JP2000053734A - Block copolymer and its molding product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a block copolymer capable of exhibiting high hardness, excellent elastomer characteristics and heat stability by including a polystyrene, a polyisoprene and a poly-2-vinylpyridine as constituent block components. SOLUTION: This block copolymer has a chemical structure of the formula A-B-C [one or more polymer blocks of A to C are rigid blocks composed of an addition block of a monomer consisting essentially of at least one monomer selected from a styrene-based monomer, a (meth)acrylate-based monomer and a conjugated diene-based monomer or its hydrogenated substance and the residual polymer blocks are non-rigid blocks composed of an addition block of a monomer consisting essentially of at least one monomer selected from a (meth) acrylate-based monomer and a conjugated diene or its hydrogenated substance] in a molecular main chain and is capable of forming a three-phase mutually continuous microphase separation structure in an molecule aggregate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention has a wide range of uses as a thermoplastic elastomer because it has thermoplasticity, is excellent in thermal stability, and can exhibit excellent elastomer properties even when it has high hardness. The present invention relates to a novel block copolymer usable for: Also, the present invention
The present invention relates to an elastomeric material and a molded product comprising the block copolymer.

[0002]

2. Description of the Related Art Thermoplastic elastomers are widely used as elastomeric materials having ease of molding, such as automotive parts, electronic / electric equipment parts, and construction / civil engineering applications. In particular, a styrene-based thermoplastic elastomer represented by an ABA type block copolymer, such as a polystyrene-polybutadiene-polystyrene block copolymer and a polystyrene-hydrogenated polybutadiene-polystyrene block copolymer, has a hard block ( By appropriately selecting the conditions such as the content and the molecular weight of the polystyrene block, elastomer properties such as stress-strain properties can be improved. Komatsu Koei, "Thermoplastic Elastomers: Basics, Applications, Markets, and Future Prospects" (1995)
Published by Nikkan Kogyo Shimbun on October 30, 2008). The ABA type block copolymer corresponding to the above-mentioned styrene-based thermoplastic elastomer has a structure in which the microphase-separated structure in the molecular aggregate is spherical to columnar as the content of the polystyrene block, which is a hard block, is increased. Since it changes into a lamellar structure through the structure, although the hardness is increased, it has resinous properties and does not have excellent elastomer properties. Accordingly, it is difficult for this type of ABA block copolymer to achieve both high hardness and excellent elastomer properties.

[0003] As for the relationship between the polymer block composition and the microphase-separated structure in the block copolymer as described above, block copolymers other than ABA type have been studied. In an ABC type block copolymer containing polyisoprene and poly-2-vinylpyridine as constituent block components, specifically, in a microphase-separated structure, a three-phase bicontinuous structure is formed between a columnar structure and a lamellar structure. It has been reported that it appears stably in a relatively wide composition range (for example, Macromol
ecules, 1994, Vol. 27, No. 6755-6
760 page). However, even with the same ABC-type block copolymer, it has been reported that a three-phase co-continuous structure is formed with a triblock component of polystyrene, polybutadiene and polymethyl methacrylate. No (for example, Macromolec
ules 1995, Vol. 28, Nos. 3080-309
See page 7).

[0004]

The present inventors have conducted various studies on ABC type block copolymers comprising the above-mentioned polystyrene, polyisoprene and poly-2-vinylpyridine as constituent block components. Depending on the composition ratio, it is possible to exhibit excellent elastomer properties even when having a high hardness, and,
It has been found that this property is derived from the fact that a three-phase bicontinuous structure is specifically formed even in a composition region where the content of the hard block (polystyrene block and poly2-vinylpyridine block) is relatively high. Was. However, it has also been found that this type of block copolymer is inferior in thermal stability and has great restrictions on practical applications. Thus, an object of the present invention is to provide a novel thermoplastic polymer which can exhibit excellent elastomer properties even when having a high hardness, and also has excellent thermal stability, and An object of the present invention is to provide an elastomeric material and a molded product exhibiting excellent properties.

[0005]

As a result of repeated studies, the present inventors have found that the above-mentioned object can be achieved in a specific ABC-type block copolymer and complete the present invention. Reached.

[0006] That is, according to the present invention, one of the above-mentioned problems is represented by the following expression:

[0007]

Embedded image ABC (I)

(Wherein, A, B and C each represent a polymer block having a mutually different chemical structure, provided that one or two polymer blocks of A, B and C are An addition polymer of a monomer mainly composed of at least one monomer selected from the group consisting of a styrene-based monomer, a (meth) acrylate-based monomer and a conjugated diene-based monomer; A hard block composed of an additive, and wherein the remaining two or one polymer block is at least one selected from the group consisting of a (meth) acrylate monomer and a conjugated diene monomer. It is a soft block composed of an addition polymer of a monomer mainly composed of a kind of monomer or a hydrogenated product thereof.)

Having the chemical structure shown in the molecular main chain,
It is also achieved by providing a block copolymer capable of forming a three-phase bicontinuous microphase-separated structure in a molecular assembly.

According to the present invention, one of the other problems is that the block copolymer comprises a chemical structure represented by the above formula (I) in the molecular main chain, and the block copolymer is a terpolymer. This is achieved by providing an elastomeric material forming a phase co-continuous microphase separated structure.

Further, according to the present invention, the above-mentioned still another object is attained by providing a molded article at least partially composed of the above-mentioned elastomeric material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The block copolymer of the present invention contains three kinds of polymer blocks A, B and C having different chemical structures in a molecular main chain, and a three-dimensional polymer in a molecular assembly. It can form a phase-co-continuous microphase separation structure. However, one or two polymer blocks of A, B and C are at least one selected from the group consisting of styrene monomers, (meth) acrylate monomers and conjugated diene monomers. Is a hard block composed of an addition polymer of a monomer mainly composed of the above-mentioned monomer or a hydrogenated product thereof. Further, the remaining polymer blocks of A, B and C are at least one selected from the group consisting of (meth) acrylate monomers and conjugated diene monomers.
It is a soft block composed of an addition polymer of a monomer mainly composed of a kind of monomer or a hydrogenated product thereof. In addition,
In the present specification, the “(meth) acrylate-based monomer” is a general term for an acrylate-based monomer and a methacrylate-based monomer.

The hard block in the block copolymer of the present invention may have a substantially single glass transition point in a temperature range exceeding 20 ° C., since the tensile strength of the block copolymer is particularly good. More preferably, it has a substantially single glass transition point in a temperature range of 40 ° C. or higher. For the purpose of forming a hard block having such a glass transition point, styrene, α-methylstyrene, vinyltoluene, p-ter
Styrene monomers such as t-butylstyrene; methyl methacrylate, ethyl methacrylate, propyl methacrylate, sec-butyl methacrylate, ter methacrylate
Monomers of at least one of (meth) acrylate monomers such as t-butyl, glycidyl methacrylate, trifluoromethyl methacrylate, and tert-butyl acrylate; and conjugated diene monomers such as cyclohexadiene It is preferred to use the body. The hard block may be a homopolymer block formed by addition polymerization of one type of monomer or a copolymer block formed by addition polymerization of two or more types of monomers, These polymer blocks may be hydrogenated blocks obtained by partially or completely hydrogenating unsaturated portions. Examples of the polymer constituting the hard block include styrene-based polymers such as polystyrene, poly α-methylstyrene, polyvinyltoluene, and poly p-tert-butylstyrene; polymethyl methacrylate, polyethyl methacrylate, and polymethacrylic acid. Propyl, polysec-butyl methacrylate, tert-butyl polymethacrylate,
(Meth) acrylate polymers such as polyglycidyl methacrylate, trifluoromethyl methacrylate, and tert-butyl polyacrylate (in the present specification,
“(Meth) acrylate polymer” is a general term for acrylate polymers and methacrylate polymers); and conjugated diene polymers such as polycyclohexadiene and hydrogenated polycyclohexadiene.

The soft block in the block copolymer of the present invention has a particularly good elastomer characteristic such as a return after stress release in the block copolymer, so that the soft block is substantially in a temperature range of 20 ° C. or less. It preferably has a single glass transition point, and more preferably has a substantially single glass transition point in a temperature range of 10 ° C. or lower.
For the purpose of forming a soft block having such a glass transition point, mainly, hexyl methacrylate, octyl methacrylate, decyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate,
Ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylic acid sec
-Use of at least one monomer among (meth) acrylate monomers such as butyl, heptyl acrylate, 3-pentyl acrylate, and hexyl acrylate; and conjugated diene monomers such as butadiene and isoprene Is preferred. The soft block may be a homopolymer block formed by addition polymerization of one type of monomer, or a copolymer block formed by addition polymerization of two or more types of monomers, These polymer blocks may be hydrogenated blocks obtained by partially or completely hydrogenating unsaturated portions. Examples of the polymer constituting the soft block, polyhexyl methacrylate,
Poly (octyl methacrylate), poly (decyl methacrylate),
Polylauryl methacrylate, polyethyl methacrylate 2-ethylhexyl, polyethyl acrylate, polypropyl acrylate, polyisopropyl acrylate, n-butyl polyacrylate, sec-butyl polyacrylate, heptyl polyacrylate, polyacrylic acid 3 (Meth) acrylate polymers such as pentyl and polyhexyl acrylate; and conjugated diene polymers such as polybutadiene, polyisoprene, hydrogenated polybutadiene and hydrogenated polyisoprene.

In the block copolymer of the present invention,
One of each of the polymer blocks A, B and C is a hard block and the remaining two are soft blocks, or two of each of the polymer blocks A, B and C are It is a hard block, and the remaining one is a soft block. To this extent, the polymer blocks of A, B and C may each be a hard block or a soft block, and the arrangement order of the hard block and the soft block is not particularly limited. However, it is preferable that each of the A block and the C block is a hard block, and the B block is a soft block, in that the properties as the thermoplastic elastomer are particularly easily exhibited. Incidentally, the block copolymer of the present invention,
It is not limited to the triblock copolymer.

Among the combinations of the polymer blocks in the block copolymer of the present invention, the following are preferable representative examples composed of (hard block)-(soft block)-(hard block). it can.

(Polystyrene)-(polybutadiene)-
(Polymethyl methacrylate); (polystyrene)-
(Polyisoprene)-(polymethyl methacrylate);
(Polystyrene)-(Hydrogenated polybutadiene)-
(Polymethyl methacrylate); (polystyrene)-
(Hydrogenated product of polyisoprene)-(polymethyl methacrylate); (polystyrene)-(polylauryl methacrylate)-(polymethyl methacrylate); (polystyrene)-(poly (2-ethylhexyl methacrylate)-(polymethacrylic acid) (Methyl); (polystyrene)-(n-butyl polyacrylate)-(polymethyl methacrylate);
(Poly (methyl methacrylate))-(poly (lauryl methacrylate)-(poly (trifluoromethyl methacrylate))

In the block copolymer of the present invention, the A block, the B block and the C block each form a microphase-separated phase in the aggregate of the molecules, and the phase separation structure is a three-phase bicontinuous structure. It is necessary to have certain properties. Here, such a three-phase co-continuous microphase-separated structure is formed by cutting out a part of an aggregate of block copolymers produced by a method such as cooling after melt-kneading, solvent removal of a solution, and the like. By cutting each in two or more directions at an angle to each other, 20
Two or more types of thin sections having a thickness in the range of about 100 nm to about 100 nm are prepared, and each is observed by means of a direct transmission electron microscope (hereinafter abbreviated as TEM) or the like.
TDD (ordered-tricontinuous-
double-diamond) structure (for example, Mac
romolecules, 1994, Vol. 27, No. 6
755-6760) and the like, and confirm that the structure is the same as the three-phase bicontinuous structure. Prior to observation of the slice, the desired phase may be selectively stained with an electronic staining reagent such as osmium tetroxide or ruthenium tetroxide, if necessary. When preparing a sample for confirming the presence or absence of the property of forming a three-phase co-continuous structure, it is preferable to employ a manufacturing condition that allows the block copolymer to easily form a three-phase co-continuous structure in an aggregated state. preferable. For example, when the sample is prepared by removing the solvent from the block polymer solution, the polymer solution is prepared using a solvent that does not significantly differ in the solubility of each of the blocks A, B, and C. Is preferred. When the sample is prepared by melting and cooling the block polymer, the block copolymer is melt-kneaded for a sufficient time while applying a sufficient shearing force, and then the temperature of each part of the polymer in the aggregated state is minimized. It is preferable to cool and solidify under uniform conditions.

The number average molecular weight of the block copolymer of the present invention is not necessarily limited, but is preferably in the range of 20,000 to 1,000,000. In the block copolymer of the present invention, the molecular weight distribution represented by the ratio of (weight average molecular weight) / (number average molecular weight) is preferably in the range of 1.0 to 1.5. The number average molecular weight of each block in the block copolymer of the present invention is not necessarily limited as long as the microphase-separated structure of the aggregate of the block copolymer can be a three-phase bicontinuous structure. , A
Under the condition that the block is in the range of 1000 to 300,000, the block B is in the range of 8000 to 900,000, and the block C is in the range of 1000 to 300,000,
It is preferable that the block copolymer has a number average molecular weight capable of forming a three-phase bicontinuous structure. Further, the block copolymer of the present invention may have a functional group such as a hydroxyl group, a carboxylic acid group, an amino group, or an epoxy group at the terminal or side chain of the molecular main chain.

The block copolymer of the present invention is not necessarily limited. For example, the block copolymer of the present invention may be hydrogenated by performing a stepwise addition polymerization reaction of a predetermined monomer in accordance with a known anionic polymerization method. The polymer can be produced by sequentially forming a predetermined polymer block including each of the unreacted A, B and C blocks in an arbitrary order, and further performing a hydrogenation reaction as necessary. Note that whether or not the block copolymer can form a three-phase bicontinuous structure depends on conditions such as the type of monomer constituting each block and the relative ratio of the number average molecular weight of each block. In producing the block copolymer of the present invention, it is preferable to appropriately select these conditions based on preliminary experiments and the like.

In the above addition polymerization reaction, conditions usually used in anionic polymerization can be adopted. Usually, the polymerization temperature is in the range of -100 ° C to + 100 ° C, and the polymerization time is in the range of 0.01 to 200 hours. The polymerization atmosphere is preferably under an inert gas such as dry argon or nitrogen. As the polymerization initiator in the above-described anionic polymerization, an initiator capable of normally performing anionic polymerization of a monomer to be used can be appropriately selected and used. Examples of the initiator include alkali metals such as sodium metal and lithium metal; and organic alkali metal compounds such as methyl lithium, ethyl lithium, n-butyl lithium and sec-butyl lithium. In the above-described anionic polymerization, a solvent that can be used in ordinary anionic polymerization can be appropriately selected and used, but in a series of polymerization for forming each block that is not hydrogenated, a predetermined hard block is used. In order to form a soft block, a solvent exchange is carried out during the polymerization according to an ordinary method, or an additive or a solvent is added, as necessary, so that a predetermined monomer can be subjected to addition polymerization with a predetermined regularity. May be performed. As the solvent in the above-described anionic polymerization, a solvent which can normally perform anionic polymerization of the monomer to be used can be appropriately selected and used. As the solvent, for example, hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, benzene, and toluene; ether solvents such as diethyl ether, anisole, tetrahydrofuran, and tetrahydropyran can be used alone or in combination.

Certain types of block copolymers of the present invention can be produced by the above-mentioned addition polymerization reaction, while other types of the block copolymers obtained by the addition polymerization reaction include: Further, it is produced by subjecting a carbon-carbon unsaturated double bond contained therein to a hydrogenation reaction. The hydrogenation reaction can be carried out according to a known method, for example, by catalytic hydrogenation in the presence of a hydrogenation catalyst in a solvent. As the solvent, a solvent inert to the hydrogenation reaction, such as hexane or cyclohexane, is preferably used. As the catalyst, for example, Raney nickel or Pt, Pd, R
a heterogeneous catalyst such as a supported catalyst in which a metal such as u, Rh, and Ni is supported on a carrier such as carbon, alumina, and diatomaceous earth; or a transition metal compound and an organoaluminum compound;
A Ziegler-based catalyst or the like composed of a combination with an organic lithium compound or the like is used. Other conditions in the hydrogenation reaction are not necessarily limited,
The hydrogen pressure is usually in the range of normal pressure to 200 kg / cm ² , the reaction temperature is usually in the range of normal temperature to 250 ° C., and the reaction time is usually in the range of 0.1 to 200 hours.

The method for isolating the block copolymer from the reaction mixture after the above addition polymerization or hydrogenation is not necessarily limited. For example, the reaction mixture containing the block copolymer may be isolated from methanol or the like. The block copolymer of the present invention can be obtained by coagulating by contact with a poor solvent, taking out the coagulated product, pre-drying, and then drying under heating or reduced pressure.

Since the block copolymer of the present invention has thermoplasticity, it can be subjected to various molding methods such as injection molding and extrusion molding, and can be formed into various shapes such as sheet, hose, box and ball. It can be molded into molded articles. As described above, in the block copolymer of the present invention, each of the blocks A, B, and C forms a microphase-separated phase in its molecular assembly, and the phase-separated structure has a three-phase bicontinuous structure. By subjecting the block copolymer to thermal molding, a molded article composed of an elastomeric material having a three-phase bicontinuous microphase-separated structure is produced. be able to. Although not necessarily limited, in order to uniformly develop such a three-phase bicontinuous structure in the elastomeric material and the molded article, at the time of their production, the block copolymer is sufficiently melt-kneaded or sufficiently kneaded. Good results can be obtained by adopting molding conditions that give a high shear force, or by cooling and solidifying a polymer in a molten state in an aggregated state under conditions that make the temperature of each part uniform. easy.

In the elastomeric material of the present invention, it is necessary that the A block, the B block and the C block each form a microphase-separated phase, and that the phase-separated structure has a three-phase bicontinuous structure. . Further, the molded article of the present invention only needs to have at least a part thereof composed of the elastomeric material having the three-phase continuous structure. The molded article of the present invention includes a molded article of the elastomeric material alone. Products, as well as composites (laminates, 2
Color molded articles) are also included. In addition, these three-phase co-continuous microphase-separated structures are obtained by cutting a sample cut out from a portion made of an elastomeric material or a block copolymer of a molded article in two or more directions at an angle to each other. Two or more types of slices having a thickness in the range of about 100 nm can be prepared and determined by observing each of them in the same manner as described above.

The elastomeric material of the present invention and the portion of the elastomeric material in the molded article of the present invention are often
Having a JIS A hardness in the range of 65 to 95,
The tensile test shows elongation in the range of 500% to 1000% and elongation in the range of 10% to 80%. Here, the elongation is defined as the distance between two chucks holding a sample in a tensile test, before the test and one hour after the end of the test. The value calculated by [(distance between chucks after 1 hour of test) × 100 / (distance between chucks before test)] × 100 / (elongation (%)) (Unit:%).

Since the elastomeric material and molded article of the present invention have excellent thermal stability and excellent elastomer properties even with high hardness, they are used for automobile parts, sporting goods, light electric equipment parts, electric cables, civil engineering parts. It is particularly advantageously used as a building material. Further, the block copolymer of the present invention can also be used as a modifier for a synthetic resin.

[0028]

The present invention will be specifically described below with reference to examples.
Note that the present invention is not limited by these examples. In the following Examples and Comparative Examples, as the solvent and the monomer, those sufficiently distilled under a nitrogen gas stream were used in the same manner as in the case of the usual anionic polymerization.

Example 1 (Production example of triblock copolymer of (polystyrene)-(polyisoprene)-(polymethyl methacrylate)) In a 1-liter autoclave purged with nitrogen, 230 g of methylcyclohexane and sec-butyllithium were placed. After charging 0.092 g (hereinafter abbreviated as s-BuLi), 17.3 g of styrene was added and addition polymerization was performed at 40 ° C. for 3 hours. Thereafter, a part of the polymer was sampled and analyzed. The analysis was carried out by gel permeation chromatography in terms of polystyrene (hereinafter abbreviated as GPC), and the number average molecular weight (hereinafter abbreviated as Mn) and the ratio of weight average molecular weight / number average molecular weight (hereinafter Mw / M).
n). As a result, Mn = 1200
0, it was found that polystyrene with Mw / Mn = 1.09 was formed. After the above polymerization, 34.6 g of isoprene
Was dropped into the system, and addition polymerization was performed at 40 ° C. for 3 hours. Thereafter, a part of the obtained polymer was sampled and analyzed. In the analysis, Mn and Mw / Mn were measured by GPC, and the weight ratio of polystyrene / polyisoprene was determined by nuclear magnetic resonance absorption measurement (hereinafter abbreviated as NMR). As a result, Mn = 48700, Mw / Mn =
It was found that the weight ratio of polystyrene / polyisoprene was 1/2. 0.55 g of 1,1-diphenylethylene was added to the obtained polymerization reaction system, and 4
After maintaining at 0 ° C. for 1 hour, the mixture was cooled to −78 ° C., and 267 g of tetrahydrofuran was slowly added dropwise. After completion of the dropwise addition of tetrahydrofuran, stirring was further continued for 3 hours, and then 17.3 g of methyl methacrylate was added to the system.
Addition polymerization was performed at 78 ° C for 3 hours. Thereafter, 0.5 g of methanol was added into the system to terminate the polymerization. When the polymerization is stopped, a part of the obtained polymer is sampled and subjected to GPC.
And NMR, Mn = 61200, Mw
/Mn=1.05, polystyrene / polyisoprene / polymethyl methacrylate (weight ratio) = 1/2/1 (polystyrene)-(polyisoprene)-(polymethyl methacrylate) triblock copolymer is final It was able to confirm that it was obtained. The polymerized solution thus obtained was poured into 8000 g of methanol to coagulate the polymer, and the coagulated product was recovered.
By performing the reaction for 0 hour, the triblock copolymer 6
9.2 g were obtained. Next, the glass transition point (hereinafter abbreviated as Tg) of each polymer block was measured. The polymer sample was vacuum-dried at 60 ° C for 20 hours and then subjected to compression molding at 220 ° C. Using the obtained test piece, 10 ° C. in a temperature range of −150 ° C. to + 250 ° C.
Differential scanning calorimetry was performed at a heating rate of / min. that time,
When a change in specific heat due to the glass transition of the polymer block in the polymer was observed, the temperature was determined as the Tg of the polymer block. As a result, the Tg of the polyisoprene block was -70 ° C, and the Tg of the polystyrene block was 9
At 5 ° C., the Tg of the polymethyl methacrylate block is 11
Observed at 0 ° C.

Comparative Example 1 (Production Example of Triblock Copolymer of (Polystyrene)-(Polyisoprene)-(Polystyrene)) In a 1-liter autoclave purged with nitrogen, 460 g of cyclohexane and 0.092 g of s-BuLi were charged. Thereafter, 17.3 g of styrene was added, and addition polymerization was performed at 40 ° C. for 3 hours. Thereafter, a part of the obtained polymer was sampled and analyzed. The analysis was performed by GPC in terms of polystyrene, and Mn and Mw / Mn were determined. As a result, it was found that polystyrene having Mn = 12000 and Mw / Mn = 1.10 was formed. After the above polymerization, 34.6 g of isoprene was dropped into the system,
Time addition polymerization was performed. Thereafter, a part of the obtained polymer was sampled and analyzed. Analysis was performed by GPC
n and Mw / Mn were measured, and the weight ratio of polyisoprene block / polystyrene block (hereinafter abbreviated as PIp / PSt) was determined by NMR. As a result, Mn = 48700, Mw / Mn = 1.08, PIp
It was found that / PSt = 2/1. 17.3 g of styrene was added to the obtained polymerization reaction system, and addition polymerization was performed at 40 ° C. for 3 hours. Thereafter, 0.5 g of methanol was added into the system to terminate the polymerization. When the polymerization was stopped, a part of the obtained polymer was sampled and analyzed by GPC and NMR. As a result, Mn = 60700, Mw / Mn = 1.0
6. It was confirmed that a triblock copolymer of (polystyrene)-(polyisoprene)-(polystyrene) having PIp / PSt = 1/1 was finally obtained. The thus obtained solution after polymerization is poured into 8000 g of methanol to coagulate the polymer, the coagulated product is recovered, and vacuum drying is performed at 30 ° C. for 20 hours to obtain the triblock copolymer. 69.2 g were obtained.

Comparative Example 2 (Production Example of Triblock Copolymer of (Polystyrene)-(Polyisoprene)-(Poly-2-vinylpyridine)) 530 g of tetrahydrofuran was charged into a 1-liter autoclave purged with nitrogen and charged at -78 ° C. After cooling to
After charging 0.037 g of s-BuLi, styrene 7.
0 g was added and addition polymerization was carried out for 1 hour. Thereafter, a part of the obtained polymer was sampled and analyzed. The analysis was performed by GPC, and Mn and Mw / Mn were determined. As a result, it was found that polystyrene having Mn = 12000 and Mw / Mn = 1.05 was formed. After the above polymerization, 14.0 g of isoprene was dropped into the system, and the mixture was added at -78 ° C for 4 hours.
The addition polymerization was performed for 8 hours. Thereafter, a part of the obtained polymer was sampled and analyzed. In the analysis, Mn and Mw / Mn were measured by GPC, and P
Ip / PSt was determined. Mn = 48500, Mw / Mn
= 1.10, PIp / PSt = 2/1. 2-vinylpyridine 7.0 was added to the obtained polymerization reaction system.
g was added and addition polymerization was carried out at -78 ° C for 10 hours. Thereafter, 0.5 g of methanol was added into the system to terminate the polymerization. When the polymerization was stopped, a part of the obtained polymer was sampled and analyzed by GPC. As a result, Mn = 60600, M
w / Mn = 1.09, and from NMR, the weight ratio of polystyrene / polyisoprene / poly2-vinylpyridine is 1/2/1 (polystyrene)-(polyisoprene)-(poly2-vinylpyridine) It was confirmed that the triblock copolymer was finally obtained. The polymerized solution thus obtained was poured into 2500 g of methanol to coagulate the polymer, the coagulated product was recovered, and vacuum drying was performed at 30 ° C. for 20 hours to obtain the triblock copolymer 28. 0.0 g was obtained.

Evaluation Test Examples The block copolymers obtained in the above Examples and Comparative Examples were subjected to the following various observation and measurement tests.

(1) TEM observation Each block copolymer was dried at 40 ° C. for 20 hours, compression-molded at 220 ° C. with a press die having a uniform thickness, and then cooled together with the press die by cooling press. 20 ° C so that the temperature of each part of the block copolymer in the mold becomes uniform
The sample was cooled to a sheet thickness of 1 mm. About 2mm from near the center of the surface of this sheet sample
Four-sided square areas were cut out, and the cut pieces were cut in two directions so that the cut surfaces formed an angle of 90 degrees with each other, to produce two types of ultrathin pieces having a thickness of about 50 nm.
These two ultrathin sections were stained overnight in osmium tetroxide vapor. For each of the two dyed samples prepared as described above, the microphase-separated structure of the polymer block phase was observed by TEM.

(2) Tensile test A sheet-like sample produced by compression molding in the same manner as described above was used to perform a JIS standard vulcanized rubber physical test method (JIS).
No. 3 type dumbbell described in K6301) was punched out. Using this dumbbell, pulling speed 500mm / mi
A tensile test was performed under the conditions of n, and tensile strength and elongation were measured. Further, the state of the sample after the test (the presence or absence of a change such as whitening) was visually confirmed. Furthermore, the distance between the two chucks to which the dumbbell-shaped sample was fixed was measured before the test (the measured value is represented by “L0”). After the test, the fractured sample piece was allowed to stand at 20 ° C. for 1 hour. The distance between the chucks was measured in a state where the fractured surfaces were closely joined (the measured value is represented by “L1”), and based on these measured values, the elongation (%) = [(L1 / L0) × 100 / (elongation (%))]
× 100 was determined.

(3) Hardness Measurement A sheet-like sample produced by compression molding in the same manner as above was stacked so as to have a thickness of 12 mm, and the hardness was measured using a JIS A type hardness meter.

(4) Measurement of Thermal Stability A sheet sample produced by compression molding in the same manner as above was dried at 60 ° C. for 10 hours. Using this sample, under a nitrogen stream, 10 ° C./m from 30 ° C. to 500 ° C.
The thermogravimetric loss measurement was carried out at a heating rate of "in" to determine a 5% weight loss temperature.

The results of the various observation or measurement tests are shown in Table 1 below.

[0038]

[Table 1]

From the above Table 1, the block copolymer of the present invention obtained in Example 1 was compared with the block copolymer of Comparative Example 1 in which a three-phase co-continuous microphase-separated structure was not formed. Although it has the same high hardness, the sample state after the tensile test has no change such as whitening and the return is good (that is, the value of the "elongation percentage" after the tensile test is small). As can be seen, it has remarkably excellent elastomer properties. In addition, it can be seen that the block copolymer of the present invention of Example 1 has excellent thermal stability as compared with the block copolymer of Comparative Example 2 which is different from the present invention in the constituent monomer components.

[0040]

The block copolymer of the present invention has thermoplasticity, excellent thermal stability, and can exhibit excellent elastomer properties even at high hardness. It can be used for a wide range of applications as an elastomeric material.

Claims (3)

[Claims] 1. Formula: ABC (wherein A, B and C each represent a polymer block having a different chemical structure from each other, provided that A, B
And one or two polymer blocks of C are
An addition polymer of a monomer mainly composed of at least one monomer selected from the group consisting of a styrene-based monomer, a (meth) acrylate-based monomer and a conjugated diene-based monomer; A hard block composed of an additive, and wherein the remaining two or one polymer block is at least one selected from the group consisting of a (meth) acrylate monomer and a conjugated diene monomer.
It is a soft block composed of an addition polymer of a monomer mainly composed of a kind of monomer or a hydrogenated product thereof. A block copolymer having the chemical structure represented by the formula (1) in the molecular main chain, and capable of forming a three-phase bicontinuous microphase-separated structure in a molecular assembly. 2. Formula ABC (wherein A, B and C each represent a polymer block having a mutually different chemical structure, provided that A, B
And one or two polymer blocks of C are
An addition polymer of a monomer mainly composed of at least one monomer selected from the group consisting of a styrene-based monomer, a (meth) acrylate-based monomer and a conjugated diene-based monomer; A hard block composed of an additive, and wherein the remaining two or one polymer block is at least one selected from the group consisting of a (meth) acrylate monomer and a conjugated diene monomer.
It is a soft block composed of an addition polymer of a monomer mainly composed of a kind of monomer or a hydrogenated product thereof. An elastomeric material comprising a block copolymer having the chemical structure represented by the formula (I) in the molecular main chain, wherein the block copolymer forms a three-phase bicontinuous microphase-separated structure. 3. A molded article at least partially composed of the elastomeric material according to claim 2.