pat. No. 1,332,165 are used, or European patent application no. 0298667A2, 0599671A2 and US Pat. Discloses at least one poly (polar vinyl monomer) block made by using a bifunctional lithium initiator, such as disclosed in US Pat. No. 4,104,331, which cannot provide the required narrow molecular weight distribution. According to the prior literature, the person skilled in the art could not have foreseen.
[0027]
It will be appreciated that another aspect of the present invention is formed by the immediately preceding non-hydrogenated intermediate block copolymer having the characteristic microstructure defined above.
[0028]
Another aspect of the present invention is formed by a process for the production of a linear symmetric block copolymer as defined above. The method
(A) at a temperature in the range of -20 to 60 ° C, in an apolar hydrocarbon main solvent, optionally in the presence of a tertiary amine, 2 equivalents of monoorganolithium initiator, Reacting with isopropenylbenzene;
(B) an ether activator in an amount of at most 10% by volume, preferably ≦ 8% by volume, based on the total solvent volume, optionally mixed with C1-C15 alkoxy lithium or lithium ether alkoxide, and as defined above Charging primarily the conjugated diene monomer into the dilithioinitiator solution of step (a) to essentially complete the polymerization;
(C) after the introduction of the end-capping reagent and the addition of the ether activator, charging primarily monovinyl aromatic monomers or mainly polar vinyl monomers to essentially complete the polymerization;
(D) optionally introducing an end-capping reagent and an ether activator and charging mainly polar vinyl monomers to essentially complete the polymerization;
(E) optionally, after termination of the living block copolymer, optionally hydrogenating the poly (conjugated diene) midblock of the resulting block copolymer;
(F) and optionally hydrolyzing the terminal poly (polar vinyl monomer) block.
[0029]
As will be appreciated by those skilled in the art, the steps (a), (b), (c) and (d) are preferably carried out under an inert gas atmosphere, preferably under nitrogen gas.
[0030]
Examples of ethers that can be used in reaction steps (b), (c) and (d) include diethyl ether, dibutyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, ethylene glycol diethyl ether, diethylene glycol dibutyl ether. 1,2-diethoxypropane, dioxane, triethylene glycol ether, 1,2-dimethoxybenzene, 1,2,3-trimethoxybenzene, 1,2,4-trimethoxybenzene, 1,2,3- Examples include triethoxybenzene, 1,2,3-tributoxybenzene, 1,2,4-triethoxybenzene, or a mixture thereof. Preferred ethers are dioxane, 1,2-diethoxypropane, diethyl ether and tetrahydrofuran.
[0031]
As the mono-organolithium initiator used in the step (a), various kinds of aryl, aralkyl, cycloalkyl or alkyllithium compounds can be used. More preferably, a lower alkyl lithium initiator is used, and most preferably t-butyl lithium or sec-butyl lithium is used.
[0032]
It has been found that the main solvent of the apolar hydrocarbon is preferably selected from cycloalkanes having 5 to 8 carbon atoms, more preferably 5 or 6. It is also possible to use a mixture of the cycloalkane or a predominant amount of the cycloalkane and a small amount of a C5-8 aliphatic hydrocarbon, although the use of substantially pure cyclopentane is most preferred. I understood that.
[0033]
The alkoxylithium compound optionally used in step (a) preferably has 3 to 6 carbon atoms, most preferably 4 carbon atoms. Most preferably t-butoxy lithium is used.
[0034]
The alkoxy lithium or lithium ether alkoxide compound is added at a concentration of 0 to 5 molar equivalents relative to 1 equivalent of lithium already present.
[0035]
Suitable lithium ether alkoxides optionally used in step (b) are those of the general formula R ¹ (OR ² ) _m Li (R ¹ is a linear or branched lower alkyl group having 1 to 6 carbon atoms, an arylalkyl group or Represents an alkylaryl group, R ² represents a linear or branched alkylene group having 2 to 4 carbon atoms, and m is 1, 2 or 3. Preferably, the lithium ether alkoxide is selected from methoxyethoxylithium ethanolate or methoxylithium ethanolate.
[0036]
The amount of ether activator used in the reactor medium of steps (b), (c) and (d) is at most 10% by volume, preferably ≦ 8% by volume.
[0037]
The tertiary amine used optionally is used in a molar ratio of 0.1 to 10, preferably 0.5 to 2, with respect to butyllithium.
[0038]
As will be appreciated, according to a preferred method embodiment, the primary solvents of steps (a), (b), (c), (d), (e) and (f) are one and the same. This is not strictly necessary.
[0039]
The optional hydrogenation step (e) can be carried out by methods known per se, which are usually used for the selective hydrogenation of common ABA polymers, such as described in European patent no. 018910, 031682, 0358382, 068419, 041897 and 0467429, and European patent application no. 0301,665,0471,415,0460,725,0532,099 and 0549,063.
[0040]
According to a preferred embodiment, the living polymer obtained in step (d) is terminated with hydrogen or an isotope thereof and immediately hydrogenated with a titanium di (cyclopentadienyl) catalyst.
[0041]
The optional hydrolysis of the poly (methacrylate ester) or poly (acrylate ester) block can be performed by methods well known in the art, preferably at a temperature of 130-150 °, under an inert gas, preferably under nitrogen. In the presence of a catalytic amount of strong sulfonic acid such as methanesulfonic acid or p-toluenesulfonic acid at a concentration of 1 to 3% by weight relative to the weight of the polymer. Hydrolysis to a residual ester content of ≦ 10 mol% was found not to affect the central block structure.
[0042]
The present invention is illustrated by the following examples, but the scope of the invention is not limited to these specific embodiments.
[0043]
【Example】
Example 1
Reaction of BuLi with 1,3-diisopropenylbenzene To a stirred vessel containing 200 ml of dehydrated cyclohexane, 0.68 g (6 mmol) of triethylamine was added. 6 mmol of t-butyllithium (t-BuLi) (1.2 ml of hexane solution 5 ml) and 0.48 g (3 mmol) of 1,3-diisopropenylbenzene were then added at 0 ° C. When the reaction was continued for 1 hour, 1,3-bis (1-lithio, 1-methyl-3,3-dimethylbutyl) benzene was obtained.
[0044]
Example 2
Synthesis of high vinyl SBS block copolymer with 1,3-bis (1-lithio, 1-methyl-3,3-dimethylbutyl) benzene A reactor charged with 1 l of dehydrated cyclohexane was charged with a few drops of 1,3-bis. (1-Lithio, 1-methyl-3,3-dimethylbutyl) benzene was added and the solution was titrated. The reactor was then charged at room temperature with 7.5 g of diethyl ether and then 36 g of butadiene and 40 ml of Example 1 solution containing 0.6 mmol of diinitiator. The temperature was raised to 40 ° C. and the polymerization was continued at 40 ° C. for 10 hours.
[0045]
Taking a sample for analysis showed that polybutadiene exhibited the following characteristics: Peak Mw: 65000 g / mol, Mw / Mn = 1.06, vinyl content: 44%
19 g of styrene was then added to the reactor and polymerization was continued at 40 ° C. for 2 hours. Polymerization was stopped by adding 1 ml of methanol to the solution. Stabilization of the recovered triblock copolymer showed the following characteristics. Peak Mw: 100,000 g / mol, Mw / Mn = 1.07. When the sample was subjected to ozonolysis, PS remained with a peak Mw of 18000 g / mol.
[0046]
The tensile strength of the solvent cast sample was 31.5 MPa, the elongation at break was 1000%, the modulus of 300% elongation was 4.9 MPa, and the permanent strain was 25%.
[0047]
Examples 3-5
Synthesis of high vinyl SBS block copolymer with 1,3-bis (1-lithio, 1-methyl-3,3-dimethylbutyl) benzene Other similar SBS triblock copolymers were synthesized according to Example 2, but diethyl ether was Replaced with THF, t-butyl methyl ether and DEP. The characteristics of the block copolymer are shown in Table I.
[0048]
[Table 1]

[0049]
Examples 6-8
Synthesis of PMMA-SBS-PMMA Block Copolymer A solution of living Li-SBS-Li triblock copolymer was synthesized using the method of Example 2. After completion of styrene polymerization, 12 ml of a 0.5 molar cyclohexane solution of diphenylethylene was added. The end capping reaction was continued for 30 minutes at room temperature. The red solution was then cooled to 0 ° C., 1 l of dehydrated tetrahydrofuran was added, and the solution was cooled to −78 ° C. When 4.8 g of methyl methacrylate was introduced at this temperature, a colorless and transparent solution was obtained. The polymerization was continued for 30 minutes, and 1 ml of methanol was introduced to terminate the polymerization. Stabilization of the recovered polymer with an antioxidant showed the characteristics shown in Table II.
[0050]
[Table 2]

[0051]
Examples 9-12
Synthesis of PTBMA-SBS-PTBMA Block Copolymers These block copolymers were synthesized in the same manner as described in Examples 6-8 except that MMA was replaced with TBMA (t-butyl methacrylate). The characteristics of these block copolymers are shown in Table III.
[0052]
[Table 3]

[0053]
Examples 13-16
Synthesis of Hydrogenated PMMA-SBS-PMMA Block Copolymer and Hydrogenated PTBMA-SBS-PTBMA Block Copolymer Solution of Living Li-PMMA-SBS-PMMA-Li Block Copolymer obtained according to Examples 6-8 and Example 9 The resulting living Li-PTBMA-SBS-PTBMA-Li block copolymer solution was treated with methanol and hydrogen gas, respectively, and the stopped block copolymer solution was then treated with aluminum / cobalt, aluminum / nickel and titanium dicyclopentadienyl. Several commonly known hydrogenation catalysts selected from were used to substantially hydrogenate (RU ≦ 5%). The characteristics of the resulting block copolymer are shown in Table IV and compared to structurally related commercial block copolymer grades.
[0054]
[Table 4]

[0055]
^a KRATON G-1654 ™, a block copolymer grade comprising poly (styrene) -poly (ethylene-butylene) -polystyrene block copolymer, wherein the poly (ethylene-butylene) block has an ethylenic residual unsaturation of less than 1% It is.

Claims (2)

formula:
C-A-B-A-C or C-B-C
[Wherein, the A block represents a poly (mainly monovinyl aromatic) block, the B block represents a selectively hydrogenated poly (mainly conjugated diene) block, and the C block represents a poly (mainly polar vinyl compound). ) Represents the block and the C block represents a bound weight fraction of ≦ 30% by weight relative to the weight of the total block copolymer. ]
In the symmetric linear block copolymer represented by
The vinyl content of the B block precursor copolymer is in the range of 20-45 mol% with respect to the initially present conjugated diene, and the molecular weight distribution of the total linear block copolymer is ≦ 1.20. The symmetric linear block copolymer. A process for producing a symmetric linear block copolymer according to claim 1 ,
(A) 2 equivalents of monoorganolithium initiator in 1,3-diisopropenylbenzene in a non-polar hydrocarbon main solvent, optionally in the presence of a tertiary amine, at a temperature in the range of -20 to 60 ° C. Reacting with:
(B) an ether activator optionally mixed with an alkoxylithium having 1 to 15 carbon atoms or a lithium ether alkoxide in an amount of at most 10 % by volume relative to the total solvent volume, and a conjugated diene monomer as defined above, filling the dilithioinitiator solution of a) to essentially complete the polymerization;
(C) after the introduction of the end-capping reagent and the addition of the ether activator, charging primarily monovinyl aromatic monomers or mainly polar vinyl monomers to essentially complete the polymerization;
(D) optionally introducing an end-capping reagent and an ether activator and charging mainly polar vinyl monomers to essentially complete the polymerization;
(E) selectively hydrogenating the poly (conjugated diene) intermediate block of the resulting block copolymer after termination of the living block copolymer;
(F) and optionally a step comprising hydrolyzing the terminal poly (polar vinyl monomer) block.