JP6944786B2 - Resin composition and low temperature molded article - Google Patents

Description

The present invention relates to a resin composition for producing a molded product (molded product for low temperature) capable of achieving high impact resistance under low temperature conditions, and a molded product obtained by molding the resin composition.

In recent years, resin compositions composed of vinyl aromatic hydrocarbons and conjugated diene and containing a block copolymer having a relatively high content of vinyl aromatic hydrocarbons have been widely used in the packaging field. In particular, polystyrene-based sheets using a resin composition in which a block copolymer composed of styrene and butadiene and general-purpose polystyrene (GPPS, General Purpose Polymer) are mixed have excellent impact resistance and other characteristics of the molded product. Therefore, it is widely used as a packaging container for foods and miscellaneous goods. Various proposals have been made for these sheets and containers with the aim of further improving the characteristics such as impact resistance.

Japanese Unexamined Patent Publication No. 2009-29868 Japanese Unexamined Patent Publication No. 2013-144575 Japanese Unexamined Patent Publication No. 8-193161 Japanese Unexamined Patent Publication No. 6-184400 Japanese Unexamined Patent Publication No. 2003-183474 Japanese Unexamined Patent Publication No. 2003-55526

The present invention is a resin composition for producing a molded article (molded article for low temperature) capable of achieving high impact resistance under low temperature conditions without deteriorating other properties such as transparency and tensile elastic modulus. An object of the present invention is to provide a molded product obtained by molding the resin composition.

That is, the present invention is as follows.
(1) The content ratio of the following (A) and (B) to 100 parts by mass is (A) / (B) = 30/70 to 85/15 (mass ratio), and the following (A) and (B) ) Is a resin composition in which the content ratio of the following (C) is 0.3 to 7 parts by mass with respect to 100 parts by mass, and is used for producing a molded product capable of achieving high impact resistance under low temperature conditions. Resin composition.
(A); A block copolymer-containing resin composition of a vinyl aromatic hydrocarbon and a conjugated diene satisfying the following (a-1) to (a-4).
(A-1); Contains two or more types of block copolymers of vinyl aromatic hydrocarbons and conjugated diene.
(A-2); The melt mass flow rate (MFR) measured under the conditions of 200 ° C. and 49 N load is 10 g / 10 minutes to 30 g / 10 minutes.
(A-3); The content ratio of conjugated diene in the total amount of 100% by mass of the block copolymer-containing resin composition (A) is 19 to 33% by mass.
(A-4); The loss tangent (tan δ) obtained by dynamic viscoelasticity measurement has one maximum value (tan δ (max) value) in the temperature range of -100 to -30 ° C, and the temperature of the maximum value. The value obtained by dividing the tan δ value (tan δ (max + 30 ° C.) value) when the temperature is 30 ° C. higher than (tan δ peak temperature) by the maximum value (tan δ (max) value) is 0.6 or more.
(B); Polystyrene satisfying the following (b-1).
(B-1); The peak top molecular weight (Mp) obtained by gel permeation chromatography (GPC) is 230,000 to 400,000.
(C); A rubber-modified vinyl aromatic hydrocarbon-based polymer obtained by graft-polymerizing a vinyl aromatic hydrocarbon onto a conjugated diene-based rubber-like polymer that satisfies the following (c-1) and (c-2).
(C-1); The volume-medium particle size of the rubber-like dispersed particles is 1 to 4 μm.
(C-2); The gel content of the rubber-like dispersed particles is 12 to 20% by mass.
(2) The block copolymer-containing resin composition (A) satisfies the following (a-5) and (a-6), polystyrene (B) satisfies the following (b-2), and rubber-modified vinyl aromatic hydrocarbons. The resin composition according to (1), wherein the hydrogen-based polymer (C) satisfies the following (c-3).
Block copolymer-containing resin composition (A)
(A-5); The blocking ratio of vinyl aromatic hydrocarbons is 85 to 100% by mass.
(A-6); Mw / Mn obtained by gel permeation chromatography (GPC) is 1.1 to 3.5 (where Mw: weight average molecular weight, Mn: number average molecular weight).
Polystyrene (B)
(B-2); Mw / Mn obtained by gel permeation chromatography (GPC) is 1.9 to 2.4 (where Mw: weight average molecular weight, Mn: number average molecular weight).
Rubber-modified vinyl aromatic hydrocarbon-based polymer (C)
(C-3); Mw / Mn obtained by gel permeation chromatography (GPC) is 2.3 to 2.6 (however, Mw: weight average molecular weight, Mn: number average molecular weight).
(3) The block copolymer-containing resin composition (A) contains a block copolymer (i) of a vinyl aromatic hydrocarbon and a conjugated diene satisfying the following (i-1), and the following (ii-1). The resin composition according to (1) or (2), which contains a block copolymer (ii) of a vinyl aromatic hydrocarbon and a conjugated diene to be satisfied.
(I-1); In the gel permeation chromatogram, the peak top molecular weight (Mp) has at least one peak in the range of 105,000 to 250,000.
(Ii-1); In the gel permeation chromatogram, the peak top molecular weight (Mp) has at least one peak in the range of 40,000 to 140,000.
(4) The block copolymer (i) of the vinyl aromatic hydrocarbon and the conjugated diene constituting the block copolymer-containing resin composition (A) satisfies the following (i-2), and the vinyl aromatic hydrocarbon. The resin composition according to (3), wherein the block copolymer (ii) of and the conjugated diene satisfies the following (ii-2).
(I-2); The content ratio of conjugated diene is 10 to 20% by mass with respect to 100% by mass of the block copolymer (i).
(Ii-2); The content ratio of the conjugated diene is 27 to 60% by mass with respect to 100% by mass of the block copolymer (ii).
(5) The block copolymers (i) and (ii) of the vinyl aromatic hydrocarbon and the conjugated diene constituting the block copolymer-containing resin composition (A) are (i) / (ii) = 15. The resin composition according to (3) or (4), which satisfies / 85-60/40 (mass ratio).
(6) The resin composition according to any one of (1) to (5), wherein the vinyl aromatic hydrocarbon is styrene and the conjugated diene is 1,3-butadiene.
(7) A molded product obtained by molding the resin composition according to any one of 1 to 6 and capable of achieving high impact resistance under low temperature conditions.
(8) A molded product that is a sheet or container and can achieve high impact resistance under the low temperature conditions according to (7).

According to the present invention, it is possible to provide a low-temperature molded product capable of achieving high impact resistance under low-temperature conditions without deteriorating other properties such as transparency and tensile elastic modulus.

Hereinafter, one embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications as long as the effects of the present invention are not impaired.

[Resin composition]
The low-temperature molded product of the present invention contains a block copolymer-containing resin composition (A), polystyrene (B), and a rubber-modified vinyl aromatic hydrocarbon-based polymer (C) having the following characteristics, respectively. It is obtained by molding a resin composition.

<Block Copolymer-Containing Resin Composition (A)>
The block copolymer-containing resin composition (A) contains two or more types of block copolymers composed of vinyl aromatic hydrocarbons and conjugated diene. That is, it is a mixture consisting of two or more types of block copolymers of vinyl aromatic hydrocarbons and conjugated diene. When there is only one type of block copolymer, it is not preferable because the impact strength of the sheet and the container as a molded product is lowered. Further, additives and other resins may be used in combination as long as the effects of the present invention are not impaired.

The two or more types of block copolymers contained in the block copolymer-containing resin composition (A) are a polyvinyl aromatic hydrocarbon block composed of a vinyl aromatic hydrocarbon and a polyconjugated diene block composed of a conjugated diene. , And a structure in which a random block composed of a vinyl aromatic hydrocarbon and a conjugated diene is arbitrarily combined is preferable. The random block is a structure obtained by adding vinyl aromatic hydrocarbons and conjugated diene to the reaction vessel at a constant flow rate and randomly polymerizing the vinyl aromatic hydrocarbons and the conjugated diene. The randomized state of the random block moiety can be adjusted by the rate of addition of vinyl aromatic hydrocarbons and conjugated diene, the polymerization temperature and the concentration of the randomizing agent.

Examples of vinyl aromatic hydrocarbons include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, α-methylstyrene, vinylnaphthalene, and vinyl. Anthracene and the like can be mentioned. In particular, styrene is preferable. Not only one type of vinyl aromatic hydrocarbon but also two or more types may be used.

Examples of the conjugated diene include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like. Be done. In particular, 1,3-butadiene or isoprene is preferable. Not only one type of conjugated diene but also two or more types may be used.

The block copolymer-containing resin composition (A) contains at least two or more block copolymers having different molecular weights. The chemical structure of such a block copolymer is preferably represented by the following general formulas (I) to (IV) and contains a block copolymer of at least two vinyl aromatic hydrocarbons having different molecular weights and a conjugated diene. It is preferable to do so.
S- (RS) n-RS (I)
(S- (RS) n-RS) m-X (II)
S- (BS) n-BS (III)
(S- (BS) n-BS) m-X (IV)

In the general formulas (I) to (IV), S is a polymer block having a vinyl aromatic hydrocarbon as a monomer unit, and R is a random having a vinyl aromatic hydrocarbon and a conjugated diene as a monomer unit. It is a copolymer block, and B is a polymer block having a conjugated diene as a monomer unit. m represents the number of polymer chains bound to the coupling agent residue. m is an integer of 1 or more, preferably 2 to 10, and more preferably 2 to 5. n represents the number of repeating units and is an integer of 1 or more. From the viewpoint of the simplicity of the polymerization operation, n is preferably 1 to 5, and more preferably 1 to 3. X represents the residue of the coupling agent.

When the block copolymer has such a chemical structure, the impact resistance of the low-temperature molded product becomes more excellent.

In the general formulas (I) to (IV), the molecular weight of S sandwiched between R or B is not particularly limited, but is preferably 600 or more, more preferably 600 to 20,000. When the molecular weight of S sandwiched between R or B is 600 or more, the distinction between a random block and a conjugated diene polymer block becomes clearer when measuring the block ratio, and the block ratio can be measured accurately and easily. That is, it is preferable that the boundary between R or B and S is clearly distinguished, and the degree of polymerization of S sandwiched between R or B is preferably 6 or more. Further, when the molecular weight of S sandwiched between R or B is 20,000 or less, the molecular weight between entangled points (Me) of general polystyrene is not exceeded. Therefore, the hard segment block S sandwiched between the soft segment blocks R or B is taken into the soft segment block R or B, and the S sandwiched between the R or B can be apparently regarded as the soft segment block. Physical properties such as impact strength are more likely to be expressed.

Block copolymers of vinyl aromatic hydrocarbons represented by the general formulas (I) to (IV) and conjugated diene can be obtained by living anionic polymerization as described later.

The block copolymer-containing resin composition (A) particularly satisfies the block copolymer (i) of a vinyl aromatic hydrocarbon and a conjugated diene satisfying the following (i-1) and the following (ii-1). It preferably contains a block copolymer (ii) of a vinyl aromatic hydrocarbon and a conjugated diene.
(I-1); In the gel permeation chromatogram, the peak top molecular weight (Mp) has at least one peak in the range of 105,000 to 250,000.
(Ii-1); In the gel permeation chromatogram, the peak top molecular weight (Mp) has at least one peak in the range of 40,000 to 140,000.

In the above (i-1) and (ii-1), the peak top molecular weight (Mp) is obtained from the position of the apex of the peak of the molecular weight distribution obtained by gel permeation chromatography (GPC). In GPC, when it has a plurality of peaks, it is the molecular weight of the peak corresponding to the peak having the largest area ratio. When coupling is carried out, it means the peak top molecular weight before coupling.

When the peak top molecular weight (Mp) of the block copolymer (i) is 105,000 or more, the decrease in impact resistance can be further suppressed. When the peak top molecular weight (Mp) of the block copolymer (i) is 250,000 or less, the decrease in transparency can be further suppressed. In particular, the peak top molecular weight (Mp) is preferably 105,000 to 220,000, and particularly preferably 120,000 to 220,000.

Further, when the peak top molecular weight (Mp) of the block copolymer (ii) is 40,000 or more, the decrease in rigidity and transparency can be further suppressed. Further, when the peak top molecular weight (Mp) of the block copolymer (ii) is 140,000 or less, the decrease in impact strength can be further suppressed. In particular, the peak top molecular weight (Mp) is preferably 40,000 to 120,000, and particularly preferably 60,000 to 120,000.

The block copolymer-containing resin composition (A) particularly satisfies the block copolymer (i) of a vinyl aromatic hydrocarbon and a conjugated diene satisfying the following (i-2) and the following (ii-2). It preferably contains a block copolymer (ii) of a vinyl aromatic hydrocarbon and a conjugated diene.
(I-2); The content ratio (mass) of the conjugated diene is 10 to 20% by mass.
(Ii-2); The content ratio (mass) of the conjugated diene is 27 to 60% by mass.

In the above (i-2), when the content ratio (mass) of the conjugated diene of the block copolymer (i) is 10% by mass or more, the decrease in impact resistance can be further suppressed. When the content ratio (mass) of the conjugated diene of the block copolymer (i) is 20% by mass or less, the decrease in rigidity can be further suppressed. In particular, the content ratio (mass) of the conjugated diene of the block copolymer (i) is preferably 10 to 18% by mass, and particularly preferably 11 to 18% by mass.

In the above (ii-2), when the content ratio (mass) of the conjugated diene of the block copolymer (ii) is 27% by mass or more, the decrease in impact resistance can be further suppressed. When the content ratio (mass) of the conjugated diene of the block copolymer (ii) is 60% by mass or less, the decrease in rigidity can be further suppressed. In particular, the content ratio (mass) of the conjugated diene of the block copolymer (ii) is preferably 27 to 40% by mass, more preferably 27 to 38% by mass, and particularly preferably 29 to 37% by mass.

The content of the block copolymer (i) and the block copolymer (ii) in the block copolymer-containing resin composition (A) is (i) / (ii) = 15/85 to 60/40 (mass). Ratio) is preferable. That is, it is preferably 15/85 or more and 60/40 or less. By setting (i) to 15% by mass or more and (ii) to 85% by mass or less, deterioration of rigidity and transparency can be further suppressed. On the other hand, by setting (i) to 60% by mass or less and (ii) to 40% by mass or more, a decrease in impact resistance can be further suppressed. For (i) / (ii), 15/85 to 50/50 is more preferable, and 25/75 to 50/50 is particularly preferable. That is, 15/85 or more and 50/50 or less are more preferable, and 25/75 or more and 50/50 or less are particularly preferable.

In the block copolymer-containing resin composition (A), the melt mass flow rate (MFR) measured under the conditions of 200 ° C. and 49 N load is 10 g / 10 minutes to 30 g / 10 minutes. If the MFR is less than 10 g / 10 minutes, the impact strength of the sheet and the container is lowered, which is not preferable. On the other hand, if the MFR exceeds 30 g / 10 minutes, the rigidity is lowered, which is not preferable. In particular, the MFR is preferably 15 g / 10 min to 25 g / 10 min, more preferably 15 g / 10 min to 23 g / 10 min, and even more preferably 16 g / 10 min to 23 g / 10 min.

In the block copolymer-containing resin composition (A), the proportion of conjugated diene in the entire block copolymer-containing resin composition (A) is 19 to 33% by mass. If the content ratio of the conjugated diene is less than 19% by mass, the impact strength of the resin composition decreases, which is not preferable. On the other hand, when the content ratio of the conjugated diene exceeds 33% by mass, the rigidity and transparency are lowered, which is not preferable.

The conjugated diene content ratio (mass) can be calculated from the usage ratio and compounding ratio of the conjugated diene amount to the total monomer amount used in the synthesis. As a method for analyzing the conjugated diene content ratio (mass) in the resin composition from the resin composition in which the amount of the monomer used is unknown, for example, there are the following methods.
(1) Dissolve 0.1 g of the sample in 50 mL of chloroform.
(2) Add 25 mL of iodine monochloride / carbon tetrachloride solution, mix well, and leave in the dark for 1 hour.
(3) Add 75 mL of 2.5% potassium iodide solution and mix well.
(4) Add the 20% sodium thiosulfate / ethanol solution with sufficient stirring until the color of the solution becomes pale yellow.
(5) Add about 0.5 mL of 1% starch indicator and titrate again with 20% sodium thiosulfate / ethanol solution until colorless.
(6) After the titration is completed, the amount of sodium thiosulfate / ethanol solution consumed a [mL] is measured.
In order to carry out the correction by measuring the blank, the operations (1) to (6) are also carried out on chloroform alone, and the consumed sodium thiosulfate / ethanol solution amount b [mL] is measured.
The content of conjugated diene can be calculated from the measured value according to the following formula.
Conjugated diene content (%) = [[{(ba) × 0.1 × c × 27} / 1000] / W] × 100
c: Titer of 20% sodium thiosulfate / ethanol solution W: Sample amount [g]

In the block copolymer-containing resin composition (A), the loss tangent (tan δ) obtained by dynamic viscoelasticity measurement is one maximum value (tan δ (max) value) in the temperature range of -100 ° C to -30 ° C. ), And the value obtained by dividing the tan δ value (tan δ (max + 30 ° C) value) at a temperature 30 ° C. higher than the maximum value temperature (tan δ peak temperature) by the maximum value (tan δ (max) value) is 0. It is 6.6 or more.
That is, (tan δ (max + 30 ° C.) value / tan δ (max) value) is 0.6 or more. (Tan δ (max + 30 ° C.) value / tan δ (max) value) is more preferably 0.65 or more, still more preferably 0.70 or more. Within this range, the impact resistance and transparency of the obtained low-temperature molded product can be improved in a more balanced manner without impairing other characteristics. In the present invention, there is no upper limit of the ratio of the above (tan δ (max + 30 ° C.) value / tan δ (max) value), and a larger ratio is preferable, but usually less than 1.

The tan δ peak temperature and (tan δ (max + 30 ° C.) value / tan δ (max) value) can be obtained from the dynamic viscoelasticity measurement (chart). Obtain the loss tangent (tan δ) from the measurement, set the tan δ maximum value in the temperature range of -100 ° C to -30 ° C as the "tan δ (max) value", set that temperature as the "tan δ peak temperature", and then use the tan δ peak temperature. The tan δ value at a temperature higher than 30 ° C. may be set as the “tan δ (max + 30 ° C.) value”, and (tan δ (max + 30 ° C.) value / tan δ (max) value) may be calculated.

In the dynamic viscoelasticity measurement, the storage elastic modulus (E') is measured by applying stress and strain in the tensile direction at a frequency of 1 Hz to the test sample and raising the temperature at a rate of 4 ° C./min using the following device. ), The loss elastic modulus (E ″), and the loss tangent (tan δ) can be measured (note that tan δ = E ″ / E ′). The sample of the resin composition for dynamic viscoelasticity measurement was held under pressure at 200 to 220 ° C. for 2 minutes by a heating press to relax the orientation, and then rapidly cooled to obtain 0. A 6 mm thick sheet is used. Then, it is stored and used for 24 hours or more in a room adjusted to a temperature of 23 ° C. and a relative humidity of 50% RH.
Dynamic viscoelasticity measuring device: RSA3 manufactured by TA Instruments Co., Ltd.,
Set temperature range: -120 to 130 ° C, set temperature rise rate: 4 ° C / min,
Measurement frequency: 1Hz

In the block copolymer-containing resin composition (A), the block ratio of vinyl aromatic hydrocarbons in the resin composition is preferably 85 to 100% by mass. If the block ratio is less than 85% by mass, the impact strength is lowered, which is not preferable. In particular, the block ratio is more preferably 90 to 100% by mass. The upper limit of the block rate is 100% by mass and does not exceed this.

Here, the block ratio of the vinyl aromatic hydrocarbon is the mass ratio of the polyvinyl aromatic hydrocarbon block in the block copolymer, and is obtained as follows.
"Block rate of vinyl aromatic hydrocarbons" (mass%)
= (Mass of vinyl aromatic hydrocarbons present as block-shaped homopolymerized segments in the copolymer / Mass of vinyl aromatic hydrocarbons contained in the copolymer) × 100

In the block copolymer-containing resin composition (A), the molecular weight distribution obtained by gel permeation chromatography (GPC) measurement, that is, the weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.1 to 3. It is preferably 5. Further, Mw / Mn is preferably 1.1 to 2.5. When Mw / Mn is in the above range, the impact resistance of the obtained low-temperature molded product can be improved in a more balanced manner without impairing other characteristics.

(Manufacturing method of block copolymer)
The production of the block copolymer constituting the block copolymer-containing resin composition (A) will be described. Block copolymers can be produced by anionic polymerization of vinyl aromatic hydrocarbon and conjugated diene monomers using an organolithium compound as a polymerization initiator in an organic solvent. Organic solvents include aliphatic hydrocarbons such as butane, pentane, hexane, isopentane, heptane, octane, and isooctane, alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane, or ethylbenzene and xylene. Aromatic hydrocarbons such as, etc. can be used. Cyclohexane is preferable as the organic solvent in terms of the solubility of the block copolymer.

An organic lithium compound is a compound in which one or more lithium atoms are bonded in a molecule, such as ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, and tert-butyl lithium. A monofunctional organic lithium compound, a polyfunctional organic lithium compound such as hexamethylenedilithium, butadienyldilithium, isoprenyldilithium and the like can be used.

As the vinyl aromatic hydrocarbon and the conjugated diene, those described above can be used, and one or more of them can be selected and used for polymerization, respectively. Then, in the living anionic polymerization using the above-mentioned organic lithium compound as a polymerization initiator, almost all of the vinyl aromatic hydrocarbons and conjugated diene subjected to the polymerization reaction are converted into a polymer.

The molecular weight of the block copolymer can be controlled by the amount of the polymerization initiator added relative to the total amount of the monomer added. In addition, the block ratio of vinyl aromatic hydrocarbons is the supply rate of vinyl aromatic hydrocarbons and conjugated diene when polymerizing vinyl aromatic hydrocarbons and conjugated diene to prepare block copolymers, and the addition of randomizing agents. It can be controlled by the amount.

The randomizing agent is a compound that acts as a Lewis base in the reaction, and amines, ethers, thioethers, phosphoramides, alkylbenzene sulfonates, and alkoxides of potassium or sodium can be used. Examples of amines include tertiary amines such as trimethylamine, triethylamine and tetramethylethylenediamine, and cyclic tertiary amines. Examples of ethers include dimethyl ether, diethyl ether, diphenyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, tetrahydrofuran (THF) and the like. In addition, triphenylphosphine, hexamethylphosphoramide, potassium alkylbenzene sulfonate or butoxides such as sodium alkylbenzene sulfonate, potassium and sodium can be mentioned. The randomizing agent is preferably tetrahydrofuran (THF).

The randomizing agent may be used alone or in combination of two or more. The addition concentration is preferably 0.001 to 10 parts by mass per 100 parts by mass of the monomer used as a raw material. The addition time may be before the start of the polymerization reaction or before the polymerization of the copolymer chain. Further, it can be additionally added as needed.

For the block copolymer, after all the monomers are added and the polymerization is completed, a coupling agent may be added to carry out the coupling. Coupling is a covalent bond between a living active site located at one end of a polymer chain and a reaction site in a coupling agent molecule, whereby two or more polymer chains are combined into one coupling agent molecule. It means to combine through. The coupling agent is a compound having two or more reaction sites per molecule that the living active site can attack.

The coupling agent is not limited, but is a chlorosilane compound such as dimethyldichlorosilane, silicon tetrachloride, 1,2-bis (methyldichlorosilyl) ester, and an alkoxysilane compound such as dimethyldimethoxysilane, tetramethoxysilane and tetraphenoxysilane. Examples thereof include compounds, tin tetrachloride, polyhalogenated hydrocarbons, carboxylic acid esters, polyvinyl compounds, epoxidized fats and oils such as epoxidized soybean oil and epoxidized flaxseed oil. Examples of the coupling agent include epoxidized fats and oils, and more preferably epoxidized soybean oil.

The coupling agent has a bifunctional coupling agent having two reaction sites per molecule, a trifunctional coupling agent having three reaction sites per molecule, or four reaction sites per molecule. A polyfunctional coupling agent such as a tetrafunctional coupling agent can also be used. Examples of the bifunctional coupling agent include dimethyldichlorosilane and dimethyldimethoxysilane. Examples of the trifunctional coupling agent include methyltrichlorosilane and methyltrimethoxysilane. Examples of the tetrafunctional coupling agent include tetrachlorosilane, tetramethoxysilane, tetraphenoxysilane and the like. Further, the epoxidized fat and oil has three ester groups per molecule, and has 0 to 3 epoxy groups per long chain alkyl group on the side of the three long chain alkyl groups, and thus is polyfunctional. It is a sex coupling agent.

The coupling agent may be used alone or in combination of two or more kinds of polyfunctional coupling agents. Further, one or more kinds of bifunctional coupling agents and one or more kinds of polyfunctional coupling agents can be used in combination. It is preferable to use one polyfunctional coupling agent alone.

The reaction sites that the living active site in the coupling agent can attack do not necessarily have to react completely, and some of them may remain unreacted. Furthermore, it is not necessary for all the polymer chains having all living active sites at one end to react with the reaction sites of the coupling agent, and the polymer chains remaining unreacted remain in the finally produced block copolymer. You may. Then, even if a block copolymer having a smaller number of branches than the number of branches expected when the reaction site of the coupling agent used completely reacts is mixed in the finally produced block copolymer. It does not matter, or a polymer chain in which only the coupling agent is bonded to one end, in which the coupling agent is simply replaced in the living active site, may be mixed in the final block copolymer. Rather, the final block copolymer has a block copolymer having a number of branches equal to the number of branches expected when the reaction site of the coupling agent used completely reacts, and the reaction site of the coupling agent used is completely. Block copolymers with fewer branches than expected during the reaction, polymer chains in which the coupling agent is simply replaced and bound to the living active site, and remain unreacted with the reaction sites of the coupling agent. It is preferable that any two or more of the polymer chains are mixed in order to obtain good molding processability.

The amount of the coupling agent added may be arbitrary, but is preferably set so that the reaction site of the coupling agent is present at 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 the reaction site are present with respect to the number of moles of the living active terminal present in the polymerization solution before the coupling step.

The block copolymer thus obtained can be inactivated by adding a polymerization inhibitor such as water, alcohol, or carbon dioxide in an amount sufficient to inactivate the active terminal. As a method for recovering the copolymer from the organic solvent solution of the obtained block copolymer, a method of precipitating with a poor solvent such as methanol, a method of evaporating the solvent with a heating roll or the like to precipitate the solvent (drum dryer method), A method of concentrating the solution with a concentrator and then removing the solvent with a vent-type extruder, a method of dispersing the solution in water, blowing steam to remove the solvent by heating, and recovering the copolymer (steam stripping method), etc. , Any method can be adopted.

<Polystyrene (B)>
As polystyrene (B) (hereinafter, may be referred to as “GPPS (B)”), general-purpose polystyrene (GPPS) produced by general radical polymerization can be used, and a known method can be used as the polymerization method. Can be manufactured. As the styrene-based monomer, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene and the like can be used alone or as a mixture, and styrene is preferable. Further, a monomer copolymerizable with these styrene-based monomers, for example, a monomer such as acrylonitrile, methacrylic acid ester, methacrylic acid, and acrylic acid ester can also be copolymerized as long as the effect of the present invention is not impaired. .. For example, "Toyo Styrene GP" manufactured by Toyo Styrene, "Styroltion PS" manufactured by Ineos Styroltion, "KUMHO GPPS" manufactured by KUMHO PETROCHEMICAL, "PSJ-polystyrene GPPS" manufactured by PS Japan, and the like can be mentioned.

GPPS (B) has a peak top molecular weight (Mp) of 230,000 to 400,000 obtained by gel permeation chromatography (GPC). When the peak top molecular weight (Mp) of GPPS is less than 230,000 and when it exceeds 400,000, the impact resistance is lowered. In particular, the peak top molecular weight (Mp) is preferably 260,000 to 370,000.

GPPS (B) preferably has a molecular weight distribution obtained by gel permeation chromatography (GPC), that is, a weight average molecular weight (Mw) / number average molecular weight (Mn) of 1.9 to 2.4. When Mw / Mn is 1.9 or more, deterioration of molding processability can be further suppressed. When Mw / Mn is 2.4 or less, the decrease in impact resistance can be further suppressed.

In GPPS (B), the total amount of the residual styrene monomer and the polymerization solvent is preferably 700 μg / g or less. When the total amount of the residual styrene monomer and the polymerization solvent exceeds 700 μg / g, the residual styrene monomer and the polymerization solvent volatilize during the molding process and when extruded from the die, aggregate on the die and adhere to the low temperature molded body, and the appearance. It may be defective or defective. In order to prevent the above phenomenon, it is effective to reduce the residual styrene monomer and the polymerization solvent as much as possible. In particular, the total amount of the residual styrene monomer and the polymerization solvent is more preferably 500 μg / g or less.

For the amount of residual styrene monomer and polymerization solvent in GPPS (B), 500 mg of general-purpose polystyrene (GPPS) was dissolved in 10 mL of N, N-dimethylformamide (DMF) containing cyclopentanol as an internal standard substance, and gas chromatography was performed. Can be measured under the following conditions using.
Gas chromatography: HP-5890 (manufactured by Hewlett-Packard)
Column: HP-WAX (manufactured by Hewlett-Packard, 0.25 mm x 30 m, film thickness 0.5 μm)
Injection temperature: 220 ° C
Column temperature: 60 ° C to 150 ° C, 10 ° C / min
Detector temperature: 220 ° C
Split ratio: 30/1

<Rubber-modified vinyl aromatic hydrocarbon polymer (C)>
A rubber-modified vinyl aromatic hydrocarbon polymer (C) obtained by graft-polymerizing a conjugated diene rubber-like polymer with a vinyl aromatic hydrocarbon (hereinafter referred to as "HIPS (C), High Impact Polymer (C)"). (May be shown.) Is obtained by graft-polymerizing a styrene-based monomer in the presence of a polyconjugated diene, and is known as a polymerization method, for example, a massive polymerization method, a massive / suspended compound. It can be produced by a step polymerization method, a solution polymerization method, or the like. Examples of the styrene-based monomer include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene and the like alone or in combination, and styrene is preferable. Further, a monomer copolymerizable with these styrene-based monomers, for example, a monomer such as acrylonitrile, methacrylic acid ester, methacrylic acid, and acrylic acid ester, can be copolymerized as long as the effect of the present invention is not impaired. can do. For example, "Toyo Styrene HI" manufactured by Toyo Styrene Co., Ltd., "Styroltion PS" manufactured by Ineos Styrene Co., Ltd., "PSJ-Polystyrene HIPS" manufactured by PS Japan, and the like can be mentioned.

The polyconjugated diene used for HIPS (C) includes high-cis polybutadiene having a 1,4-cis structure of 90 mol% or more and a 1,2-vinyl structure of 4 mol% or less, and 65 to 65 to a 1,4-cis structure. Either 95 mol%, high cis-high vinyl polybutadiene having a 1,2-vinyl structure of 4 to 30 mol%, low cis polybutadiene having a 1,4-cis structure of 15 to 40 mol%, or a styrene-butadiene block copolymer. May be used, or may be a mixture. Particularly preferably, it is locis polybutadiene, and when locis polybutadiene is used, a decrease in impact resistance can be further suppressed.

The volume median particle size of the rubber-like dispersed particles of HIPS (C) is 1 to 4 μm, preferably 1.4 to 4.0 μm, more preferably 2.0 to 4.0 μm, and particularly preferably. Is 2.5 to 4.0 μm. When the volume medium particle size is less than 1 μm and exceeds 4 μm, the impact resistance is lowered.

Examples of the method of adjusting the particle size include a method of adjusting the stirring speed of the rubber particles in the phase inversion region in the polymerization step, a method of adjusting the amount of the chain transfer agent in the raw material liquid, and the like.

As the volume median particle size of the rubber-like dispersed particles of HIPS (C), for example, a rubber-modified styrene resin is dissolved in an electrolytic solution (3% tetra-n-butylammonium / 97% dimethylformamide solution) and coulter mulch is used. The 50% by volume particle size of the volume-based particle size distribution curve measured by the sizer method (Multisizer II manufactured by Coulter; aperture diameter of aperture tube: 30 μm) is used.

The gel content of the rubber-like dispersed particles of HIPS (C) is 12 to 20% by mass, preferably 15 to 20% by mass, more preferably 17 to 20% by mass, and particularly preferably 17 to 19% by mass. %. When the gel content is less than 12% by mass and more than 20% by mass, the impact resistance is lowered.

Examples of the method for adjusting the gel content include a method for adjusting the rubber content in the polymerization step, a method for adjusting the amount of the initiator, and a method for adjusting the gel content by blending with a homopolymer of styrene after polymerization. The gel content is the ratio of rubber-like dispersed particles in HIPS (C), and is calculated by the following procedure. A rubber-modified styrene resin having a mass of 1.00 g is precisely weighed (W), and 35 mL of a 50% methyl ethyl ketone / 50% acetone mixed solution is added and dissolved, and the solution is dissolved by a centrifuge (Kokusan H-2000B (rotor: rotor:). In H)), the insoluble matter is precipitated by centrifugation at 10,000 rpm for 30 minutes, and the supernatant is removed by decantation to obtain the insoluble matter. The insoluble matter was pre-dried in a safety oven at 90 ° C. for 2 hours, further dried under reduced pressure in a vacuum dryer at 120 ° C. for 1 hour, cooled in a desiccator for 20 minutes, and then the mass (G) of the dried insoluble matter. Is measured and calculated from the following formula.
Gel content (amount of rubber-like dispersed particles) (mass%) = (G / W) x 100

The HIPS (C) preferably has a molecular weight distribution obtained by gel permeation chromatography (GPC), that is, a weight average molecular weight (Mw) / number average molecular weight (Mn) of 2.3 to 2.6. When Mw / Mn is 2.3 or more and 2.6 or less, the decrease in impact resistance can be further suppressed.

<Combined composition of (A) / (B) / (C)>
The content ratio of the block copolymer-containing resin composition (A), GPPS (B), and HIPS (C) is 100% by mass based on the total amount of the block copolymer-containing resin composition (A) and GPPS (B). Therefore, it is necessary that (A) / (B) = 30/70 to 85/15 (mass ratio). If the content of (A) is less than 30% by mass and the content of (B) exceeds 70% by mass, the impact strength is lowered, which is not preferable. On the other hand, when the content ratio of (B) is less than 15% by mass and the content ratio of (A) exceeds 85% by mass, the rigidity is lowered, which is not preferable. The content ratio (mass ratio) of (A) / (B) is preferably 25/75 to 70/30, and particularly preferably 40/60 to 60/40.

The content ratio of HIPS (C) needs to be 0.3 to 7 parts by mass with respect to 100 parts by mass of the total amount of the block copolymer-containing resin composition (A) and GPPS (B). If the content ratio of (C) is less than 0.3 parts by mass, the impact strength is lowered, which is not preferable. On the other hand, when the content ratio of (C) exceeds 7 parts by mass, the transparency is lowered, which is not preferable. In particular, the content ratio of (C) is preferably 1 to 7 parts by mass, preferably 1.5 to 5.0 parts by mass, based on 100 parts by mass of the total amount of the block copolymer-containing resin composition (A) and GPPS (B). Parts by mass are particularly preferred.

<Additives>
The resin composition can further contain various additives, if necessary. That is, a rubber-modified vinyl aromatic hydrocarbon-based weight obtained by graft-polymerizing a vinyl aromatic hydrocarbon on the block copolymer-containing resin composition (A), polystyrene (B), and conjugated diene rubber-like polymer. When producing a resin composition containing the coalesced (C), when undergoing various heat treatments during molding processing into sheets and containers, and when the low-temperature polymer is used in an oxidizing atmosphere or under irradiation with ultraviolet rays, etc. In order to deal with the deterioration of physical properties, or to further impart physical properties suitable for the purpose of use, for example, stabilizers, lubricants, processing aids, blocking inhibitors, antistatic agents, and antistatic agents. Additives such as clouding agents, weather resistance improvers, softeners, plasticizers, pigments, mineral oils, fillers, flame retardants, colorants, pigments, deodorants and the like can be added.

Stabilizers include, for example, 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-methylphenylacrylate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6- Phenol antioxidants such as di-tert-butyl-4-methylphenol, 2,2-methylenebis (4,6-di-tert-butylphenyl) octylphosphite, trisnonylphenylphosphite, bis (2,6) Examples thereof include phosphorus-based antioxidants such as −di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphofite.

Lubricants, processing aids, blocking inhibitors, antistatic agents, antifogging agents include saturated fatty acids such as palmitic acid, stearic acid and behenic acid, fatty acid esters such as octyl palmitate and octyl stearate, and pentaerythritol fatty acid esters. Furthermore, fatty acid amides such as erucic acid amide, oleic acid amide, stearic acid amide, and behenic acid amide, ethylene bisstearic acid amide, glycerin-mono-fatty acid ester, glycerin-di-fatty acid ester, and sorbitan-mono-palmitin. Examples thereof include acid esters, sorbitan fatty acid esters such as sorbitan-mono-stearic acid esters, and higher alcohols typified by myristyl alcohols, cetyl alcohols, and stearyl alcohols.

Examples of the weather resistance improver include benzotriazoles such as 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole and 2,4-di-tert-butylphenyl. Salicylate-based agents such as -3', 5'-di-tert-butyl-4'-hydroxybenzoate, benzophenone-based 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. Further, liquid paraffin, silicone oil, microcrystalline wax and the like can be added.

It is desirable that these additives are used in the resin composition of the present invention in an amount of preferably 7% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

Each component in the case of obtaining the block copolymer-containing resin composition (A), GPPS (B), and HIPS (C), in the case of mixing (A) to (C), and in the case of further mixing additives. The mixing method is not particularly limited. For example, it may be dry-blended with a Henschel mixer, a ribbon blender, a V-blender, or the like, or it may be melted and pelletized with an extruder. Alternatively, each polymer may be added at the stage of production, before the start of polymerization, during the polymerization reaction, after-treatment of the polymer, or the like.

<Low temperature molded product>
The low-temperature molded product can be produced by any conventionally known molding processing method. For example, the above resin composition can be obtained by extrusion molding, injection molding, hollow molding, or compression molding. That is, the low-temperature molded product is an extremely wide variety of practically useful products such as extrusion-molded products, injection-molded products, hollow-molded products, pneumatic molded products, vacuum-formed products, and biaxial stretch-molded products of various shapes. be able to. Further, these molding processing methods may be combined as in the primary processing, the secondary processing, and the tertiary processing.

The absolute value | ΔNxy | of the birefringence of the low-temperature molded product ^{is preferably 8.0 × 10 -4} or less. When | ΔNxy | is 8.0 × 10 ^-4 or less, the decrease in impact resistance can be further suppressed. Birefringence is performed by in-plane phase difference measurement using a phase difference measuring device with a standard measurement method in which the center of inclination is the slow axis and the angle θ between the polarizing plate transmission axis and the slow axis of the sample is 30 °. , Birefringence ΔNxy can be measured and obtained as its absolute value | ΔNxy |.

Birefringence is due to the structure of the monomer units, but in the bulk state of a completely amorphous polymer, the structural units are randomly arranged, so it is macroscopically isotropic and does not show birefringence. .. However, since a general plastic material is commercialized through molding, a shearing force is applied at the shaping stage, flow orientation occurs, and birefringence occurs.
On the other hand, when the molecules are oriented in the flow direction (MD, Machine Direction) due to the flow orientation, the intensity in the flow direction (MD) increases, but the intensity in the direction perpendicular to the MD (TD, Transfer Direction) is small. As a result, strength anisotropy occurs. This is probably because the entropy is small and unstable when the molecules are oriented, so energy (molecular orientation energy) that tries to return to the random state is generated in order to alleviate the anisotropy. Since MD is in a direction parallel to the molecular orientation energy, that is, in the same direction, it is considered that when an impact is applied, the molecular orientation energy acts in a direction of relaxing (canceling) the impact energy and improving the strength. On the other hand, since TD is in the direction perpendicular to the molecular orientation energy, it is considered that when an impact is applied, the molecular orientation energy acts in the direction of increasing (adding) the impact energy, and the strength decreases. That is, it is considered that there is a correlation between birefringence and anisotropy of intensity.
When an impact is applied to a low-temperature molded body having a large birefringence, that is, a large anisotropy of strength, the impact energy is applied evenly regardless of MD / TD, so that cracks occur in the direction of low strength. It will be easier. As a result, it is considered that the strength of the low-temperature molded product as a whole decreases. That is, it is considered that the lower the birefringence and the closer it is to zero, the more the anisotropy of the strength can be suppressed, and the stronger the strength of the low-temperature molded product as a whole is improved.

In the low temperature molded body, the flow direction (MD) is the flow orientation, that is, the orientation direction of the molecules, and since the styrene resin is used, the birefringence has a negative value. Birefringence represents the degree of MD molecular orientation during sheet molding.

Birefringence can be controlled by adjusting the molding processing conditions, but it can also be controlled by the melt mass flow rate (MFR) of the block copolymer-containing resin composition (A) used in the low-temperature molded product. By using the highly fluid block copolymer-containing resin composition (A), it is possible to control birefringence without adjusting the processing conditions by making the material at the time of molding highly fluid. Become.

Birefringence can be measured using a phase difference measuring device "KOBRA-WR" (manufactured by Oji Measuring Instruments Co., Ltd.) or the like. The birefringence ΔNxy was measured by the in-plane phase difference measurement by the standard measurement method when the angle θ between the polarization central axis is the slow axis and the polarizing plate transmission axis and the slow axis of the sample is 30 °, and the number of tests is 10 times. Medium, the average value excluding obvious abnormal values is used. The theoretical value of calculation is used as the refractive index ND of the sample required for the measurement. It is also necessary to confirm that the sign of birefringence is negative by observing with a phase contrast microscope. By these measurements, the degree of MD molecular orientation at the time of sheet molding can be confirmed.

<Use>
The low temperature molded product can be a sheet and a container. That is, a polystyrene-based sheet suitable for producing a container and a container made of the sheet can be used. The sheet and container have excellent impact resistance and transparency. The sheet and container may be non-foamed or foamed. The shapes of the sheet and the container are not particularly limited, and various shapes can be adopted depending on the application. For example, a lunch container, a fitting container, a platter, a plate, a tray, a bowl, a cup, a lid, a cutting board, a pencil case, an underlay, a clear file, a clear case, and the like can be mentioned.

The thickness of the sheet and the container is not particularly limited, and various thicknesses can be taken depending on the application. The general thickness is preferably 0.05 to 5 mm. By setting the thickness to 0.05 mm or more, the rigidity of the sheet and the container can be maintained. On the other hand, by setting the thickness to 5 mm or less, the molding process can be easily performed. In particular, the thickness is preferably 0.1 to 1.5 mm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the interpretation of the present invention is not limited by these Examples.

<Polymerization example 1>
Block copolymers of styrene and 1,3-butadiene were produced by the following operations (1) to (12).
(1) 500.0 kg of cyclohexane and 75.0 g of tetrahydrofuran (THF) were placed in the reaction vessel.
(2) 1,060 mL of a 10 mass% cyclohexane solution of n-butyllithium was added thereto as a polymerization initiator solution, and the temperature was maintained at 30 ° C.
(3) 10.0 kg of styrene was added, the internal temperature was raised to 80 ° C., and styrene was anionically polymerized.
(4) After the styrene is completely consumed, while maintaining the internal temperature of the reaction system at 80 ° C., a total amount of 2.0 kg of styrene and a total amount of 8.0 kg of 1,3-butadiene are added at 25.0 kg / h, respectively. (Time) Both were added simultaneously at a constant addition rate of 100.0 kg / h.
(5) After the styrene and 1,3-butadiene were completely consumed, 4.8 kg of styrene was added while maintaining the internal temperature of the reaction system at 80 ° C., and the styrene was anionic polymerized.
(6) After the styrene is completely consumed, while maintaining the internal temperature of the reaction system at 80 ° C., a total amount of 2.0 kg of styrene and a total amount of 8.0 kg of 1,3-butadiene are added at 25.0 kg / h, respectively. Both were added simultaneously at a constant addition rate of 100.0 kg / h.
(7) After the styrene and 1,3-butadiene were completely consumed, 4.8 kg of styrene was added while maintaining the internal temperature of the reaction system at 80 ° C., and the styrene was anionic polymerized.
(8) After the styrene is completely consumed, while maintaining the internal temperature of the reaction system at 80 ° C., a total amount of 2.0 kg of styrene and a total amount of 8.0 kg of 1,3-butadiene are added at 25.0 kg / h, respectively. Both were added simultaneously at a constant addition rate of 100.0 kg / h.
(9) After the styrene and 1,3-butadiene were completely consumed, the internal temperature of the reaction system was lowered to 55 ° C., 75.2 kg of styrene was added, and the styrene was anionic polymerized. The internal temperature rose to 90 ° C.
(10) After the styrene was completely consumed, the internal temperature of the reaction system was lowered to 55 ° C., and 75.2 kg of styrene was added all at once to complete the polymerization.
(11) Finally, all the polymerization active terminals are deactivated with water to prepare a polymerization solution containing a polymer _{having an S- (RS) 2-RS structure having a polystyrene block and a random block of styrene and butadiene.} Obtained. (In the above general formula, S represents a polystyrene block, and R represents a random block of styrene and butadiene.)
(12) This polymer solution was devolatile to obtain a block copolymer of Polymerization Example 1. The peak top molecular weight (Mp) was 221,000 and Mw / Mn was 1.04. Table 1 shows the main points of the above polymerization example 1.

<Polymerization Examples 2-8>
In the above polymerization example 1, the composition of the block copolymer can be determined by adjusting the amount of the monomers used in the above (3) to (10), and the n-butyllithium used in the above (2) can be determined. The molecular weight can be determined by adjusting the amount. Therefore, block copolymers of Polymerization Examples 2 to 8 were obtained by carrying out the same procedure as in Polymerization Example 1 except for the conditions shown in Table 1 below. The main points of the above polymerization examples 2 to 8 are summarized in Table 1.

<Polymerization example 9>
Block copolymers of styrene and 1,3-butadiene were produced by the following operations (1) to (11).
(1) 500.0 kg of cyclohexane and 75.0 g of THF were placed in the reaction vessel.
(2) 2,030 mL of a 10 mass% cyclohexane solution of n-butyllithium was added thereto as a polymerization initiator solution, and the temperature was maintained at 30 ° C.
(3) 10.0 kg of styrene was added, the internal temperature was raised to 80 ° C., and styrene was anionically polymerized.
(4) After the styrene is completely consumed, a total amount of 4.7 kg of styrene and a total amount of 18.7 kg of 1,3-butadiene are added at 25.0 kg / h, respectively, while maintaining the internal temperature of the reaction system at 80 ° C. Both were added simultaneously at a constant addition rate of 100.0 kg / h.
(5) After the styrene and 1,3-butadiene were completely consumed, 5.0 kg of styrene was added while maintaining the internal temperature of the reaction system at 80 ° C., and the styrene was anionic polymerized.
(6) After the styrene is completely consumed, a total amount of 4.6 kg of styrene and a total amount of 18.6 kg of 1,3-butadiene are added at 25.0 kg / h, respectively, while maintaining the internal temperature of the reaction system at 80 ° C. Both were added simultaneously at a constant addition rate of 100.0 kg / h.
(7) After the styrene and 1,3-butadiene were completely consumed, 5.0 kg of styrene was added while maintaining the internal temperature of the reaction system at 80 ° C., and the styrene was anionic polymerized.
(8) After the styrene is completely consumed, a total amount of 4.7 kg of styrene and a total amount of 18.7 kg of 1,3-butadiene are added at 25.0 kg / h, respectively, while maintaining the internal temperature of the reaction system at 80 ° C. Both were added simultaneously at a constant addition rate of 100.0 kg / h.
(9) After the styrene and 1,3-butadiene were completely consumed, the internal temperature of the reaction system was lowered to 50 ° C., and 110.0 kg of styrene was added all at once to complete the polymerization.
(10) Finally, all the polymerization active terminals are deactivated with water to prepare a polymerization solution containing a polymer _{having an S- (RS) 2-RS structure having a polystyrene block and a random block of styrene and butadiene.} Obtained.
(11) This polymer solution was devolatile to obtain a block copolymer of Polymerization Example 9. The peak top molecular weight (Mp) was 121,000 and Mw / Mn was 1.02. Table 2 shows the main points of the above polymerization example 9.

<Polymerization Examples 10 to 16>
In the above polymerization example 9, the composition of the block copolymer can be determined by adjusting the amount of the monomers used in the above (3) to (9), and n-butyllithium used in the above (2). The molecular weight can be determined by adjusting the amount. Therefore, block copolymers of Polymerization Examples 10 to 16 were obtained by carrying out the same procedure as in Polymerization Example 9 except for the conditions shown in Table 2 below. Table 2 summarizes the main points of the above-mentioned polymerization examples 10 to 16.

<Polymerization example 17>
Block copolymers of styrene and 1,3-butadiene were produced by the following operations (1) to (6).
(1) 500.0 kg of cyclohexane and 75.0 g of THF were placed in the reaction vessel.
(2) 4,230 mL of a 10 mass% cyclohexane solution of n-butyllithium was added thereto as a polymerization initiator solution, and the temperature was maintained at 30 ° C.
(3) 44.0 kg of styrene was added, and styrene was anionically polymerized. The internal temperature rose to 45 ° C.
(4) After the styrene was completely consumed, the internal temperature of the reaction system was lowered to 40 ° C., and 90.0 kg of 1,3-butadiene and 66.0 kg of styrene were added at the same time to complete the polymerization. The internal temperature rose to 125 ° C.
(5) Finally, all the polymerization active terminals are deactivated with water to have a polystyrene block, a tapered block of styrene and butadiene, and an ST structure (in the formula, S represents a polystyrene block and T represents styrene and butadiene). A polymer solution containing a polymer of (representing a tapered block) was obtained.
(6) This polymer solution was devolatile to obtain a block copolymer of Polymerization Example 17. The peak top molecular weight (Mp) was 66,000 and Mw / Mn was 1.07. The main points of the polymerization example 17 are summarized in Table 3.

<Polymerization Example 18>
In the above polymerization example 17, the composition of the block copolymer can be determined by adjusting the amount of the monomers used in the above (3) and (4), and n-butyllithium used in the above (2). The molecular weight can be determined by adjusting the amount. Therefore, the block copolymer of Polymerization Example 18 was obtained by carrying out the same procedure as in Polymerization Example 17 except for the conditions shown in Table 3 below. The main points of the polymerization example 18 are summarized in Table 3.

<Formulation example>
<Formulation Examples 1 to 16>
The block copolymers obtained in Polymerization Examples 1 to 18 were mixed at the blending ratios shown in Table 4 to produce a block copolymer-containing resin composition. The block copolymer-containing resin composition is melt-kneaded using a single-screw extruder "HV-40-30" (manufactured by Tabata Machinery Co., Ltd., φ40 mm) at an extrusion temperature of 200 ° C. and a screw rotation speed of 100 rpm to form a strand. After extruding to, and after cooling, pelletized with a pelletizer. Tables show the melt mass flow rate (MFR), the conjugated diene-containing mass ratio, the tan δ peak temperature, and (tan δ (max + 30 ° C.) value) / (tan δ (max) value) of the block copolymer-containing resin compositions in Formulation Examples 1 to 16. It is shown collectively in 4.

<Measurement of molecular weight and dispersion Mw / Mn>
Using a gel permeation chromatograph (GPC), the weight average molecular weight Mw, the number average molecular weight Mn, and the peak top molecular weight (Mp) were measured. In the present specification, unless otherwise specified, the molecular weight is the peak top molecular weight (Mp), and when coupling is performed, it is Mp before coupling. The degree of dispersion is weight average molecular weight (Mw) / number average molecular weight (Mn), and when coupling is performed, it is Mw / Mn after coupling.
GPC device name: "HLC-8220 GPC" (manufactured by Tosoh Corporation)
Column used: 4 "Shodex GPCKF-404" (manufactured by Showa Denko) connected in series Column temperature: 40 ° C
Detection method: differential refractive index method, mobile phase: tetrahydrofuran,
Sample concentration: 2% by mass
Calibration curve: Standard polystyrene (manufactured by VARIAN, peak top molecular weight Mp = 2,560,000, 841,700, 280,500, 143,400, 63,350, 31,420,9,920,2,930) Created using.

<Measurement of melt mass flow rate (MFR)>
Using a fully automatic melt flow index tester "LABOT-MI" (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the melt mass flow rate (MFR) was measured under the conditions of 200 ° C. and 49 N load in accordance with JIS K7210 (ISO1133).

<Butadiene content ratio (mass) of resin composition>
The conjugated diene content ratio in the block copolymer and the block copolymer-containing resin composition was calculated from the usage ratio and blending ratio of the amount of 1,3-butadiene with respect to the total amount of the monomers used in the above polymerization example.

<Styrene block rate in resin composition>
¹ H-NMR was measured and calculated using nuclear magnetic resonance (NMR). Of the five protons added to the aromatic ring of polystyrene, the integrated peak intensity of 6.2 to 6.8 ppm, which is attributed as two protons added to the ortho position, is converted into five protons to block-shaped styrene. The amount was W.

Also, from the integral value of the peak intensity of 6.2-7.6 ppm, which includes the integral value of the peak intensity of 6.8 to 7.6 ppm assigned as the three protons added to the para position and the meta position, of the hydrocarbon. The value obtained by dividing the integrated value of the peak intensity was defined as the total amount of styrene (total amount of vinyl aromatic hydrocarbons) W0. The block ratio was calculated by substituting the W and W0 into the following definition formula. The block-shaped styrene amount (block-shaped vinyl aromatic hydrocarbon amount) W is a chain composed of 5 or more monomer units for the reason of the sensitivity of the device.

Styrene block rate (%) = (W / W0) x 100
Nuclear magnetic resonance device name: AVANCE-300 manufactured by Bruker Biospin
Measurement nuclide: ¹ H, resonance frequency: 300 MHz ( ¹ H), measurement solvent: CDCl ₃

<Tanδ peak temperature and (tanδ (max + 30 ° C) value / tanδ (max) value)>
Obtained from dynamic viscoelasticity measurement (chart). The loss tangent (tan δ) was obtained from the measurement, and the maximum value of the tan δ maximum values in the temperature range of −100 to −30 ° C. was defined as the “tan δ (max) value”, and the temperature was defined as the “tan δ peak temperature”. Next, the tan δ value at a temperature 30 ° C. higher than the tan δ peak temperature was defined as the “tan δ (max + 30 ° C.) value”, and (tan δ (max + 30 ° C.) value / tan δ (max) value) was calculated.

<Dynamic viscoelasticity measurement>
Using the following equipment, stress and strain in the tensile direction with a frequency of 1 Hz are applied to the test sample, and the storage elastic modulus (E') and loss elastic modulus (E ") are raised at a rate of 4 ° C./min. , And the loss tangent (tan δ) was measured (note that tan δ = E "/ E'). The sample of the resin composition for dynamic viscoelasticity measurement was held under pressure at 200 to 220 ° C. for 2 minutes by a heating press to relax the orientation, and then rapidly cooled to obtain 0. A 6 mm thick sheet was used. Then, it was stored and used for 24 hours or more in a room adjusted to a temperature of 23 ° C. and a relative humidity of 50% RH.
Dynamic viscoelasticity measuring device: RSA3 manufactured by TA Instruments Co., Ltd.,
Set temperature range: -120 to 130 ° C, set temperature rise rate: 4 ° C / min,
Measurement frequency: 1Hz

<Examples 1 to 27 and Comparative Examples 1 to 17>
(Preparation of sheet)
The block copolymer-containing resin composition (A), GPPS (B), and HIPS (C) were mixed at the blending ratios shown in Tables 5 and 6 to obtain a resin composition. Using this resin composition, a sheet was formed by the following procedure. Using a φ40 mm single-screw extruder "VS40-26" manufactured by Tanabe Plastics Co., Ltd. with a T-die with a width of 40 cm attached to the tip, the resin of the compounding example is used at an extrusion temperature of 200 ° C., a T-die temperature of 200 ° C., and a screw rotation speed of 60 rpm. A single-layer sheet having a sheet thickness of 0.6 mm was produced at a cooling roll temperature of 50 ° C. using a “480-inch seating device” manufactured by Tanabe Plastics Co., Ltd. The thickness of the sheet was adjusted by the lip opening of the die, and the take-up speed of the sheet was kept constant at 1.3 m / min. The resins used are shown in Tables 5 and 6.

For the GPPS (B) used, the peak top molecular weights Mp and Mw / Mn are summarized in Table 7.

Table 8 shows the peak top molecular weight Mp, Mw / Mn, the volume median particle size of the rubber-like dispersed particles, and the gel content of the HIPS (C) used.

(Making a container)
Using the sheet molded above, a container was molded. A container was formed by setting a mold for a parts tray with a depth of 19 mm in a "pressurized air vacuum forming machine for research and development" (manufactured by Asano Laboratories Co., Ltd.) and vacuum forming at 110 ° C. Both Examples and Comparative Examples could be molded without any problem. However, in the comparative example, as in the case of the sheet, insufficient strength and insufficient transparency occurred.

(Seat impact)
The measurement was performed using an "impact tester" (manufactured by Tester Sangyo Co., Ltd.) and a striking core having a tip diameter of 12.7 mm. Other measurement conditions were in accordance with ASTM D3420. If it does not punch through, it is described as ">4.5".

(DuPont impact strength)
Using the DuPont impact tester "H-100" (manufactured by Toyo Seiki Seisakusho Co., Ltd.), place 20 60 mm square test pieces cut out from the sheet on the cradle, and place a hammer with a tip diameter of 6.35 mm. It was placed on a test piece, a weight of 100 g was dropped on the upper end of the striking core, and the presence or absence of cracks generated in the sheet was visually inspected and converted into an energy value. Before the main measurement, another 2 to 3 preliminary test pieces are used to obtain the approximate height of the falling weight at which the sheet breaks, and the first piece is measured at the falling weight height determined from the result of the preliminary measurement. However, for the second and subsequent sheets, based on the measurement results immediately before, the height of the falling weight was increased by 5 cm when the sheet was not cracked, and the height of the dropped weight was decreased by 5 cm when the sheet was cracked, and the same measurement was performed. This operation was performed 20 times in succession, and the DuPont impact strength was determined by the formula shown below from the record of the height of the falling weight and the presence or absence of cracks in each time.
Total weight drop height with respect to X = A / number of A (m) A: Sheet without cracking Total weight drop height with respect to Y = B / number of B (m) B: Sheet with crack Z = (X + Y) / 2 (m)
DuPont impact strength (J) = 0.1 (kg) x 9.8 (m / s ² ) x Z (m)

(Measurement under 5 ° C and -20 ° C conditions)
"Impact tester" (manufactured by Tester Sangyo Co., Ltd.), DuPont impact tester "H-100" (manufactured by Toyo Seiki Seisakusho Co., Ltd.), measuring samples in a constant temperature and humidity chamber "TBE-3N1AD + HS" (manufactured by Tabei Espec) It was installed and the measurement was carried out after adjusting the room temperature to 5 ° C and -20 ° C.

(Tensile modulus)
Using the Tensilon universal tester "RTC-1210A" (manufactured by A & D Co., Ltd.), a dumbbell-type test piece conforming to JIS K6732 was cut from the sheet so that the MD was long, and the initial chuck interval was 50 mm and the tensile speed. The measurement was performed by pulling to the MD in an environment of 10 mm / min and 23 ° C., and the average of 7 tests was taken as the measured value.

(transparency)
The measurement was performed according to JIS K7136 using a turbidity meter "NDH2000" (manufactured by Nippon Denshoku Kogyo Co., Ltd.), and the HAZE value thereof was described.

As is clear from the comparison between Examples 1 to 7 and Comparative Example 1, when there are two types of block copolymers of vinyl aromatic hydrocarbons and conjugated diene, the Dupont impact strength, which is an index of the point impact strength, is maintained. However, when there was only one type of block copolymer of vinyl aromatic hydrocarbon and conjugated diene (Comparative Example 1), the Dupont impact strength, which is an index of the point impact strength, decreased.

As is clear from the comparison of Examples 1 to 7 and Comparative Examples 2 and 3, the melt mass flow rate (MFR) of the block copolymer-containing resin composition (A) measured under the conditions of 200 ° C. and 49 N load was determined. If it is less than 10 g / 10 minutes, the measured value of sheet impact at -20 ° C, which is an index of surface impact strength, and the Dupont impact strength, which is an index of point impact strength, decrease. The measured value of sheet impact at -20 ° C, which is an index of strength, decreased.

As is clear from the comparison of Examples 8 to 11 and Comparative Examples 4 and 5, when the content ratio of the conjugated diene in the entire block copolymer-containing resin composition (A) is less than 19% by mass, the surface impact The measured value of the sheet impact, which is an index of strength, and the dupont impact strength, which is an index of point impact strength, decreased, and when it exceeded 33% by mass, the rigidity and transparency decreased.

As is clear from the comparison between Example 11 and Comparative Example 6, when the tan δ (max + 30 ° C.) value / tan δ (max) value is less than 0.6, the measured value of the sheet impact, which is an index of the surface impact strength, and the measured value , DuPont impact strength, which is an index of point impact strength, decreased.

As is clear from the comparison of Examples 11 to 15 and Comparative Examples 7 and 8, when the peak top molecular weight (Mp) of GPPS (B) is less than 230,000, the measurement of sheet impact, which is an index of surface impact strength, is performed. The value and the DuPont impact strength, which is an index of the point impact strength, decreased, and when it exceeded 400,000, the DuPont impact strength, which is an index of the point impact strength, decreased.

As is clear from the comparison of Examples 3, 16 to 18 and Comparative Examples 9 and 10, when the volume median particle diameter of the rubber-like dispersed particles of HIPS (C) is less than 1 μm, it is an index of the point impact strength. When the DuPont impact strength decreased and exceeded 4 μm, the measured value of the sheet impact at −20 ° C., which is an index of the surface impact strength, decreased.

As is clear from the comparison of Examples 3, 16 to 18 and Comparative Examples 11 and 12, when the gel content of the rubber-like dispersed particles of HIPS (C) is less than 12% by mass, DuPont is an index of impact strength. When the impact strength decreased and exceeded 20% by mass, the measured value of the sheet impact, which is an index of the surface impact strength, and the DuPont impact strength, which is an index of the point impact strength at −20 ° C., decreased.

As is clear from the comparison of Examples 3, 11, 19 to 23, and Comparative Example 13, when HIPS (C) is contained, the impact strength can be maintained, but when it is not contained (Comparative Example 13). The measured value of the sheet impact, which is an index of the surface impact strength, and the DuPont impact strength, which is an index of the point impact strength at −20 ° C., decreased.

As is clear from the comparison of Examples 3, 11, 19 to 23, and Comparative Examples 14 and 15, HIPS (C) with respect to 100% by mass of the total amount of the block copolymer-containing resin composition (A) and GPPS (B). When the content ratio is less than 0.3% by mass, the measured value of sheet impact, which is an index of surface impact strength, and the dupon impact strength, which is an index of point impact strength at -20 ° C, decrease, and 7.0% by mass. If it exceeds, the transparency is reduced.

As is clear from the comparison of Examples 3, 24 to 27, and Comparative Examples 16 and 17, the content ratio of (A) to 100% by mass of the total amount of the block copolymer-containing resin composition (A) and GPPS (B). However, if it is less than 30% by mass and the content ratio of (B) exceeds 70% by mass, the measured value of sheet impact, which is an index of surface impact strength, and the Dupont impact strength, which is an index of point impact strength, decrease. When the content ratio of (A) exceeds 85% by mass and the content ratio of (B) is less than 15% by mass, the rigidity is lowered.

The low-temperature molded product of the present invention makes use of its excellent impact resistance, transparency, and mechanical properties, and there is no concern about cracking during the transfer or storage of refrigerated or frozen foods, and the contents can be visually recognized. It can be used as a packaging container or a beverage container, especially a container for ice confectionery, refrigerated food, and frozen food, and a lid. It can also be widely used as an industrial container or tray for transporting electronic parts, a daily miscellaneous goods packaging container, a blister pack, or the like.

Claims (6)

The content ratio of the following (A) and (B) to 100 parts by mass is (A) / (B) = 30/70 to 85/15 (mass ratio), and the total amount of the following (A) and (B). A resin composition in which the content ratio of the following (C) to 100 parts by mass is 0.3 to 7 parts by mass, and for producing a molded product capable of achieving high impact resistance under low temperature conditions. ..
(A); A block copolymer-containing resin composition of a vinyl aromatic hydrocarbon and a conjugated diene satisfying the following (a-1) to (a-4).
(A-1); The block copolymer (i) of a vinyl aromatic hydrocarbon and a conjugated diene satisfying the following (i-1) and the following (i-2), the following (ii-1) and the following (ii). It contains at least a block copolymer (ii) of a vinyl aromatic hydrocarbon satisfying -2) and a conjugated diene.
(I-1); In the gel permeation chromatogram, the peak top molecular weight (Mp) has at least one peak in the range of 105,000 to 250,000.
(I-2); The content ratio of conjugated diene is 10 to 20% by mass with respect to 100% by mass of the block copolymer (i).
(Ii-1); In the gel permeation chromatogram, the peak top molecular weight (Mp) has at least one peak in the range of 40,000 to 140,000.
(Ii-2); The content ratio of the conjugated diene is 27 to 60% by mass with respect to 100% by mass of the block copolymer (ii).
(A-2); The melt mass flow rate (MFR) measured under the conditions of 200 ° C. and 49 N load is 10 g / 10 minutes to 30 g / 10 minutes.
(A-3); The content ratio of conjugated diene in the total amount of 100% by mass of the block copolymer-containing resin composition (A) is 19 to 33% by mass.
(A-4); The loss tangent (tan δ) obtained by dynamic viscoelasticity measurement has one maximum value (tan δ (max) value) in the temperature range of -100 to -30 ° C, and the temperature of the maximum value. The value obtained by dividing the tan δ value (tan δ (max + 30 ° C.) value) when the temperature is 30 ° C. higher than (tan δ peak temperature) by the maximum value (tan δ (max) value) is 0.6 or more.
(B); Polystyrene satisfying the following (b-1).
(B-1); The peak top molecular weight (Mp) obtained by gel permeation chromatography (GPC) is 230,000 to 400,000.
(C); A rubber-modified vinyl aromatic hydrocarbon-based polymer obtained by graft-polymerizing a vinyl aromatic hydrocarbon onto a conjugated diene-based rubber-like polymer that satisfies the following (c-1) and (c-2).
(C-1); The volume-medium particle size of the rubber-like dispersed particles is 1 to 4 μm.
(C-2); The gel content of the rubber-like dispersed particles is 12 to 20% by mass. The block copolymer-containing resin composition (A) satisfies the following (a-5) and (a-6), and polystyrene (B) satisfies the following (b-2). The resin composition according to claim 1, wherein the coalescence (C) satisfies the following (c-3).
Block copolymer-containing resin composition (A)
(A-5); The block ratio of vinyl aromatic hydrocarbons in the block copolymer-containing resin composition (A) is 85 to 100% by mass.
(A-6); Mw / Mn obtained by gel permeation chromatography (GPC) is 1.1 to 3.5 (where Mw: weight average molecular weight, Mn: number average molecular weight).
Polystyrene (B)
(B-2); Mw / Mn obtained by gel permeation chromatography (GPC) is 1.9 to 2.4 (where Mw: weight average molecular weight, Mn: number average molecular weight).
Rubber-modified vinyl aromatic hydrocarbon-based polymer (C)
(C-3); Mw / Mn obtained by gel permeation chromatography (GPC) is 2.3 to 2.6 (however, Mw: weight average molecular weight, Mn: number average molecular weight). The resin composition according to claim 1 or 2 , wherein the block copolymers (i) and (ii) satisfy (i) / (ii) = 15/85 to 60/40 (mass ratio). The vinyl aromatic hydrocarbon is styrene, the resin composition according to any one of claim 1 to 3, wherein said conjugated diene is 1,3-butadiene. A molded product that can achieve high impact resistance under low temperature conditions, which is obtained by molding the resin composition according to any one of claims 1 to 4. A molded product that is a sheet or container and can achieve high impact resistance under the low temperature conditions according to claim 5.