JP2003138073A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition comprising a polypropylene-based resin and a polystyrene-based resin which excels in the stability of the dispersion state and excels in mechanical strength, moldability, surface properties of a molded product and the like. SOLUTION: The thermoplastic resin composition comprises 100 pts.mass composition composed of (i) 5-95 mass%; polypropylene-based resin and (ii) 5-95 mass% polystyrene-based resin and (iii) 1-30 pts.mass specific hydrogenated block copolymer comprising (A) a polymer block composed of a vinyl aromatic compound and (B) a polymer block having a specified conjugated diene structure.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition containing a polypropylene-based resin, a polystyrene-based resin and a hydrogenated block copolymer, and in particular, a specific hydrogenated block copolymer is used as a compatibilizer. The present invention relates to a thermoplastic resin composition having excellent mechanical strength, moldability, surface properties of a molded product, and the like.

[0002]

2. Description of the Related Art Olefin-based resins have high mechanical strength,
It is a general-purpose resin that is used in many industrial fields due to its excellent moldability and chemical resistance, but because it has high crystallinity and biaxial stretching is difficult, synthetic resin with high rigidity can be used instead of synthetic resin with low rigidity. Mixing to increase the rigidity than the original resin, and to mix the amorphous synthetic resin with the highly crystalline synthetic resin to facilitate biaxial stretching, for example, polystyrene resin to olefin resin, etc. Attempts have been made to compound it. here,
The polystyrene-based resin is a resin that is often used for modifying an olefin-based resin because it has excellent mechanical properties, but also has excellent electrical insulation properties, and particularly has good thermal stability and fluidity when melted.

On the other hand, since the olefin resin having high crystallinity is inferior in compatibility with the polystyrene resin, attempts have been made to improve the dispersibility by adding a compatibilizer to the olefin resin.
For example, JP-A-49-28637 discloses a compound which improves the compatibility between polyethylene and a styrene resin, and which contains a block copolymer composed of a conjugated diolefin and a monovinyl aromatic compound as a third component. A composition having excellent impact resistance is disclosed.

When blending a polystyrene resin and a polypropylene resin, a styrene elastomer such as hydrogenated styrene-butadiene block copolymer (SEBS) or hydrogenated styrene-isoprene block copolymer (SEPS) is used. Has been proposed as a compatibilizing agent, thereby improving mechanical properties, heat resistance, impact resistance and chemical resistance (for example, JP-A-56-38338 and JP-A-56-50943). Japanese Patent Laid-Open No. 1-17
4550, JP-A-2-173052, etc.).

Further, in JP-A-64-87645, when polystyrene resin particles are mixed as a dispersed phase in a polypropylene resin, a styrene-butadiene block copolymer (SBS) is used as a compatibilizing agent on the surface of the particles. ,
A composition in which a styrene-isoprene block copolymer (SIS) is present to improve mechanical properties and solid phase adhesion is disclosed.

[0006]

However, in the case of preparing a mixture of an olefin resin, particularly a polypropylene resin and a polystyrene resin, even if a styrene elastomer is added as a compatibilizer, the improvement may be insufficient. is there. Polypropylene resin has high crystallinity, so it has excellent mechanical strength, has a high deflection temperature under load, has excellent heat resistance, and has excellent water resistance, chemical resistance, electrical properties, and transparency. However, when a polystyrene-based resin is blended with a polypropylene-based resin, the melting temperature and melt viscosity are different, which makes it difficult to smoothly produce a composition even if a styrene-based elastomer is mixed as a compatibilizer. May be. Since SBS and SIS used in JP-A-64-87645 have a double bond in the molecular chain, they may gel during melt-kneading, or the molecules may be cut to deteriorate the surface condition of the molded product. is there.

Further, as a compatibilizer, SEBS or SEPS
However, when hydrogen peroxide is used, gelation such as SBS does not occur because hydrogen is added to the molecular chain, but the stability of the dispersed state is not always sufficient. Specifically, the stability of the dispersed state is a state in which particles that have once dispersed are gradually associated with each other even during molding and the dispersed particle size does not increase, and the particles are finely dispersed. However, when various styrenic elastomers are used as the compatibilizing agent, a difference in stability may occur due to a difference in compatibilizing ability of the compatibilizing agent. The finely dispersed particles have a greater effect on improving the physical properties, but the stability of the dispersed state is poor because the molding conditions such as the molding method, molding temperature, time, and shearing force affect the dispersed state. That is, when the compatibilizing ability of the compatibilizing agent is low, the dispersion state changes during the molding process, resulting in enlargement of the particles, and the effect of improving the physical properties is impaired, and the temperature, shear rate, residence time during molding, etc. Depending on the molding conditions, a molded product having good properties may not be obtained.

[0008]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that a polypropylene-based material which is not easily affected by molding conditions and the like, has excellent stability in a dispersed state, mechanical strength, moldability, surface properties of a molded article, and the like. As a result of intensive studies to obtain a thermoplastic resin composition containing a resin and a polystyrene resin, when a hydrogenated vinyl aromatic compound-based elastomer having a specific structure is used as a compatibilizer, excellent mechanical properties and dispersion stability are obtained. It is possible to obtain a thermoplastic resin composition having excellent properties, and even when a molding material in the form of pellets or powder is prepared from the composition, a molded article having excellent properties can be obtained by melt molding of the molding material. It was found that the present invention has been completed. That is, the present invention relates to polypropylene resin (A) 5 to 9
Polymer block (A) composed of at least one kind of vinyl aromatic compound, relative to 100 parts by mass of a composition composed of 5% by mass and 5 to 95% by mass of polystyrene resin (b).
And a hydrogenated polyisoprene block (b-1) in which the content of 1,2-bonds and 3,4-bonds is 40% mol or more and 70 mol% or more of carbon-carbon double bonds are hydrogenated. ,
A copolymer of a mixture of 40 to 95% by mass of isoprene and 60 to 5% by mass of butadiene, 1,2-bond and 3,4-
The total amount of bonds is 50 mol% or more, and the weight selected from the group consisting of any of hydrogenated copolymer blocks (b-2) obtained by hydrogenating 70% mol or more of carbon-carbon double bonds. (A)-(B) -consisting of a united block (B)
In the (A) type triblock copolymer, the number average molecular weight of the polymer block (A) made of a vinyl aromatic compound is 18
3,000 to 30,000, a thermoplastic resin composition containing 1 to 30 parts by mass of a hydrogenated block copolymer (C) in which the proportion of the polymer block (A) in the block copolymer is 40 to 70% by mass. Is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a polypropylene resin (a) 5 to 95 mass% and a polystyrene resin (b) 5 to
It is a thermoplastic resin composition containing 1 to 30 parts by mass of a specific hydrogenated block copolymer (c) per 100 parts by mass of a composition consisting of 95% by mass. Combined with the excellent mechanical properties of polypropylene-based resins and the excellent processability of polystyrene-based resins, polypropylene-based resins or polystyrene-based resins can be prepared by blending a specific hydrogenated block copolymer as a compatibilizer. The composition is finely dispersed in the resin composition and has excellent stability of the polypropylene resin in the resin composition. The present invention will be described in detail below.

The polypropylene resin (a) used in the thermoplastic resin composition of the present invention is not particularly limited as long as it is a crystalline polymer obtained by polymerizing propylene monomer as a main component. It is also possible to use random polypropylene, block polypropylene or the like containing copolymers such as, butene and 2-methylpentene-1. The polypropylene-based resin (a) to be added to the thermoplastic resin composition in the present invention includes
These 1 type may be used and 2 or more types may be used together. Furthermore, these polypropylene-based resins (a)
It may be modified with an unsaturated carboxylic acid or a derivative of an unsaturated carboxylic acid, or may have a functional group such as a hydroxyl group at the molecular end.

The polystyrene resin (b) to be added to the thermoplastic resin composition of the present invention includes homopolystyrene obtained by homopolymerizing styrene monomers, and copolymers such as α-methylstyrene, acrylonitrile, maleic anhydride and methylmethacrylate. Random polystyrene or block polystyrene copolymerized with can be used.
Examples of such polystyrene-based resin include polystyrene (GP), high-impact polystyrene (HIPS) containing a rubber or elastomer component, ABS resin, AES resin and the like. As the polystyrene-based resin (b) to be added to the thermoplastic resin composition in the present invention, these 1
Seeds may be used, or two or more types may be used in combination.

In the thermoplastic resin composition of the present invention,
The mixing ratio of the polypropylene resin (a) and the polystyrene resin (b) is 5 to 95 mass% of the polypropylene resin (a) and the polystyrene resin (b) when the total of the two is 100 mass%. Is to be adjusted to 5 to 95% by mass. The blending ratio of polypropylene resin (a) and polystyrene resin (b) is 5% by mass.
If it is below the range, the effect of improving the physical properties by mixing these resins may not be sufficiently exhibited.

In the present invention, the polypropylene resin (a) is 5 to 95% by mass, and the polystyrene resin (ii) is
With respect to 100 parts by mass of the composition composed of 5 to 95% by mass,
Polymer block (A) consisting of at least one kind of vinyl aromatic compound, the content of 1,2-bonds and 3,4-bonds is 40% by mol or more, and 70 mol% of carbon-carbon double bonds.
The above is a hydrogenated polyisoprene block (b-1) obtained by hydrogenation, a copolymer of a mixture of 40 to 95% by mass of isoprene and 60 to 5% by mass of butadiene, 1,2-bond and 3,4- The total amount of bonds is 50 mol% or more, and the weight selected from the group consisting of any of hydrogenated copolymer blocks (b-2) obtained by hydrogenating 70% mol or more of carbon-carbon double bonds. A block copolymer composed of a united block (B) and a polymer block (A) composed of a vinyl aromatic compound having a number average molecular weight of 18,000 to 30,000,
The ratio of the polymer block (A) in the block copolymer is 4
Hydrogenated block copolymer (C) 1 to 0 to 70% by mass
It contains 30 parts by mass.

In the hydrogenated block copolymer (C), as the vinyl aromatic compound constituting the polymer block (A) consisting of at least one kind of vinyl aromatic compound,
Styrene, α-methylstyrene, 1-vinylnaphthalene, 3-methylstyrene, 4-propylstyrene, 4-
Cyclohexyl styrene, 4-dodecyl styrene, 2-
Examples include ethyl-4-benzylstyrene and 4- (phenylbutyl) styrene. In the present invention, as the vinyl aromatic compound constituting the polymer block (A),
One of these may be used alone, or two or more may be used in combination. In the present invention, it is preferably a styrene homopolymer. The ratio of the polymer block (A) in the hydrogenated block copolymer (C) is 40 to 70% by mass,
More preferably 45 to 65 mass%, particularly preferably 50.
Is about 60% by mass. This is because when the amount is within this range, the effect as a compatibilizing agent for the polypropylene-based resin (a) and the polystyrene-based resin (b) described above is excellent.

The number average molecular weight of the polymer block (A) in the hydrogenated block copolymer (C) is 18000.
30,000, more preferably 19000-24000,
Particularly preferably, it is in the range of 20000-23000.
When the number average molecular weight is different, the melt viscosity and the melting temperature are also changed, but if the number average molecular weight of the polymer block (A) is in the above range, the polypropylene resin (a) and the polystyrene resin (b) are This is because, in the blending ratio, the effect as a compatibilizing agent for both is excellent.

The polymer block (B) constituting the hydrogenated block copolymer (C) has (i) 1,2-bond and 3,4-
Hydrogenated polyisoprene block (b-1) and (ii) isoprene 40 to 9 having a bond content of 40% mol or more and 70% by mol or more of a carbon-carbon double bond being hydrogenated.
It is a copolymer of a mixture of 5% by mass and 60 to 5% by mass of butadiene, and the total amount of 1,2-bonds and 3,4-bonds is 50.
Mol% or more and 70% or more of the carbon-carbon double bond is hydrogenated to give a hydrogenated copolymer block (b-
It is selected from any of 2).

In the hydrogenated polyisoprene block (b-1), the total amount of 1,2-bonds and 3,4-bonds is 40.
It is at least mol%, more preferably at least 45 mol%, particularly preferably at least 50 mol%. If it is less than 40 mol%, it may not be possible to obtain a thermoplastic resin composition having excellent mechanical properties. Similarly, the hydrogenated copolymer block (b-
The total amount of 1,2-bonds and 3,4-bonds in 2) is
It is 50 mol% or more, more preferably 55 mol% or more.

The hydrogenation rate of the carbon-carbon double bond in the polymer block (B) is 70 mol% or more, and more preferably 80 mol% in both (b-1) and (b-2). The above is particularly preferable, and it is 90 mol% or more. If the proportion of hydrogenation is less than 70 mol%, not only heat resistance and weather resistance are lowered, but also the effect of the block copolymer (C) as a compatibilizing agent is lowered, which is not preferable. That is, as the hydrogenation rate of the polydiene block decreases,
This is because the structural difference with the polypropylene resin is large and the compatibility is low, so the compatibility is low.

When the polymer block (B) is a copolymer of isoprene and butadiene, the binding form of isoprene and butadiene may be random type, tapered type or block type.

In the present invention, the bonding mode of the polymer block (A) and the polymer block (B) in the hydrogenated block copolymer (C) is shown by A for the polymer block (A), When (B) is indicated by B, AB
-Triblock type represented by A type.

The hydrogenated block copolymer (c) used in the present invention is obtained by reacting with an unsaturated carboxylic acid derivative in the presence of an organic peroxide in a twin-screw extruder or in a solution state. Also usable are those grafted with an unsaturated carboxylic acid derivative, or those obtained by reacting carbon dioxide gas or an epoxy compound with the active end of a polymer to introduce a carboxyl group or a hydroxyl group.

In the thermoplastic resin composition of the present invention, one of the hydrogenated block copolymers (c) having different polymer blocks (B) can be blended alone, but these two types can also be blended. You may use together the above.

The hydrogenated block copolymer (c) used in the present invention can be produced by a conventionally known method. For example, it can be manufactured by the following methods (a) to (c).

(A) After polymerizing a vinyl aromatic compound using an alkyllithium compound as an initiator, isoprene or a mixture of isoprene and butadiene is added thereto,
A method of polymerizing, further sequentially polymerizing a vinyl aromatic compound, and hydrogenating this.

(B) A method in which a vinyl aromatic compound and then isoprene or a mixture of isoprene and butadiene are polymerized and hydrogenated, and the resulting hydrogenated block copolymer is coupled using a coupling agent.

(C) A method in which isoprene or a mixture of isoprene and butadiene is polymerized using a dilithium compound as an initiator, and then a vinyl aromatic compound is added to successively polymerize and hydrogenate.

As the alkyllithium compound used in the method (a), an alkyllithium compound conventionally used for the polymerization of styrene elastomer can be widely used. For example, such a compound has an alkyl group having 1 carbon atom. There are alkyllithium compounds that are -10. In the present invention, methyl lithium, ethyl lithium, pentyl lithium, n-butyl lithium, s-butyl lithium,
t-Butyl lithium and the like can be preferably used.

As the coupling agent used in the method (b), the coupling agents conventionally used for the polymerization of styrene elastomer can be widely used. For example, halogen compounds such as dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene and tin tetrachloride; monoester compounds such as phenyl benzoate and ethyl acetate; epoxy compounds having two epoxy groups in the molecule; dimethoxysilane, Examples thereof include silane compounds such as diethoxysilane.

As the polymerization initiator used in the method (c), the dilithium compounds conventionally used for the polymerization of styrene elastomer can be widely used. Examples of such a dilithium compound include naphthalenedilithium and dilithiohexylbenzene.

In the above methods (a) to (c), the amount of the above-mentioned initiator or coupling agent used can be appropriately selected according to the desired molecular weight of the block copolymer (c).

The content of 1,2-bonds and 3,4-bonds in the polymer block (B) in the hydrogenated block copolymer (C) is determined by using a Lewis base as a cocatalyst during the polymerization. It can be controlled by Examples of the Lewis base include ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran; glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; triethylamine, N, N, N ′, N′-tetramethylethylenediamine (hereinafter, referred to as (Abbreviated as TMEDA), and amine compounds such as N-methylmorpholine. The amount of the Lewis base used is not particularly limited, but it is generally preferably within the range of 0.1 to 1000 mol per mol of lithium atom contained in the initiator.

At the time of polymerization, an organic solvent inert to the polymerization reaction is used as a solvent. As such a solvent,
It is preferable to use aliphatic hydrocarbons having 6 to 12 carbon atoms such as hexane and heptane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and aromatic hydrocarbons such as benzene.

Polymerization is usually carried out in the temperature range of 0 to 80 ° C., regardless of the polymerization method of (a) to (c).
The reaction time is usually 0.5 to 50 hours. The hydrogenation condition is that the polymer block obtained by copolymerization before hydrogenation is dissolved in a solvent inert to the reaction, and hydrogen in a molecular state is reacted with a known hydrogenation catalyst. As a result, the hydrogenated block copolymer (c) can be obtained.

Examples of the hydrogenation catalyst that can be used here include Raney nickel, a heterogeneous catalyst in which a metal such as Pt, Pd, Ru, Rh, and Ni is supported on a carrier such as carbon, alumina, and diatomaceous earth, and nickel, VIII such as cobalt
Ziegler-based catalysts composed of a combination of an organometallic compound consisting of a group metal and an organoaluminum compound such as triethylaluminum or triisobutylaluminum, or an organolithium compound, and further a transition metal bis (cyclo Pentadienyl) compound and lithium, sodium, potassium,
A metallocene catalyst composed of a combination of organometallic compounds such as aluminum, zinc or magnesium can be used. For hydrogenation, the hydrogen pressure is usually atmospheric pressure to
It is carried out at a pressure of 30 MPa and a reaction temperature in the range of normal temperature to 250 ° C. The reaction time required for hydrogenation is usually 0.1 to 10
It's 0 hours.

The hydrogenated block copolymer (C) obtained by hydrogenation may be obtained by coagulating the reaction mixture (i) with methanol or the like, followed by heating or drying under reduced pressure.
i) The reaction solution can be obtained by pouring the reaction solution into boiling water, subjecting the solvent to azeotropic removal of the solvent by so-called steam stripping, and then heating or drying under reduced pressure.

In the present invention, such a hydrogenated block copolymer (c) is used as a composition 100 comprising a polypropylene resin (a) 5 to 95 mass% and a polystyrene resin (b) 5 to 95 mass%. 1 to 30 parts by mass are blended with respect to parts by mass. If the blending amount of the hydrogenated block copolymer (C) is less than 1 part by mass, the polypropylene resin (A) is
In some cases, the compatibility between the resin and the polystyrene-based resin (B) may be insufficient, while on the other hand, even if it exceeds 30% by mass, there is little change in the improvement of the compatibility itself.

Generally, when the polystyrene resin (ii) is mixed with the polypropylene resin (ii) for the purpose of modifying the polypropylene resin (ii), the polypropylene resin (ii) is used as a matrix and the polystyrene resin (ii) is used. It is important how to form a phase structure in which a large amount of () is uniformly dispersed. On the contrary, when the polypropylene resin (ii) is mixed with the polystyrene resin (ii) for the purpose of modifying the polystyrene resin (ii), the polystyrene resin (ii) is used as a matrix and the polypropylene resin (ii) is used. It is important how to form a phase structure in which a large amount of fine particles are uniformly dispersed. In the thermoplastic resin composition of the present invention, the above object can be achieved by using the hydrogenated block copolymer (c) as the compatibilizing agent.

Further, generally, when two kinds of different resins are mixed, the larger volume ratio at the time of mixing becomes the matrix. For example, even if the purpose is to modify the polypropylene resin (a), if the polystyrene resin (b) is contained in a high proportion, the phase will be polystyrene resin (b) instead of polypropylene resin (a) as a matrix. The structure is formed, and the obtained resin composition comes close to the characteristics of the polystyrene resin (b). However, in the thermoplastic resin composition of the present invention, by using the hydrogenated block copolymer (c) as a compatibilizing agent, the polypropylene resin (a) can be used at a mixing ratio within a specific range.
It is also possible to form a phase structure opposite to the phase structure expected from the mixing ratio of the polystyrene resin (b).

That is, the ratio of polypropylene resin (a) and polystyrene resin (b) is (a) / (b) = 3.
By using the hydrogenated block copolymer (c) as a compatibilizing agent under the condition of 0/70 to 50/50 (mass ratio), polypropylene can be used even when the proportion of the polypropylene resin (a) is small. It is possible to obtain a thermoplastic resin composition having a phase structure in which the polystyrene resin (b) is dispersed with the resin (a) as a matrix.

On the contrary, polypropylene resin (a)
And the ratio of polystyrene resin (ii) is (ii) / (ii) =
By using the hydrogenated block copolymer (c) as a compatibilizing agent under the condition of 70/30 to 50/50 (mass ratio), the polystyrene-based resin (b) can be used even if the compounding ratio is low. It is possible to obtain a thermoplastic resin composition having a phase structure in which the polypropylene resin (a) is dispersed with the resin (b) as a matrix.

The thermoplastic resin composition of the present invention contains an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, a crystal nucleating agent, a flame retardant, an antibacterial agent, and an inorganic filler as long as the properties thereof are not impaired. Various additives such as agents and foaming agents can be added. The amount of these additives used can be appropriately selected depending on the desired performance and purpose of use, but is usually in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin composition, and the flame retardant and inorganic filler. In the case of an agent, it may be used in an amount exceeding 100 parts by mass.

Further, the thermoplastic resin composition of the present invention is, for example, hydrogenated polyisoprene, hydrogenated polybutadiene, hydrogenated styrene-butadiene random copolymer, hydrogenated, as long as it does not impair the gist of the invention. Styrene-isoprene random copolymer, hydrogenated styrene-butadiene block copolymer other than the hydrogenated block copolymer (c) used in the present invention, hydrogenated styrene-isoprene block copolymer,
Hydrogenated styrene- (isoprene / butadiene) block copolymer, butyl rubber, polyisobutylene, polybutene,
Ethylene-propylene rubber, polyethylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer and ionomers thereof, ethylene-ethyl acrylate Other polymers such as copolymers and atactic polypropylene can be blended.

The thermoplastic resin composition of the present invention is prepared by mixing the polypropylene-based resin (a) with the polystyrene-based resin (b) and further by adding the above-mentioned other polymers and mixing them. It can be prepared by blending the hydrogenated block copolymer (c) with a kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or a roll. Further, this may be prepared into a pellet or a powdery molding material.

The thermoplastic resin composition of the present invention is not only excellent in compatibility between the polypropylene resin (a) and the polystyrene resin (b), but also the polypropylene resin is finely dispersed in the thermoplastic resin composition. And, the dispersibility is maintained extremely stable. Therefore, even if a molded product obtained by further melting the composition prepared as pellets and then molding it is a molded product with less occurrence of tears and a good surface condition. .

The thermoplastic resin composition of the present invention can be formed into a film, a sheet, a fibrous molded product, a tubular molded product or the like by any molding method such as injection molding, blow molding, press molding, extrusion molding, calender molding and the like. Can be molded into. The thermoplastic resin composition of the present invention has mechanical strength,
Since it has excellent moldability and surface characteristics of the molded product, for example, food containers such as cups and trays, packaging materials, toys,
Used for stationery, adhesive tape substrates, protective films, wallpaper, etc.

[0046]

EXAMPLES The present invention will be specifically described below with reference to examples. The styrene content of the hydrogenated block polymer in the reference example, the number average molecular weight, the vinyl bond content and the hydrogenation rate, the dispersed particle diameter in the examples, the flexural modulus, the moldability evaluation, and the surface state are the following methods. Sought by.

(Measurement Method) (1) Styrene Content of Hydrogenated Block Copolymer The styrene content was calculated from the mass of each monomer component used in the polymerization.

(2) Number average molecular weight of hydrogenated block copolymer The number average molecular weight was determined from the polystyrene equivalent number average molecular weight (Mn) by GPC measurement.

(3) Content of 1,2-bonds and 3,4-bonds of hydrogenated block copolymer (amount of vinyl bond) ¹ H-NMR spectrum of the block copolymer before hydrogenation was measured and The vinyl bond content was calculated from the size of the peak corresponding to the 2,2-bond or the 3,4-bond.

(4) Hydrogenation rate of hydrogenated block copolymer The iodine value of the block copolymer before and after hydrogenation was measured and calculated from the measured value.

(5) Dispersed particle size In the thermoplastic resin compositions prepared in the following Examples and Comparative Examples, a strand before pelletizing and a test piece for bending elastic modulus measurement prepared by injection molding after pelletization were prepared. After fracture in liquid nitrogen, the samples obtained for each were immersed in toluene for 5 minutes to extract polystyrene and hydrogenated block copolymer, and then the fracture surface of each sample was observed with a scanning electron microscope (SEM). I observed. The next diameter generated by extraction in the remaining polypropylene portion was measured, and the average value was calculated for each sample to obtain the dispersed particle diameter of the pellet and the dispersed particle diameter after molding.

(6) Flexural modulus It was performed according to JIS K7171.

(7) Moldability evaluation It was observed with the naked eye and evaluated as follows.

[0054] ○: A uniform film can be formed ×: Sometimes tears occur XX: Tear frequently occurs (8) Surface condition of molded body It was observed with the naked eye and evaluated as follows.

◯: The surface smoothness is good. ×: There is a pattern due to uneven thickness. XX: There is a marked uneven thickness, and there is a pattern (Reference Example 1: Production of hydrogenated block copolymer (1)). 2700 g of cyclohexane was charged as a solvent into a pressure vessel replaced with nitrogen, and sec- was used as a polymerization initiator.
Butyllithium (0.27 g) was added to polymerize styrene (75 g) at 40 ° C. Then, 14 g of tetrahydrofuran as a Lewis base was added, and then 150 g of isoprene,
Further, 75 g of styrene was sequentially added and polymerized to obtain a styrene-isoprene-styrene type triblock copolymer. 300 g of the obtained triblock copolymer was added to 2700 g of cyclohexane with 2MP using Pd / C as a catalyst.
Hydrogenation treatment was carried out under the hydrogen atmosphere of a to obtain a hydrogenated block copolymer. This hydrogenated block copolymer is referred to as hydrogenated block copolymer (1). Table 1 shows the styrene content, number average molecular weight, vinyl bond content, and hydrogenation rate of the obtained hydrogenated block copolymer (1).

Reference Example 2: Hydrogenated block copolymer (2)
Preparation of cyclohexane solvent 2 in the same manner as in Reference Example 1.
0.27 g of sec-butyllithium was added to 700 g to polymerize 75 g of styrene. Next, 15 g of tetrahydrofuran and a mixture of isoprene and butadiene [isoprene / butadiene = 50/50 (mass ratio)] 1
Styrene- (isoprene / butadiene) -styrene type triblock copolymer was obtained by sequentially adding 50 g and further 75 g of styrene and polymerizing. The hydrogenated block copolymer was obtained by hydrogenating the obtained triblock copolymer in the same manner as in Reference Example 1. This is designated as a hydrogenated block copolymer (2). Table 1 shows the styrene content, number average molecular weight, vinyl bond content and hydrogenation rate of the obtained hydrogenated block copolymer (2).

Reference Example 3: Hydrogenated block copolymer (3)
Preparation of cyclohexane solvent 2 in the same manner as in Reference Example 1.
Using 700 g of sec-butyllithium as an initiator, 97.5 g of styrene and 105 of isoprene.
g and 97.5 g of styrene are sequentially added to cause polymerization,
A styrene-isoprene-styrene type triblock copolymer was obtained. The triblock copolymer thus obtained was hydrogenated in the same manner as in Reference Example 1 to obtain a hydrogenated block copolymer (3). Table 1 shows the styrene content, the number average molecular weight, the vinyl bond content, and the hydrogenation rate of the obtained hydrogenated block copolymer (3).

Reference Example 4: Hydrogenated block copolymer (4)
Preparation of cyclohexane solvent 2 in the same manner as in Reference Example 1.
0.30 g of sec-butyllithium was added to 700 g to polymerize 90 g of styrene. Thereafter, 5.5 g of tetrahydrofuran, 120 g of butadiene, and further 90 g of styrene were sequentially added and polymerized to obtain a styrene-butadiene-styrene type triblock copolymer.
The obtained triblock copolymer was hydrogenated in the same manner as in Reference Example 1 to obtain a hydrogenated block copolymer. This is designated as a hydrogenated block copolymer (4). Table 1 shows the styrene content, number average molecular weight, vinyl bond content and hydrogenation rate of the obtained hydrogenated block copolymer (4).

Reference Example 5: Hydrogenated Block Copolymer (5)
Preparation of cyclohexane solvent 2 in the same manner as in Reference Example 1.
To 700 g, 0.15 g of sec-butyllithium was added to polymerize 45 g of styrene. Then, 12 g of tetrahydrofuran, 210 g of isoprene, and 45 g of styrene were sequentially added and polymerized to obtain a styrene-isoprene-styrene type triblock copolymer. The hydrogenated block copolymer was obtained by hydrogenating the obtained triblock copolymer in the same manner as in Reference Example 1. This is designated as a hydrogenated block copolymer (5). Table 1 shows the styrene content, number average molecular weight, vinyl bond content and hydrogenation rate of the obtained hydrogenated block copolymer (5).

Reference Example 6: Hydrogenated block copolymer (6)
Preparation of cyclohexane solvent 2 in the same manner as in Reference Example 1.
0.29 g of sec-butyllithium was added to 700 g to polymerize 120 g of styrene. Thereafter, 13 g of tetrahydrofuran, 60 g of isoprene, and 120 g of styrene were sequentially added and polymerized to obtain a styrene-isoprene-styrene type triblock copolymer.
The hydrogenated block copolymer was obtained by hydrogenating the obtained triblock copolymer in the same manner as in Reference Example 1. This is designated as a hydrogenated block copolymer (6). Table 1 shows the styrene content, number average molecular weight, vinyl bond content, and hydrogenation rate of the obtained hydrogenated block copolymer (6).

Reference Example 7: Hydrogenated Block Copolymer (7)
Preparation of cyclohexane solvent 2 in the same manner as in Reference Example 1.
0.36 g of sec-butyllithium was added to 700 g to polymerize 150 g of styrene. Then, 14 g of tetrahydrofuran and 150 g of isoprene were added,
Polymerization was performed to obtain a styrene-isoprene type diblock copolymer. The obtained diblock copolymer was used in Reference Example 1
Hydrogenation was performed in the same manner as in 1. to obtain a hydrogenated block copolymer. This is designated as a hydrogenated block copolymer (7). Table 1 shows the styrene content, number average molecular weight, vinyl bond content and hydrogenation rate of the obtained hydrogenated block copolymer (7).

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[Table 1]

Examples 1 and 2 and Comparative Examples 1 to 6 Hydrogenated block copolymers (1) to (7) obtained in Reference Examples 1 to 7
Polystyrene and polypropylene were added according to the formulation shown in Table 2 and melt-kneaded with a twin-screw extruder at a cylinder temperature of 200 ° C. to prepare a thermoplastic resin composition, which was then extruded in a strand shape. The extruded strand was water-cooled and then pelletized with a strand cutter. At this time, the water-cooled strand was sampled, and the dispersed particle size of the pellet was measured by the method described above.

Next, the pellets were heated to a cylinder temperature of 200.
Injection molding at ℃ to form a test piece for flexural modulus measurement,
Using the test piece, the flexural modulus and the dispersed particle size of the cross section of the molded product were measured by the methods described above. The measurement results are shown in Table 2.

(Examples 3 to 4 and Comparative Examples 7 to 12) Hydrogenated block copolymers (1) to (7) obtained in Reference Examples 1 to 7
Polystyrene and polypropylene were added according to the formulation shown in Table 3, and the film was formed with a T-die extruder at a barrel temperature of 210 ° C. to obtain a film having a thickness of 30 μm. The moldability and the surface of the obtained film were observed. The results are shown in Table 3.

(Examples 5-6 and Comparative Examples 13-14)
Polystyrene and polypropylene were added to the hydrogenated block copolymers (1), (2) and (3) obtained in Reference Examples 1, 2 and 3 according to the formulation shown in Table 4, and the twin screw extruder was used at a cylinder temperature of 200 ° C. Was melt-kneaded to prepare a thermoplastic resin composition, and then extruded into a strand. The extruded strand was water-cooled and then pelletized with a strand cutter. At this time, the water-cooled strand was sampled, and the dispersed particle size of the pellet was measured by the method described above. The results are shown in Table 4.

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[Table 2]

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[Table 3]

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[Table 4]

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EFFECT OF THE INVENTION By using a hydrogenated block copolymer having a specific structure as a compatibilizing agent when blending a polystyrene resin and a polypropylene resin, a thermoplastic resin composition having excellent dispersibility and dispersion stability is obtained. You can get things. The composition is excellent in mechanical strength, moldability, and surface properties of a molded product, and when a molding material such as pellets is prepared and melt-molded, the polypropylene-based resin and the polystyrene-based resin in the molded product Since it has excellent dispersibility with, it is possible to suppress the occurrence of tears and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Takamatsu             36 Towada Stock Exchange, Kamisu Town, Kashima District, Ibaraki Prefecture             Inside the company Kuraray F term (reference) 4J002 BB12W BB14W BC03X BC06X                       BC07X BN07X BN15X BP01Y                       BP03W BP03X GG01 GG02

Claims (3)

[Claims] 1. A weight of at least one vinyl aromatic compound based on 100 parts by weight of a composition of polypropylene resin (a) 5 to 95% by mass and polystyrene resin (b) 5 to 95% by mass. Combined block (A), hydrogenated polyisoprene block in which the content of 1,2-bonds and 3,4-bonds is 40% or more and 70% or more of carbon-carbon double bonds are hydrogenated (B-1) is a copolymer of a mixture of 40 to 95% by mass of isoprene and 60 to 5% by mass of butadiene, and is 1,2-
The total amount of bonds and 3,4-bonds is 50 mol% or more,
A polymer block (B) selected from the group consisting of any of hydrogenated copolymer blocks (b-2) obtained by hydrogenating 70% or more of carbon-carbon double bonds (A)- (B)-(A) type triblock copolymer,
The number average molecular weight of the polymer block (A) composed of a vinyl aromatic compound is 18,000 to 30,000, and the proportion of the polymer block (A) in the block copolymer is 40 to 70% by mass.
A thermoplastic resin composition containing 1 to 30 parts by mass of the hydrogenated block copolymer (C). 2. The ratio of polypropylene resin (a) and polystyrene resin (b) is (a) / (b) = 30/70.
The thermoplastic resin according to claim 1, wherein the thermoplastic resin has a phase structure in which the polystyrene resin (b) is dispersed with the polypropylene resin (a) as a matrix. Composition. 3. The ratio of polypropylene resin (a) and polystyrene resin (b) is (a) / (b) = 70/30.
The thermoplastic resin according to claim 1, wherein the thermoplastic resin has a phase structure in which the polypropylene resin (a) is dispersed with the polystyrene resin (b) as a matrix. Composition.