JP2005336434A - Block copolymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugate diene for producing a molding wherein anisotropy occurs but little in strength degradation during a process of high-shear molding such as injection molding and for fabricating a film or a sheet wherein balance is excellent between the strengths and transparency. <P>SOLUTION: This block copolymer comprising the vinyl aromatic hydrocarbon and the conjugate diene has 2-3 kinds of hard segment block sections mainly comprising the vinyl aromatic hydrocarbon but different in molecular weight from each other, with the molecular weight distribution (Mw/Mn) falling in the 2-6 range. Furthermore, a thermoplastic resin composition is prepared by adding a styrene resin to the block copolymer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diene, in which a plurality of microdomain structures appear aperiodically and is extremely excellent in impact resistance, and the block copolymer is made into another transparent styrene resin. It is a resin composition excellent in transparency and impact resistance obtained by blending with. Further, the composition is useful as a modifier for various thermoplastic resins.

A block copolymer consisting of a vinyl aromatic hydrocarbon and a conjugated diene, and having a relatively high vinyl aromatic hydrocarbon content, uses its properties such as transparency and impact resistance, and is suitable for injection molding applications, sheets, Widely used in extrusion molding applications such as films.
A block copolymer and a styrenic polymer composition blended with the block copolymer have excellent characteristics such as transparency or impact resistance, but several proposals have been made to obtain desired physical properties. For example, two types of linear copolymers composed of vinyl aromatic hydrocarbons and conjugated dienes, and copolymers obtained by coupling them, the number average molecular weights of the high molecular weight component and the low molecular weight component of the vinyl-substituted aromatic hydrocarbon block There are branched block copolymers having a ratio of 3 to 7 and a production method thereof (for example, see Patent Document 1). In addition to this, a branched block copolymer having a polymer block having three or more vinyl aromatic hydrocarbons as monomer units and a production method thereof (for example, see Patent Document 2) are known.

  Furthermore, a linear copolymer composition having a molecular weight distribution of the vinyl aromatic hydrocarbon block part of 2.3 to 4.5, or a molecular weight distribution of the vinyl aromatic hydrocarbon block part of 2.8 to 3.5. And a branched block copolymer composition produced by blending (see, for example, Patent Document 3) and a branch having a molecular weight distribution of the vinyl aromatic hydrocarbon block portion outside the range of 2.8 to 3.5. A method of combining a block copolymer (for example, see Patent Document 4), a branched block copolymer having a plurality of periodic microdomain structures (for example, see Non-Patent Document 5), and the like are known. Yes.

JP-A-53-000286 Japanese Patent Laid-Open No. 07-173232 JP-A-52-0778260 JP-A-57-028150 Journal of Applied Polymer Science, Vol. 85,701-713 (2002)

  However, in these methods, the block copolymer and the composition obtained by mixing it with other thermoplastic resins have a poor balance between transparency and impact resistance. In addition, in the injection molding in which the molding is performed under high shear, there is a problem that anisotropy is easily generated in the obtained molded product, and the strength is weakened on the other hand. In addition, the block copolymer as described in Non-Patent Document 5 has a problem that the elongation and the like of the molded product are excellent, but the impact resistance is inferior.

  In view of the present situation, the present inventors have excellent balance of transparency and impact resistance in injection molded products as well as extrusion molded products and blow molded products, and are particularly excellent in impact resistance as well as elongation of molded products. As a result of various studies to obtain a block copolymer composition, it is composed of a hard segment block portion mainly composed of vinyl aromatic hydrocarbons and a soft segment block portion mainly composed of conjugated dienes, and has a plurality of microdomain structures. It has been found that a block copolymer in which is aperiodically exhibited is extremely excellent in impact resistance. In addition, the block copolymer of the present invention is blended with a styrenic resin such as another block copolymer, so that it is resistant to deterioration in transparency not only in extrusion molded products and blow molded products but also in injection molded products. It was found that the impact property was greatly improved, and the present invention was made.

  That is, the present invention comprises a vinyl aromatic hydrocarbon and a conjugated diene, and is composed of a hard segment block portion composed of a block portion mainly composed of vinyl aromatic hydrocarbons and a soft segment block portion composed of a block portion mainly composed of conjugated diene. The present invention relates to a block copolymer characterized in that a plurality of microdomain structures appear aperiodically and a thermoplastic resin composition using the block copolymer.

  The block copolymer obtained by the present invention has a characteristic of extremely excellent impact resistance. Moreover, the thermoplastic resin composition excellent in transparency and impact resistance can be obtained by blending the block copolymer of the present invention with a styrenic resin such as another block copolymer. In addition, the resin composition can be used in a wide variety of molding processes such as extrusion molding, blow molding, injection molding, etc., and in any case, a molded product with a very good balance between transparency and impact resistance can be obtained. Can do.

Hereinafter, the present invention will be described in detail.
Examples of the vinyl aromatic hydrocarbon used in the block copolymer of the present invention include styrene, o-methylstyrene, p-methylstyrene, p-tertbutylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene. , Vinyl anthracene and the like, and styrene is a particularly common one. You may use not only these 1 type but 2 or more types of mixtures.
The conjugated diene is a diolefin having a pair of conjugated double bonds having 4 to 8 carbon atoms, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2 1,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like, and particularly common ones include 1,3-butadiene and isoprene. You may use not only these 1 type but 2 or more types of mixtures.

  The block copolymer of the present invention must have a plurality of microdomain structures. Thereby, the block copolymer can express extremely high impact resistance. Whether or not there are a plurality of microdomain structures can be determined by observing an ultrathin section of a block copolymer stained with osmic acid with a transmission electron microscope (TEM). Since the soft segment block portion has a higher proportion of the conjugated diene structure stained with osmic acid than the hard segment block portion, the soft segment block portion is observed as a deeply stained image in a transmission electron micrograph. . Block copolymers consisting of vinyl aromatic hydrocarbons and conjugated dienes as monomer units generally result in the hard segment block portion and soft segment block portion repelling each other, resulting in a single microscopic structure such as a sphere, cylinder, bicontinuous, and lamella. It is known to form a domain structure periodically. Here, a plurality of microdomain structures exist non-periodically, and two microdomain structures such as a sphere, a cylinder, a co-continuous, and a lamella coexist and coexist in a field of view of at least 8 μm × 6 μm. The two microdomain structures are not a periodic structure such as the branched block copolymer described in Journal of Applied Polymer Science, Vol. 85,701-713 (2002), but exist aperiodically. Refers to being. As a sample for transmission electron microscope observation, a block copolymer composed of vinyl aromatic hydrocarbon and conjugated diene is cast from toluene, which is generally known as a good solvent, and then annealed. The film obtained in this way is used.

In order for a plurality of microdomain structures to appear non-periodically in the block copolymer, it is essential to satisfy the following i) to iii) simultaneously. That is,
i) It consists of 35 to 95% by mass of vinyl aromatic hydrocarbon and 5 to 65% by mass of conjugated diene as monomer units.
ii) There are 2 to 3 types of hard segment block portions having different molecular weights.
iii) Molecular weight distribution (Mw / Mn) is in the range of 2-6.
It is essential.

When the block copolymer consists of more than 95% by weight of vinyl aromatic hydrocarbon and less than 5% by weight of conjugated diene as monomer units, the microdomain structure itself does not appear and the impact resistance of the block copolymer It becomes inferior in property and is not preferable. On the other hand, when the block copolymer is composed of less than 35% by weight of vinyl aromatic hydrocarbon and 65% by weight of conjugated diene as monomer units, the block copolymer only has a single microdomain structure and is processed. Inferior properties and rigidity are also undesirable.
In the block copolymer, when the vinyl aromatic hydrocarbon monomer unit is 45% by mass or more and 85% by mass or less based on the total mass of the block copolymer, a plurality of aperiodic microdomain structures appear and a viewpoint of balance of physical properties. And more preferably 50% by mass or more and 80% by mass or less. Similarly, when the conjugated diene monomer unit is more than 15% by mass and less than 55% by mass based on the total mass of the block copolymer, a plurality of aperiodic microdomain structures appear, which is preferable from the viewpoint of physical property balance. Furthermore, it is even more preferable if it is more than 20% by mass and less than 50% by mass.

  In addition, as its structure, it is essential to comprise a hard segment block part mainly composed of vinyl aromatic hydrocarbons and a soft segment block part mainly composed of conjugated dienes, but the hard segment part of the block copolymer is composed of vinyl. An aromatic hydrocarbon homopolymer or a copolymer block having a taper structure or random structure made of vinyl aromatic hydrocarbon and conjugated diene may be used. Similarly, the soft segment block portion may be a conjugated diene homopolymer or a copolymer block having a tapered structure or a random structure composed of a conjugated diene and a vinyl aromatic hydrocarbon.

  Further, the block copolymer has 2-3 hard segment block portions having different molecular weights, and the molecular weight distribution (Mw / Mn) is in the range of 2-6. If the hard segment block part is one kind, not only a plurality of non-periodic microdomain structures will appear, but it is not preferable because it is inferior in impact resistance, and it has four or more kinds of block parts from the viewpoint of impact resistance. It is not preferable. When the hard segment block portion having a different molecular weight has 2 to 3 types of block portions, a plurality of microdomain structures appear, which is more preferable from the viewpoint of impact resistance. Two types of hard segment block parts having different molecular weights are more preferable from the viewpoint of impact resistance. When the molecular weight distribution (Mw / Mn) of the block copolymer is in the range of 2 to 6, a plurality of microdomain structures appear, but the molecular weight distribution (Mw / Mn) of the block copolymer is less than 2. Has a plurality of microdomain structures and is inferior in impact resistance, and if it is 6 or more, it is extremely inferior in moldability. When the molecular weight distribution (Mw / Mn) of the block copolymer is in the range of 2.5 to 5, a plurality of microdomain structures appear, and the balance of impact resistance and molding processability is preferable. The molecular weight of the block copolymer The distribution (Mw / Mn) is more preferably 2.8 to 5. In order to sort out the hard segment block part, it is described in Polymer, vol 22, 1721 (1981), Rubber Chemistry and Technology, vol. 59, 16 (1986) or Macromolecules, vol. 16, 1925 (1983). As described above, the block copolymer may be obtained by ozonolysis and then reducing it with lithium aluminum hydride to obtain a polymer component, or by sampling the polymerization solution immediately after the polymerization of the polymer block is completed. The latter method is preferably employed.

  When two sets of the hard segment block parts of the block copolymer are S1 and S2, and the number average molecular weights of S1 and S2 are M1 and M2, respectively, M1 is 80000 or more, 160000 or less, 90000 or more, It is more preferable that it is 140000 or less from the surface of impact strength and molding processability. M2 is 4000 or more and 10,000 or less, and 5000 or more and 9000 or less are more preferable in terms of impact strength and molding processability.

  Furthermore, M1 / M2 is 13 or more and 22 or less, preferably 14 or more and 19 or less. When M1 / M2 is within this range, the block copolymer has a good balance of impact strength, rigidity and molding processability.

  In the block copolymer, S1 / S2 (molar ratio) representing the ratio of S1 and S2 is 5/95 or more and 30/70 or less, preferably 10/90 or more and 25/75 or less. Within this range, impact resistance, rigidity, transparency, and molding processability are good.

  The molecular weight of the block copolymer is not particularly limited, but examples of a preferable molecular weight range from the viewpoint of impact resistance, rigidity, and molding processability are 60000 to 110000 as the number average molecular weight and 100000 to 18000 as the weight average molecular weight. . More preferably, the number average molecular weight is 80000 to 90000, and the weight average molecular weight is 120,000 to 150,000. The molecular weight distribution is not particularly limited, but a preferable molecular weight distribution range from the viewpoint of impact resistance and molding processability is 1.3 to 2.0, more preferably 1.4 to 1.8. Become.

Next, a particularly preferable structure of the block copolymer is exemplified as follows. First, a mixture of block copolymers represented by the following general formula (1) having a block part mainly composed of two kinds of vinyl aromatic hydrocarbons having different molecular weights and produced by a coupling reaction can be mentioned. .

S1-B1, S2-B1 and (S1-B1) iX- (B1-S2) m General formula (1)
(A) (b) (c)
(In the formula, S1 and S2 represent a hard segment block part mainly composed of vinyl aromatic hydrocarbon, B1 represents a soft segment block part mainly composed of conjugated diene, and X represents a coupling agent after coupling. I and m are integers of 0 or more, i + m is 1 or more and 8 or less, and if i + m is 1 or more and 8 or less, transparency, impact resistance and molding processability Is preferable because a good block copolymer can be obtained, and more preferably 1 or more and 5 or less.

  The block copolymer contains 65 to 90% by mass of a branched block copolymer in which i = 1 or more and m = 1 or more in the component (c) in the general formula (1). The content of the particularly preferred branched block copolymer is 70% by mass or more and 85% by mass or less. If it is in the range of less than 65% by mass, the impact resistance and molding processability of the block copolymer may be inferior, and it is not preferable, and if it is in the range of more than 90% by mass, the impact resistance may be inferior.

The content of the branched block copolymer in the block copolymer can be determined as follows using a gel permeation chromatogram.
First, linear block copolymers S 1 -B 1 and S 2 -B 1 prior to coupling are obtained, and the sum s 1 of the areas of the respective peaks corresponding to the linear reaction after the coupling reaction is obtained. Next, in the block copolymer, s / s0, which is a ratio of the difference s (s = s0−s1) obtained by subtracting s1 from the total peak area s0 after the coupling reaction and the total peak area s0, is expressed in percentage. The content of the branched block copolymer can be determined.

  The block copolymer of the present invention is a block copolymer produced by a coupling reaction. The block copolymer is obtained by a normal living anion polymerization method using an organolithium compound as an initiator in a hydrocarbon solvent. Here, vinyl aromatic hydrocarbon and conjugated diene are used as monomers, and a coupling agent is added after anionic polymerization is performed using an organic lithium compound as an initiator in a hydrocarbon solvent to generate a living active terminal. Then, it is synthesized through a coupling reaction in which a living active terminal is reacted with a coupling agent. That is, the coupling reaction means that a polymer chain having a living active site at one end is bound and bound. A coupling agent is a compound having two or more reaction sites per molecule that a living active site can attack.

  As the coupling agent, a bifunctional coupling agent having two reaction sites per molecule may be used, or a polyfunctional coupling agent having three or more reaction sites per molecule may be used. Moreover, a polyfunctional coupling agent may be used individually by 1 type, and 2 or more types of polyfunctional coupling agents may be used together, and also 1 or more types of bifunctional coupling agent and 1 or more types may be used. The polyfunctional coupling agent can be used in combination. Preferably, a polyfunctional coupling agent is used alone.

When performing a coupling reaction, the reaction site which the living active site in a coupling agent can attack does not necessarily need to react completely, and one part may remain without reacting. Furthermore, it is not necessary that the polymer chain having all living active sites at one end reacts with the reaction site of the coupling agent, and the polymer chain remaining without reacting may remain.
Therefore, the block copolymer when using a polyfunctional coupling agent has a branch number equal to the number of branches expected when the reaction site of the used coupling agent has completely reacted, and the coupling used. The reaction site of the agent has fewer branches than expected when fully reacted, the living active site is simply replaced with a coupling agent, and the reaction site of the coupling agent does not react Any two or more of the remaining items are mixed.

  Coupling agents include chlorosilane compounds such as silicon tetrachloride and 1,2-bis (methyldichlorosilyl) ethane, alkoxysilane compounds such as tetramethoxysilane and tetraphenoxysilane, tin tetrachloride, and polyhalogenated hydrocarbons. , Carboxylic acid esters, polyvinyl compounds, epoxidized oils and fats such as epoxidized soybean oil and epoxidized linseed oil.

  Among such coupling agents, examples of the bifunctional coupling agent having two reaction sites per molecule include dimethyldichlorosilane and dimethyldimethoxysilane. On the other hand, examples of the polyfunctional coupling agent having three or more reaction sites per molecule include methyltrichlorosilane, methyltrimethoxysilane, tetrachlorosilane, tetramethoxysilane, and tetraphenoxysilane. Epoxidized oils and fats also have a polyfunctional coupling agent because they have three ester-bonded carbonyl carbons per molecule and have at least one epoxy group on the long-chain alkyl group side.

The coupling agent preferably used in the present invention is a polyfunctional coupling agent, among which epoxidized fats and oils are preferable. Epoxidized oils and fats include epoxidized soybean oil and epoxidized linseed oil, among which epoxidized soybean oil is particularly preferred.
Epoxidized fats such as epoxidized soybean oil and epoxidized linseed oil are compounds obtained by epoxidizing a glycerin ester of a long-chain carboxylic acid mixture containing an unsaturated acid such as oleic acid, linoleic acid, and linolenic acid. Therefore, when these are used as a polyfunctional coupling agent, the number of branches of the block copolymer expected when the reaction site is completely reacted is 3 epoxy groups and 1 carbonyl group per 1 linolenic acid residue. However, one oleic acid residue has one epoxy group and one carbonyl group, and one linoleic acid residue has two epoxy groups and one carbonyl group. A block copolymer having 5 or 3 branches or 4 can be formed. That is, when the reaction site is completely reacted, a block copolymer mixture having 3 to 5 branches is obtained, that is, the block copolymer has a maximum of 5 branches.

  A thermoplastic resin composition characterized by containing a block copolymer and a thermoplastic resin other than these is excellent in impact resistance strength, transparency, and moldability. Specifically, a thermoplastic resin obtained by blending block copolymer A shown below with block copolymer in a range of block copolymer / block copolymer A = 20 to 80/80 to 20 (mass ratio). The composition has an excellent balance of physical properties such as impact resistance, transparency and molding processability.

The block copolymer A is characterized by satisfying the following a) to f) at the same time.
A) As a monomer unit, it comprises 55 to 95% by mass of vinyl aromatic hydrocarbon and 5 to 45% by mass of conjugated diene.
B) Its structure consists of a hard segment block part mainly composed of vinyl aromatic hydrocarbons and a soft segment block part mainly composed of conjugated dienes.
C) The hard segment block portion has two block portions having different molecular weights represented by S3 and S4.
D) When the number average molecular weights M3 and M4 of S3 and S4 are set, M3 is in the range of 75000 to 170000 and M4 is in the range of 14000 to 30000.
E) The ratio M3 / M4 of M3 and M4 is in the range of 4-9.
F) The ratio of S3 and S4 is in the range of S3 / S4 = 6 to 35/65 to 94 (molar ratio).

  When the block copolymer / block copolymer A is 20 to 80/80 to 20 (mass ratio), the balance of molding processability, impact resistance, and transparency is further improved as compared with the block copolymer alone. When the mixing ratio of the block copolymer is less than 20 and the block copolymer A exceeds 80, the impact strength of the finally obtained thermoplastic resin composition becomes inferior, and the mixing of the block copolymer When the ratio is more than 80 and the block copolymer A is less than 20, the resulting thermoplastic resin composition has low transparency.

  The block copolymer A is characterized by comprising 55 to 95% by weight of vinyl aromatic hydrocarbon and 5 to 45% by weight of conjugated diene as monomer units based on the total weight of the block copolymer A. When the vinyl aromatic unit price hydrogen is 45% by weight or more and 85% by weight or less as a monomer unit and the conjugated diene is more than 15% by weight and less than 55% by weight, the physical property balance is further improved. When the unit is vinyl aromatic aromatic unit hydrogen of 50% by mass or more and 80% by mass or less and the conjugated diene is more than 20% by mass and less than 50% by mass, the physical property balance is further improved.

When the respective number average molecular weights M3 and M4 of S3 and S4 are used, it is preferable that M3 is in the range of 75000 to 170000 and M4 is in the range of 14000 to 30000, and if M3 is less than 75000, the finally obtained thermoplasticity The impact resistance of the resin composition is inferior, and if it exceeds 170000, the transparency is lowered. When the M4 is less than 14,000, the transparency and impact resistance of the thermoplastic resin composition are inferior, and when it exceeds 30000, the impact resistance is lowered.
M3 is preferably 100,000 or more and 150,000 or less, and M4 is particularly preferably 15000 or more and 18000 or less from the viewpoint of the balance of moldability, transparency and impact resistance of the thermoplastic resin composition finally obtained.

The ratio M3 / M4 of M3 and M4 of the block copolymer A is preferably in the range of 4-9.
When M3 / M4 is less than 4, the thermoplastic resin composition finally obtained is inferior in molding processability and impact resistance, and when the ratio M3 / M4 exceeds 9, the finally obtained thermoplastic resin composition The transparency of things is inferior. As a particularly preferred range, the ratio of M3 / M4 is 5-8.

  As a ratio (molar ratio) of S3 and S4 of the block copolymer A, a range of S3 / S4 = 6 to 35/65 to 94 is preferable. As a result, the thermoplastic resin composition finally obtained has a good balance of moldability, transparency and impact resistance. When the ratio of S3 is 6 or less, that is, when S4 exceeds 94, the impact resistance and the transparency are inferior. A particularly preferable ratio of S3 and S4 includes a range of S3 / S4 = 10-30 / 70-90 (molar ratio).

  The molecular weight of the block copolymer A is not particularly limited, but examples of a preferable molecular weight range from the viewpoint of molding processability include a number average molecular weight of 60000 to 16000 and a weight average molecular weight of 90000 to 220,000. More preferably, the number average molecular weight is 80,000 to 140,000, and the weight average molecular weight is 120,000 to 200,000. Further, the molecular weight distribution of the block copolymer A is not particularly limited, but a preferable molecular weight distribution range from the viewpoint of molding processability of the block copolymer is 1.2 to 1.8, more preferably 1. 3 to 1.6.

Block copolymer A is a block copolymer represented by the following general formula (2) as a block copolymer produced by a coupling reaction having a block part mainly composed of two kinds of vinyl aromatic hydrocarbons having different molecular weights. Examples thereof include a mixture of copolymers.
S3-B2, S4-B2 and (S3-B2) nY- (B2-S4) o General formula (2)
(D) (e) (f)

(Wherein S3 and S4 represent a hard segment block part mainly composed of vinyl aromatic hydrocarbons, B2 represents a soft segment block part mainly composed of conjugated diene, and Y represents a coupling agent after the coupling reaction) N, o represents an integer of 0 or more, n + o is from 1 to 8, and when n + o is from 1 to 8, transparency, impact resistance and molding processability are good. A preferable block copolymer can be obtained, and it is more preferably 1 or more and 5 or less.

  The block copolymer A represented by the general formula (2) is a branched block copolymer of i = 1 or more and m = 1 or more among the components (f) in the general formula (2). It is preferable to contain 65-90 mass%. The content of the particularly preferred branched block copolymer is 70% by mass or more and 85% by mass or less. When the content of the branched block copolymer in the block copolymer is in the range of less than 65% by mass, the resulting thermoplastic resin composition may be inferior in impact resistance, transparency and molding processability. If it exceeds 90% by mass, the impact resistance may be inferior.

The content of the branched block copolymer in the block copolymer A can be determined as follows using a gel permeation chromatogram.
First, the linear block copolymers S3-B2 and S4-B2 prior to coupling are obtained, and the sum s2 of the areas of the respective peaks corresponding to the linear reaction after the coupling reaction is obtained. Next, in the block copolymer, sA / s0A, which is the ratio of the difference sA obtained by subtracting s2 from the total peak area s0A after the coupling reaction (sA = s0A-s2) and the total peak area s0A, is expressed as a percentage. The content of the branched block copolymer can be determined.

The block copolymer and the block copolymer A in the present invention are obtained by a normal living anion polymerization method using an organolithium compound as an initiator in a hydrocarbon solvent.
The basic production method uses a vinyl aromatic hydrocarbon and a conjugated diene as monomers, and after anionic polymerization using an organic lithium compound as an initiator in a hydrocarbon solvent to generate a living active terminal, It is produced by a coupling method in which a living agent is reacted with a coupling agent by adding a coupling agent. For example, a block copolymer and a block copolymer A comprising a block portion containing a vinyl aromatic hydrocarbon monomer as a hard segment block portion and a block portion containing a conjugated diene monomer as a soft segment block portion are produced. When an aromatic polymer is first anionically polymerized using an initiator, an initiator and a vinyl aromatic hydrocarbon are successively added to the polymerization system, and two types of vinyl having different molecular weights are added. It can be produced by forming a polymer block with aromatic hydrocarbon monomer units, then adding a conjugated diene and finally going through a coupling step.

Examples of the organic solvent used in the production of the block copolymer and the block copolymer A include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane, cyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane. Well-known organic solvents such as alicyclic hydrocarbons such as ethylcyclohexane or aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene can be used.
An organic lithium compound is a compound in which one or more lithium atoms are bonded in the molecule, such as ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, t-butyl lithium and the like. Can be used.

  In the production of the block copolymer and block copolymer A, a small amount of a polar compound may be dissolved in a solvent. Polar compounds are used as randomizing agents to improve the efficiency of the initiator, to adjust the microstructure of the conjugated diene, or when copolymerizing the vinyl aromatic hydrocarbon and the conjugated diene. Polar compounds used in the production of block copolymers include ethers such as tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol dibutyl ether, amines such as triethylamine and tetramethylethylenediamine, thioethers, phosphines, phosphoramides, alkyl benzene sulfones. Acid salts, potassium and sodium alkoxides and the like are mentioned, and a preferred polar compound is tetrahydrofuran.

  The polymerization temperature for producing the block copolymer and block copolymer A is generally -10 ° C to 150 ° C, preferably 40 ° C to 120 ° C. The time required for the polymerization varies depending on the conditions, but is usually within 48 hours, particularly preferably 0.5 to 10 hours. The polymerization atmosphere is preferably replaced with an inert gas such as nitrogen gas. The polymerization pressure is not particularly limited as long as it is carried out within a range of pressure sufficient to maintain the monomer and solvent in the liquid layer within the above polymerization temperature range. Furthermore, care must be taken so that impurities that inactivate the initiator and the living polymer, such as water, oxygen, carbon dioxide, etc., do not enter the polymerization system.

  After completion of the polymerization and coupling reaction, the active block copolymer not related to the coupling reaction is activated by using a substance having active hydrogen such as water, alcohol, carbon dioxide, organic acid, inorganic acid or the like as a polymerization terminator. It is inactivated by adding an amount sufficient to inactivate the ends. In this case, for example, when water or alcohol is used as a polymerization terminator, hydrogen is introduced at the polymer chain end, and when carbon dioxide is used, a carboxyl group is introduced. Therefore, a block copolymer containing a block copolymer component having various functional groups at its terminals can be produced by appropriately selecting a polymerization terminator.

  The addition amount of the coupling agent may be any effective amount, but is preferably set so that the reaction site of the coupling agent is present in a stoichiometric amount or more with respect to the living active terminal. Specifically, it is preferable to set the addition amount of the coupling agent so that 1 to 2 equivalents of reaction sites exist with respect to the number of moles of living active terminals present in the polymerization solution before the coupling step. Since the number of moles of lithium atoms present in the reaction system can be calculated from the charged amount of the organolithium compound that is the initiator, the reaction site of the desired number of equivalents can react by regarding this mole number as the number of moles of the living active terminal. The amount of coupling agent added can be determined so as to be present in the system. Here, the equivalent means the number of reaction sites of the coupling agent added to the reaction system as a multiple of the number of living active terminals.

  The thermoplastic resin composition is obtained by containing a block copolymer, a block copolymer typified by block copolymer A and other thermoplastic resins, but there is no particular limitation on the blending method. For example, when the block copolymer A is blended with the block copolymer, the inactivated solution after each polymerization may be mixed, or each pellet is mixed and melt-kneaded with an extruder. Also good.

  Various additives can be further blended into the block copolymer and the thermoplastic resin composition as necessary. To alleviate deterioration due to heat received during molding, to prevent the molded product from deteriorating in an oxidizing atmosphere or under irradiation with ultraviolet rays, or to provide physical properties suitable for the purpose of use For example, additives such as stabilizers, lubricants, processing aids, antiblocking agents, antistatic agents, antifogging agents, weather resistance improvers, softeners, plasticizers and pigments can be added.

  Examples of the stabilizer include 2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6- Phenolic antioxidants such as di-tert-butyl-4-methylphenol, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, trisnonylphenyl phosphite, bis (2,6 -Di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite Such as down-based antioxidants.

  Examples of lubricants, processing aids, antiblocking agents, antistatic agents, and antifogging agents include saturated fatty acids such as palmitic acid, stearic acid, and behenic acid, fatty acid esters such as octyl palmitate, octyl stearate, and pentaerythritol fatty acid esters, Furthermore, fatty acid amides such as erucic acid amide, oleic acid amide, stearic acid amide, ethylene bis stearic acid amide, glycerin-mono-fatty acid ester, glycerin-di-fatty acid ester, sorbitan-mono-palmitic acid ester, sorbitan -Higher alcohols represented by sorbitan fatty acid esters such as mono-stearic acid ester, myristyl alcohol, cetyl alcohol, stearyl alcohol and the like. White oil and silicone oil can also be added.

  Further, as weather resistance improvers, benzotriazoles such as 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole and 2,4-di-tert-butylphenyl Salicylates such as -3 ', 5'-di-tert-butyl-4'-hydroxybenzoate, benzophenone UV absorbers such as 2-hydroxy-4-n-octoxybenzophenone, and tetrakis (2,2, Examples include hindered amine type weather resistance improvers such as 6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate.

  These additives are preferably used in the block copolymer and the thermoplastic resin composition in the range of 0 to 5% by mass or less.

  The block copolymer and the thermoplastic resin composition thus obtained can be produced by any conventionally known molding method such as extrusion, injection molding, hollow molding, and injection of sheets, foams, films, and various shapes. It can be easily molded into a wide variety of practically useful products such as molded products, hollow molded products, compressed air molded products, vacuum molded products, and biaxially stretched molded products.

A polystyrene resin can be mix | blended with a thermoplastic resin composition as needed.
In addition to the polystyrene resin, a styrene-butyl acrylate copolymer and a styrene-methyl methacrylate copolymer can be suitably used.

  The block copolymer and the polystyrene resin can be arbitrarily blended depending on the purpose. Considering the balance of transparency, rigidity, and moldability, block copolymer / polystyrene resin = 30 / 70-80 / 20, more preferably 40 / 60-70 / 30.

Hereinafter, the present invention will be described with reference to examples. The contents of the present invention are not limited to these examples. By the way, the data shown in Examples and Comparative Examples were measured according to the following method.
The total light transmittance and haze value were measured in accordance with JIS-K7105, Charpy impact strength in accordance with JIS K-7111 (with notch), and test pieces were molded from resin pellets with an injection molding machine.
The drop weight impact strength is obtained by molding a flat plate with a thickness of 2 mm using an injection molding machine, and using a drop weight graphic impact tester (trademark of instrumented drop weight impact tester manufactured by Toyo Seiki Seisakusho). .5 kg of heavyweight is naturally dropped on the plane of the test piece fixed to the holder (diameter 40 mm), and the tester is completely destroyed or penetrated by the striker (diameter 12.7 mm) provided at the lower part of the heavyweight. Energy (referred to as total absorbed energy) was measured.
The amount of polybutadiene rubber component (PBd amount) in the block copolymer was determined by a halogen addition method in which iodine chloride was added to a double bond and measured.
The fluidity (MFR) at high temperature was measured according to JIS K-7210.

The measurement conditions of gel permeation chromatography (GPC) were based on the following measurement conditions 1 and 2.
[Measurement condition 1]
Solvent (mobile phase): THF
Flow rate: 1.0ml / min
Set temperature: 40 ° C
Column configuration: Tosoh TSKguardcolumn MP (XL) 6.0mmID x 4.0cm x 1
And TSK-GEL MULTIPOREHXL-M manufactured by Tosoh Corporation
1.8mmID × 30.0cm (theoretical plate number 16000 steps) 2 and TSK
guardcolumn MP (XL), TSK-GEL MULTIIPOREHXL
-M, TSK-GEL MULTIPOOREHXL-M in total in the order of 3
(32,000 theoretical plates as a whole)
Sample injection volume: 100 μL (sample solution concentration 1 mg / ml)
Supply pressure: 39kg / cm2
Detector: RI detector

[Measurement condition 2]
Solvent (mobile phase): THF
Flow rate: 0.2ml / min
Set temperature: 40 ° C
Column configuration: Showa Denko KF-G 4.6 mm ID x 10 cm x 1 and Showa Denko KF- 404HQ 4.6 mm ID x 25 cm (theoretical plate number 25000) 4 KF-
G, KF-404HQ, KF-404HQ, KF-404HQ, KF
-404 HQ in total (total of 100,000 theoretical plates)
Sample injection volume: 10 μL (sample solution concentration 2 mg / ml)
Supply pressure: 127kg / cm2
Detector: RI detector

Next, the content of the block copolymer and the branched block copolymer contained in the block copolymer A was determined by the method described below using a gel permeation chromatogram. In the case of the block copolymer of the present invention First, with respect to the peaks corresponding to the linear block copolymers S1 -B1 and S2 -B1 prior to coupling, S1 -B1 and S2-obtained from the gel permeation chromatogram of the sample after completion of the third stage butadiene polymerization The peak top molecular weights M5 and M6 of the component corresponding to B1 were measured.
Next, peaks corresponding to M5 and M6 on the gel permeation chromatogram of the block copolymer finally obtained by coupling are unreacted or S1-B1 and S2-B1 to which only a coupling agent has been added. And assigned.

The peak areas of the components corresponding to the assigned S 1 -B 1 and S 2 -B 1 are respectively perpendicular to the valley from the valley between adjacent peaks, and the peak area of the portion surrounded by the base line and the vertical line Calculated as
Next, the sum s1 of the peak areas of the two components is calculated, and the value is subtracted from the area value s0 of the entire chromatogram of the block copolymer, whereby the branched block copolymer weight in the block copolymer is calculated. The combined peak area s (s = s0-s1) was determined. The area ratio s / s0 of the peak area of the branched block copolymer thus determined to the area of the entire chromatogram of the block copolymer is the content of the branched block copolymer in the block copolymer. (Mass%).
The content of the branched block copolymer in the block copolymer A was also determined by the same method as in the case of the block copolymer.
The molar ratio of S1 and S2 in the block copolymer was determined as follows. In the chromatogram by GPC under the measurement condition 1 of the mixture of S1 and S2, the peak top molecular weight values of the peaks corresponding to the components S1 and S2 are Mp1 and Mp2, respectively, and the area ratio of each peak is A1 and A2, respectively. The molar ratio of S1 and S2 was calculated by the following formula.
S1: S2 (molar ratio) = (A1 / Mp1) :( A2 / Mp2)
The molar ratio of S3 and S4 in the block copolymer A was also determined by the same method as in the case of the block copolymer.

Whether or not a plurality of microdomain structures coexist was determined as follows. First, 0.5 g of a block copolymer as a sample was collected and dissolved in 30 g of toluene to prepare a toluene solution having a concentration of 1.7% by mass. This solution was developed in an aluminum petri dish having a diameter of 3.8 cm, and toluene was volatilized at room temperature over 2 days to obtain a cast film (thickness 0.2 mm). Next, this film was annealed at a temperature of 130 ° C. for 12 hours under vacuum, and then rapidly cooled in ice water.
The slice of this film was dye | stained with osmic acid, this was embedded in the epoxy resin, and the epoxy resin was hardened. Subsequently, a block of the cured epoxy resin was cut out so that a part of the section of the embedded film appeared on the cut surface. And this was again dye | stained with osmic acid, Then, the ultrathin section was cut out from the surface where a part of film section appeared further. Using this ultrathin slice, the microdomain structure was observed with a transmission electron microscope.
The black-stained portion is the soft segment block portion, and the white portion is the hard segment block portion. The state of the soft segment block stained black is observed by transmission electron micrographs (magnification 8.9 cm x width 13.3 cm) at magnifications of 99200 and 16800, and two different microdomain structures coexist non-periodically. Judged whether or not.
[Example 1]

First, a block copolymer was synthesized as follows.
A stainless steel polymerization tank with an internal volume of 3 L, equipped with a jacket and a stirrer, was washed with cyclohexane and purged with nitrogen. Under a nitrogen gas atmosphere, 1222 g of cyclohexane dehydrated to a water content of 6 ppm or less containing 150 ppm of tetrahydrofuran was charged into the polymerization tank. 199 g of dehydrated styrene was added to a water content of 5 ppm or less. After raising the internal temperature to 50 ° C., 1.5 ml of a 10% by mass n-butyllithium cyclohexane solution (molar concentration 1.2 mol / l) was added and polymerized for 20 minutes in a range where the maximum temperature did not exceed 120 ° C. ( First stage polymerization).

Next, under a constant internal temperature of 50 ° C., 10.0 ml of a cyclohexane solution of 10% by mass of n-butyllithium was added, and 66 g of styrene dehydrated to a water content of 5 ppm or less was added, and the maximum temperature exceeded 120 ° C. Polymerization was carried out for 20 minutes in the absence (second stage polymerization).
After completion of the second stage polymerization, sampling was performed, and the sampled polymerization solution was diluted with toluene, and this solution was poured into a large amount of methanol to precipitate a polymer component, which was then vacuum dried to obtain a solid content GPC When measurement was carried out under measurement condition 1, there were two types of polystyrene chains in the sampled material, and M1 = 91200 and M2 = 5950 when the number average molecular weights were M1 and M2, respectively, in descending order. The molecular weight distribution was 4.19.

Further, after the temperature was raised to 80 ° C., 163 g of butadiene dehydrated through a molecular sieve was added, and polymerization was performed for 20 minutes within a range where the maximum temperature did not exceed 120 ° C. (third-stage polymerization).
Sampling is performed after completion of the third stage polymerization, and the sampled polymerization solution is diluted with toluene, and the solution is poured into a large amount of methanol to precipitate a polymer component. When the measurement was performed under measurement condition 2, there were two types of polymer chains (styrene-butadiene diblock copolymers having different molecular weights) in the sampled material, and the number average molecular weight (polystyrene equivalent value) was in descending order. When M5 and M6 were used, respectively, M5 = 118500 and M6 = 26650.

After completion of sequential polymerization, a solution in which 1.5 g (equivalent to 1.1 equivalent) of epoxidized soybean oil Vikoflex 7170 (ATOFINA CHEMICALS) was dissolved in 10 ml of cyclohexane was added under a constant internal temperature of 80 ° C., and the cup was added for 30 minutes. A ring reaction was performed (coupling step). Here, a method for determining the amount of epoxidized soybean oil Vikoflex 7170 will be described. Since Vikoflex 7170 has a molecular weight of 1000 and an oxirane oxygen content of 7.1%, Vikoflex 7170 has 4.4 moles of epoxy groups per mole. On the other hand, Vikoflex 7170 has 3 moles of carbonyl groups per mole, so Vikoflex 7170 has 10.4 moles of coupling reaction sites per mole. By the way, from the amount of n-butyllithium added in the first stage polymerization and the second stage polymerization, the lithium atom present in the reaction system is calculated to be 0.0144 mol. Therefore, the mass of Vikoflex 7170 for 1.1 equivalents of the lithium active terminal is
0.0144 (mol) x 1.1 (equivalent) x 1000 / 10.4 = 1.5 g
Is calculated.
Finally, all the polymerization active terminals were deactivated with methanol to obtain a polymerization solution (polymer concentration: 25% by mass).
In addition, sampling is performed after methanol deactivation, and the sampled polymerization solution is diluted with toluene, and a polymer component is precipitated by pouring the solution into a large amount of methanol. Got. The gel permeation chromatogram of the obtained block copolymer was measured under measurement condition 2.

Finally, 0.24-part by mass of 2,4-bis [(octylthio) methyl] -o-cresol as a stabilizer was added to 100 parts by mass of the powdery polymer, It supplied to the single screw extruder, the molten strand was pulled out from the die | dye at 220 degreeC, and it cut with the cutter after water cooling, and obtained pellet-shaped resin. Various charged values are shown in Table 1, various analytical values are shown in Tables 2 to 4, and solid physical property evaluation results are shown in Table 5, respectively. A transmission electron micrograph is shown in FIG. It can be seen from the transmission electron micrograph that two non-periodic microdomain structures coexist.
[Examples 2-9 and Comparative Examples 1-8]

In Examples 2 to 9 and Comparative Examples 1 to 8, a block copolymer was synthesized and pelleted in the same manner as in Example 1 except that the polymerization tanks having the volumes shown in Tables 1 and 13 and the charged amounts of raw materials were used. Got. Various analysis values are shown in Tables 2 to 4 and Tables 14 to 16, and solid physical property evaluation results are shown in Tables 5 and 17. Transmission electron micrographs are shown in FIGS.
[Example 10]

First, block copolymer A was synthesized as follows.
A stainless steel polymerization tank with an inner volume of 3 L, equipped with a jacket and a stirrer, was washed with cyclohexane and purged with nitrogen. Then, in a nitrogen gas atmosphere, 1233 g of cyclohexane dehydrated to a water content of 6 ppm or less containing 150 ppm of tetrahydrofuran was charged into the polymerization tank. 139 g of dehydrated styrene was added to a water content of 5 ppm or less. After raising the internal temperature to 50 ° C., 1.5 ml of a 10% by mass n-butyllithium cyclohexane solution was added and polymerized for 20 minutes within a range where the maximum temperature did not exceed 120 ° C. (first stage polymerization).

Next, under a constant internal temperature of 50 ° C., 7.8 ml of a 10% by mass cyclohexane solution of n-butyllithium was added, followed by 161 g of styrene dehydrated to a water content of 5 ppm or less, and the maximum temperature exceeded 120 ° C. Polymerization was carried out for 20 minutes in the absence (second stage polymerization).
After completion of the second stage polymerization, sampling was performed, and the sampled polymerization solution was diluted with toluene, and this solution was poured into a large amount of methanol to precipitate a polymer component, which was then vacuum dried to obtain a solid content GPC When the measurement was performed under the measurement condition 1, there were two types of polystyrene chains in the sample, and when the number average molecular weights were M3 and M4 in order from the highest, M3 = 95400 and M4 = 15650. .

Further, after raising the internal temperature to 80 ° C., 131 g of butadiene dehydrated by passing through a molecular sieve was added and polymerized for 20 minutes within a range where the maximum temperature did not exceed 120 ° C. (third-stage polymerization).
Sampling is performed after completion of the third stage polymerization, and the sampled polymerization solution is diluted with toluene, and the solution is poured into a large amount of methanol to precipitate a polymer component. When the measurement was performed under measurement condition 2, there were two types of polymer chains (styrene-butadiene diblock copolymers having different molecular weights) in the sampled material, and the number average molecular weight (polystyrene equivalent value) was in descending order. When M7 and M8, respectively, M7 = 119600 and M8 = 36250.
After the completion of sequential polymerization, a solution in which 1.4 g (equivalent to 1.3 equivalents) of epoxidized soybean oil Vikoflex 7170 (ATOFINA CHEMICALS) was dissolved in 10 ml of cyclohexane was added under a constant internal temperature of 80 ° C., and the cup was added for 30 minutes. A ring reaction was performed (coupling step). Finally, all polymerization active terminals were deactivated with methanol to obtain a polymer solution of block copolymer A (polymer concentration 25% by mass).
In addition, sampling is performed after methanol deactivation, and the sampled polymerization solution is diluted with toluene, and the solution is poured into a large amount of methanol to precipitate a polymer component, which is vacuum-dried to solidify the block copolymer A. Got the minute.

Subsequently, 1300 g each of the block copolymer and the block copolymer A obtained in Example 1 were weighed in equal amounts, and both were mixed well. This mixed polymerization solution was diluted with cyclohexane, and this solution was poured into a large amount of methanol to precipitate a polymer component, which was vacuum dried to obtain a powdery polymer.
Finally, 0.24-part by mass of 2,4-bis [(octylthio) methyl] -o-cresol as a stabilizer was added to 100 parts by mass of the powdery polymer, It supplied to the single screw extruder, the molten strand was pulled out from the die | dye at 220 degreeC, and it cut with the cutter after water cooling, and obtained the pellet-shaped thermoplastic resin composition. Various charged values of the block copolymer A are shown in Table 6, various analytical values are shown in Tables 7 to 9, various analytical values of the block copolymer are shown in Table 10, and solid physical property evaluation results are shown in Table 11, respectively.
[Examples 11 to 18 and Comparative Examples 9 to 16]

Examples 11 to 18 and Comparative Examples 9 to 16 were mixed with the block copolymers A shown in Tables 6 and 18 and the block copolymers shown in Table 10 and Table 22 except that they were mixed with the block copolymer A and the raw material charged block copolymer A. In the same manner as in Example 10, block copolymer A was synthesized, mixed with the block copolymer to produce a thermoplastic resin composition, and pellets were obtained. Various analysis values are shown in Tables 6 to 10 and Tables 18 to 22, and solid physical property evaluation results are shown in Tables 11 and 23.
In addition, the measurement after the completion of the second stage polymerization is performed under measurement condition 1 and the measurement after the completion of the third stage polymerization is performed under measurement condition 2, and the obtained block copolymer, block copolymer A and thermoplasticity are measured for GPC. The resin composition gel permeation chromatogram was measured under measurement condition 2.

  The block copolymers obtained in Examples 10 to 18 and Comparative Examples 9 to 16 and general-purpose polystyrene (manufactured by Toyo Styrene Co., Ltd .: G14L) are used as the block copolymers / general-purpose polystyrenes described in Table 12 and Table 24. After blending at a weight ratio of 20 mm, it was supplied to a 20 mm single screw extruder, and the molten strand was drawn from the die at 230 ° C., cooled with water, and cut with a cutter to obtain a pellet-shaped thermoplastic resin composition. Thereafter, the physical properties were evaluated in the same manner as in Example 1. The results are shown in Table 12 and Table 24.

The block copolymer and thermoplastic resin composition of the present invention are not only useful as molding materials for injection molding alone, but also various thermoplastic resins, thermosetting resin modifiers, footwear materials, adhesives / adhesives It can be used in applications where block copolymers have been used in the past, such as agent materials, asphalt modifiers, wire and cable materials, and vulcanized rubber modifiers.
In particular, the thermoplastic resin composition is effective as a material for sheets and films, making use of excellent transparency, impact resistance and low-temperature properties, as well as food packaging containers, daily miscellaneous goods packaging, laminate sheets and films. Can be used as well.

1 is a drawing-substitution transmission electron micrograph showing the microdomain structure of Example 1. FIG.

FIG. 3 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 2. FIG.

FIG. 6 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 3. FIG.

FIG. 5 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 4. FIG.

FIG. 7 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 5. FIG.

FIG. 6 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 6. FIG.

9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 7. FIG.

9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 8. FIG.

9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Example 9. FIG.

FIG. 6 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 1. FIG.

FIG. 9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 2. FIG.

FIG. 6 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 3. FIG.

FIG. 9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 4. FIG.

FIG. 9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 5. FIG.

FIG. 6 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 6. FIG.

FIG. 9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 7. FIG.

FIG. 9 is a drawing-substitute transmission electron micrograph showing the microdomain structure of Comparative Example 8. FIG.

Claims (12)

  A block copolymer comprising a hard segment block portion mainly composed of vinyl aromatic hydrocarbons and a soft segment block portion mainly composed of conjugated dienes, wherein a plurality of microdomain structures appear aperiodically. . The block copolymer according to claim 1, which satisfies the following i) to iii) simultaneously.
i) It consists of 35 to 95% by mass of vinyl aromatic hydrocarbon and 5 to 65% by mass of conjugated diene as monomer units.
ii) There are 2 to 3 types of hard segment block portions having different molecular weights.
iii) Molecular weight distribution (Mw / Mn) is in the range of 2-6.   When the two sets of hard segment block portions are S1 and S2, and the number average molecular weights of S1 and S2 are M1 and M2, M1 is in the range of 80000 to 160000 and M2 is in the range of 4000 to 10,000, and M1 and The ratio M1 / M2 of M2 is in the range of 13 to 22, and the ratio of S1 and S2 is in the range of S1 / S2 = 5 to 30/70 to 95 (molar ratio). The block copolymer as described. The block copolymer in any one of Claims 1-3 represented by following General formula (1).

S1-B1, S2-B1 and (S1-B1) iX- (B1-S2) m General formula (1)
(In the formula, S1 and S2 represent a hard segment block part mainly composed of vinyl aromatic hydrocarbon, B1 represents a soft segment block part mainly composed of conjugated diene, and X represents a coupling agent after coupling. I and m are integers of 0 or more, and i + m is 1 or more and 8 or less.   The block copolymer according to claim 4, wherein the coupling agent is an epoxidized oil.   6. The block copolymer according to claim 5, wherein the epoxidized fat is epoxidized soybean oil.   A thermoplastic resin composition comprising the block copolymer according to any one of claims 1 to 6 and a thermoplastic resin other than these. The other thermoplastic resin is the block copolymer A shown below, and the blending ratio of the block copolymer and the block copolymer A according to any one of claims 1 to 6 is 20 to 80 / It is 80-20, The thermoplastic resin composition of Claim 7 characterized by the above-mentioned.
The block copolymer A is characterized by satisfying the following a) to f) simultaneously.
A) As a monomer unit, it comprises 55 to 95% by mass of vinyl aromatic hydrocarbon and 5 to 45% by mass of conjugated diene.
B) Its structure consists of a hard segment block part mainly composed of vinyl aromatic hydrocarbons and a soft segment block part mainly composed of conjugated dienes.
C) The hard segment block portion has two block portions having different molecular weights represented by S3 and S4.
D) When the number average molecular weights M3 and M4 of S3 and S4 are set, M3 is in the range of 75000 to 170000 and M4 is in the range of 14000 to 30000.
E) The ratio M3 / M4 of M3 and M4 is in the range of 4-9.
F) The ratio of S3 and S4 is in the range of S3 / S4 = 6 to 35/65 to 94 (molar ratio). The thermoplastic resin composition according to claim 8, wherein the block copolymer A is represented by the following general formula (2).

S3-B2, S4-B2 and (S3-B2) nY- (B2-S4) o General formula (2)
(In the formula, S3 and S4 represent a hard segment block part mainly composed of vinyl aromatic hydrocarbon, B2 represents a soft segment block part mainly composed of conjugated diene, and Y represents a coupling agent after coupling. N and o are integers of 0 or more, and n + o is 1 or more and 8 or less.   The thermoplastic resin composition according to claim 9, wherein the coupling agent is an epoxidized oil.   The thermoplastic resin composition according to claim 7, wherein the thermoplastic resin other than those is the block copolymer A or the polystyrene according to claim 8, or a mixture of both.   A molded article molded using the block copolymer according to any one of claims 1 to 6 or the thermoplastic resin composition according to any one of claims 7 to 11.