JP2024059224A - AS-based resin composition and molded body - Google Patents

Abstract

[Problem] To obtain an AS-based resin composition and molded article having a desired bio-based degree and without impairing the excellent mechanical properties inherent to AS-based resin. [Solution] An AS-based resin composition containing an AS-based resin (a), a bio-based polyethylene (b), and a hydrogenated block copolymer (c), wherein the hydrogenated block copolymer (c) has a polymer block S mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units, 50 mol % or more of the conjugated diene portion constituting the hydrogenated block copolymer (c) is hydrogenated, the mass ratio of the AS-based resin (a) to the bio-based polyethylene (b) is (a)/(b) = 99/1 to 50/50, and the mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) is (b)/(c) = 90/10 to 50/50. [Selected Figure] None

Description

The present invention relates to an AS-based resin composition and a molded article.

In general, vinyl aromatic resins, such as polystyrene resin, AS resin (acrylonitrile/styrene copolymer), and ABS resin (acrylonitrile/butadiene/styrene copolymer), are excellent in moldability, rigidity, impact resistance, etc., and are inexpensive and have a low specific gravity, making them economical. Therefore, they are widely used in various fields as materials for injection molded products, sheets and films extruded from T-dies, and round or square tubular irregular extrusion products extruded from irregular shaped dies.

In recent years, with growing awareness of global environmental issues, there has been a growing momentum to reduce the amount of plastic used and switch to materials that do not rely on fossil resources, and such efforts are spreading to a variety of fields and applications.

Among the vinyl aromatic resins mentioned above, AS-based resins, which have an excellent balance of transparency, surface hardness (resistance to scratches), rigidity, chemical resistance, etc., are widely used mainly in injection molded products such as home appliances, office automation equipment parts, cosmetic containers, daily necessities, stationery, etc. In these applications, the required level of mechanical properties is high, and at the current technological level, the AS-based resins widely used in home appliances, cosmetic containers, automobile parts, etc. have not yet been made available widely from an economic and industrial perspective. Furthermore, there are still many technical issues to be resolved in order to produce AS-based resins from non-fossil raw material monomers, and the reality is that stable industrial production and practical application have not yet been achieved, and the immediate challenge is to make AS-based resins non-fossil raw materials.

The AS-based resins currently being consumed and distributed on the market are essentially fossil resource-based materials that are made from fossil resources. When they are incinerated as plastic waste after use, carbon dioxide is newly released into the atmosphere, which is one of the factors that contribute to global warming and the abnormal weather that accompanies it. For this reason, there is growing momentum each year to reduce the consumption of fossil resource-based plastic materials.

In response to the growing awareness of environmental issues in recent years, biopolymers made from plant-derived monomers, such as polyethylene made from plant-derived monomers, have come into the spotlight as carbon-neutral materials to reduce the use of fossil fuel resources, and are increasingly being used in plastic shopping bags, cutlery, and other applications (see, for example, Patent Documents 1 and 2).

Japanese Patent No. 5453098 Patent No. 5799520

As described above, AS-based resins have an excellent balance of transparency, surface hardness (resistance to scratches), rigidity, chemical resistance, etc., are inexpensive, have a relatively low specific gravity, and are therefore economically excellent, and are therefore widely used in various fields as various molded products. On the other hand, polyethylene using plant-derived monomers has been used in various applications for the purpose of reducing the use of fossil resources, and if plant-derived polyethylene could be blended with AS-based resins, it could help reduce the consumption of fossil resources.
However, AS-based resins and polyethylene are completely incompatible, and when they are blended together, the mechanical properties inherent to AS-based resins are significantly impaired. As a result, the resins are far from being of a practical standard for use in home appliances, cosmetic containers, and automobile parts. To date, no such research and development has been carried out in the industrial sector.

In view of the problems with the conventional technology described above, the present invention aims to provide an AS-based resin composition that has a certain degree of bio-based content and excellent balance of mechanical properties, and a molded article made from the same, by combining an AS-based resin made from fossil-based raw materials as the starting monomer with bio-based polyethylene made from plant-derived bio-based raw materials as the starting monomer, and taking measures to make the two compatible.

As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, they have succeeded in achieving excellent mechanical properties that could not be achieved with a resin composition consisting only of AS-based resin and bio-based polyethylene by further combining an acrylonitrile/styrene copolymer, a so-called AS-based resin, with bio-based polyethylene, and have found that this solves the above-mentioned problems of the conventional techniques, thereby completing the present invention.
That is, the present invention is as follows.

[1]
An AS-based resin composition comprising an AS-based resin (a), a bio-based polyethylene (b), and a hydrogenated block copolymer (c),
The hydrogenated block copolymer (c) has a polymer block S mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units,
50 mol % or more of the conjugated diene portion constituting the hydrogenated block copolymer (c) is hydrogenated,
a mass ratio of the AS-based resin (a) to the bio-based polyethylene (b) is (a)/(b)=99/1 to 50/50;
The mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) is
(b)/(c)=90/10 to 50/50;
AS-based resin composition.
[2]
The bio-based polyethylene (b) is
The copolymer (b1) is an ethylene homopolymer and/or a copolymer (b2) of ethylene and an α-olefin, the copolymer (b2) being mainly composed of ethylene, and the copolymer (b1) has a bio-based content of 80% or more and 100% or less as defined in ASTM D6866.
The AS-based resin composition according to [1] above.
[3]
The hydrogenated block copolymer (c)
The AS-based resin composition according to [1] or [2] above, which contains 4 to 70% by mass of vinyl aromatic monomer units and 30 to 96% by mass of conjugated diene monomer units.
[4]
An injection-molded article of the AS-based resin composition according to any one of [1] to [3] above.
[5]
A blow molded article of the AS-based resin composition according to any one of [1] to [3] above.
[6]
An extrusion molded article of the AS-based resin composition according to any one of [1] to [3] above.

According to the present invention, an AS-based resin composition consisting of an AS-based resin, a bio-based polyethylene, and a specific hydrogenated block copolymer can be obtained, which has a desired bio-based content derived from the bio-based polyethylene and does not impair the excellent mechanical properties inherent to the AS-based resin, and a molded article can be obtained.

Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail.
Note that the following embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content, and the present invention can be implemented in various modified forms within the scope of its gist.

[AS-based resin composition]
The AS-based resin composition of the present embodiment is
An AS-based resin composition comprising an AS-based resin (a), a bio-based polyethylene (b), and a hydrogenated block copolymer (c),
The hydrogenated block copolymer (c) has a polymer block mainly composed of vinyl aromatic monomer units and a polymer block mainly composed of conjugated diene monomer units,
50 mol % or more of the conjugated diene portion constituting the hydrogenated block copolymer (c) is hydrogenated,
The mass ratio of the AS-based resin (a) to the bio-based polyethylene (b) is
(a)/(b)=99/1 to 50/50;
The mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) is
(b)/(c)=90/10 to 50/50.
By configuring the AS-based resin composition of the present embodiment as described above, it is possible to obtain an AS-based resin composition with a good balance of mechanical properties, which has a certain degree of bio-based content while at the same time not significantly impairing the other properties of AS-based resins, namely, rigidity, surface hardness, and chemical resistance, although it is difficult to achieve the transparency that is one of the properties originally required of AS-based resins. In addition, depending on the combination, it is possible to significantly improve the impact strength of the AS-based resin.

In addition, in this specification, the proportion of a monomer unit in a polymer is described as "mainly composed of," which means that the content of a specific monomer unit is 60% by mass or more. It is preferably 80% by mass or more, and more preferably 90% by mass or more.

(Mass ratio of ABS resin (a) to bio-based polyethylene (b))
In the AS-based resin composition of this embodiment, the mass ratio of the AS-based resin (a) to the bio-based polyethylene (b) is (a)/(b) = 99/1 to 50/50, preferably (a)/(b) = 95/5 to 50/50, more preferably (a)/(b) = 90/10 to 50/50, even more preferably (a)/(b) = 75/25 to 50/50, and still more preferably (a)/(b) = 75/25 to 60/40.
By using the above-mentioned mass ratio of the AS-based resin (a) to the bio-based polyethylene (b), it is possible to achieve the best possible balance between the value of introducing a bio-based content into the AS-based resin and the inherent advantages of the AS-based resin, such as excellent mechanical properties and processability.
When the mass ratio of the bio-based polyethylene (b) is 1 or more, it is meaningful to implement the present invention in terms of introducing a bio-based content into the AS-based resin.
Furthermore, by controlling the mass ratio of the bio-based polyethylene (b) to 50 or less, the AS-based resin composition can have excellent mechanical properties and processability.
The AS-based resin composition of this embodiment is based on the idea that the main component is an AS-based resin, and that the desired bio-based content is achieved by combining the AS resin with bio-based polyethylene.

(Mass ratio of bio-based polyethylene (b) to hydrogenated block copolymer (c))
In the AS-based resin composition of the present embodiment, the mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) is (b)/(c)=90/10 to 50/50, preferably (b)/(c)=80/20 to 55/45, and more preferably (b)/(c)=75/25 to 60/40.
By setting the mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) within the above range, a desired bio-based content can be achieved, and excellent mechanical properties and processability can be obtained.
The mass ratio of the bio-based polyethylene (b) of 50 or more is meaningful in terms of imparting a desired bio-based degree to the AS-based resin composition of this embodiment.
Furthermore, by setting the mass ratio of the bio-based polyethylene (b) to 90 or less, desired compatibility is obtained, and the AS-based resin composition of this embodiment can achieve excellent mechanical properties and processability.

(AS-based resin (a))
The AS-based resin composition of the present embodiment contains an AS (acrylonitrile/styrene)-based resin (a), also called SAN (styrene/acrylonitrile).
The AS-based resin (a) encompasses all so-called AS-based resins that have been distributed on the market up to the present time, and any of them can be suitably used regardless of the manufacturer or brand.
The AS-based resin (a) may be a neat polymer that does not contain functional secondary materials such as colorants, lubricants, fillers, and flame retardants, or may be a so-called compound grade that contains functional secondary materials. Furthermore, functional AS-based resins that have been copolymerized with comonomers such as maleimide to improve heat resistance, and AS-based resins copolymerized with (meth)acrylic monomers are also included in the AS-based resin (a) and can be used favorably. In addition, alloy materials with polycarbonate resins and acrylic resins are also included in the AS-based resin (a). ABS resins are resins in which butadiene rubber or the like is graft-copolymerized with AS, but are generally distinguished from AS-based resins in terms of intended use and performance, and in this specification, "AS-based resins" do not include ABS resins, but include variations of A and S monomers, that is, AS resins copolymerized with a specific comonomer other than butadiene as described above, those using styrene-based monomers having functional groups, alloys of AS and other resins, and resins including combinations of both.
The AS-based resin (a) can be produced by a known method, and may be an AS-based resin produced by emulsion polymerization or a solution polymerization.

Commercially available AS-based resins include, for example, "Cevian N (registered trademark)" manufactured by Daicel, "Toyolac (registered trademark) AS" manufactured by Toray, "LiTac-A (registered trademark)" manufactured by Nippon A&L, "Kibisan (registered trademark)" manufactured by Chimei Industries, "Rulan (registered trademark)" manufactured by Ineos, and "SAN" manufactured by LG Chemical.

(Bio-based polyethylene (b))
The AS-based resin composition of the present embodiment contains the bio-based polyethylene (b).
Bio-based polyethylene (b) is polyethylene using monomers derived from plants.
The bio-based polyethylene (b) is preferably an ethylene homopolymer (b1) having a bio-based content of 80% or more and 100% or less as specified in ASTM D6866, and/or a copolymer of ethylene and an α-olefin (b2) mainly composed of ethylene.
The bio-based polyethylene (b) may be a single bio-based polyethylene or a combination of multiple bio-based polyethylenes having different bio-based percentages.

The bio-based polyethylene (b) preferably has a bio-based content as defined in ASTM D6866 of 80% or more, more preferably 85% or more and 100% or less, even more preferably 90% or more and 100% or less, and even more preferably 95% or more and 100% or less.
Generally, the technology for bio-based production of ethylene monomer has been established, while at present, it is more advantageous from an economic and industrial standpoint to use fossil-derived α-olefins, and bio-based polyethylene incorporating α-olefins generally has a bio-based content of less than 100%.
In consideration of the purpose of introducing a desired bio-based content into the AS-based resin composition of this embodiment, it is preferable that the bio-based content of the bio-based polyethylene (b) is a relatively high value.

A representative example of bio-based polyethylene (b) is "green polyethylene," manufactured and sold by Braskem in Brazil under the brand name "I'm Green." The bio-based content of each brand of Braskem's green polyethylene is specified in the catalog on its website.
As the bio-based polyethylene (b), any type of polyethylene can be suitably used, including high density polyethylene (HDPE) type, low density polyethylene (LDPE) type, linear low density polyethylene (LLDPE) type, and the like.

The bio-based polyethylene manufactured and sold by Braskem is available in a variety of grades for various applications, from those with a high MFR value for injection molding to those with a low MFR value for blow molding, spinning, films, and the like, and can be suitably used for the AS-based resin composition of this embodiment.
When a brand of bio-based polyethylene (b) with a low MFR value is used, the mechanical properties such as impact resistance of the resulting AS-based resin composition tend to be better. For AS-based resin compositions, it is recommended to select a brand with a low MFR value for blow molding rather than a brand with a high MFR value for injection molding. Specifically, the difference in properties can be verified by comparing examples of AS-based resin compositions using bio-based polyethylenes with different MFRs in the examples described later.

The preferred MFR value of the bio-based polyethylene (b) is 0.1 or more and 30 or less under conditions of 190°C and a load of 2.16 kgf, and the more preferred MFR value is 0.1 or more and 10 or less, and the even more preferred MFR value is 0.1 or more and 3 or less, and the even more preferred MFR value is 0.1 or more and 1 or less. By using a bio-based polyethylene (b) having an MFR value in this range, an AS-based resin composition with excellent mechanical properties can be obtained.

The density of the bio-based polyethylene (b) also reflects the tendency of the physical properties of the AS-based resin composition.
Specifically, if a low-density type bio-based polyethylene is selected, the rigidity (flexural modulus) of the resulting AS-based resin composition tends to decrease, imparting flexibility; however, due in part to the effect of adding the hydrogenated block copolymer (c), which will be described later, the impact strength will be equivalent to that of the original AS-based resin, or, depending on the combination, will surpass that of the AS-based resin.
On the other hand, if a high density type bio-based polyethylene is selected, the rigidity of the resulting AS-based resin composition is maintained at approximately the same level as that of the original AS-based resin.
Thus, it is preferable to select the density type of the bio-based polyethylene (b) in consideration of the final use and from the viewpoint of the important physical properties.
Generally, the density range of the bio-based polyethylene (b) is in the range of 0.91 to 0.97 (g/cm ³ ).

The AS resin composition of this embodiment may contain a combination of bio-based polyethylene (b) and petroleum-based polyethylene, provided that the combination does not deviate from the spirit of the present invention. The use of petroleum-based polyethylene in combination reduces the bio-based content of the AS resin composition, so it is preferable to adjust the amount of petroleum-based polyethylene in consideration of the balance between mechanical properties and economic efficiency.

(Hydrogenated Block Copolymer (c))
The hydrogenated block copolymer (c) is a block copolymer containing vinyl aromatic monomer units and conjugated diene monomer units, in which 50 mol % or more of the conjugated diene portion is hydrogenated.
The hydrogenated block copolymer (c) has a polymer block S mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units, and may have two or more of either polymer block or both of the polymer blocks.

From the viewpoint of the balance between the rigidity and the impact strength of a molded article of the AS-based resin composition of this embodiment, the hydrogenated block copolymer (c) preferably contains 4 to 70% by mass of vinyl aromatic monomer units and 30 to 96% by mass of conjugated diene monomer units.
From the viewpoint of strength of a molded article of the AS-based resin composition of this embodiment, the AS-based resin composition contains at least one polymer block S mainly composed of a vinyl aromatic monomer unit.

In the hydrogenated block copolymer (c), 50 mol % or more of the conjugated diene portion is hydrogenated.
Hydrogenation of the conjugated diene portion changes it to an olefin structure, and compatibility with the bio-based polyethylene (b) is expressed. By increasing the hydrogenation rate to 50 mol % or more, compatibility with the bio-based polyethylene (b) is improved, and when it is made into a resin composition with an AS-based resin, it tends to easily exhibit a compatibilizing effect.
The hydrogenation rate can be quantified by known analytical methods, such as infrared absorption spectroscopy and ¹ H-NMR.

The hydrogenated block copolymer (c) has a hydrogenation rate of preferably 60 mol % or more, more preferably 70 mol % or more, even more preferably 80 mol % or more, and even more preferably 90 mol % or more.
The upper limit of the hydrogenation rate is not particularly limited, but is preferably 100 mol % or less.
When the hydrogenation rate is 50 mol % or more, the compatibility with the bio-based polyethylene (b) becomes good, and an AS-based resin composition having preferable mechanical properties can be obtained.
The hydrogenation rate of the hydrogenated block copolymer (c) can be controlled within the above-mentioned range by adjusting the type and amount of the hydrogenation catalyst, the amount of hydrogen supplied in the hydrogenation step, and the hydrogenation step time.

The polymer block S mainly composed of vinyl aromatic monomer units constituting the hydrogenated block copolymer (c) is preferably a polymer block containing 90 mass % or more of vinyl aromatic monomer units, from the viewpoint of the strength of the AS-based resin composition of this embodiment.
The polymer block B mainly composed of conjugated diene monomer units constituting the hydrogenated block copolymer (c) may be a conjugated diene polymer block composed solely of conjugated diene monomer units, or may be a copolymer block of conjugated diene monomer units and vinyl aromatic monomer units. In the case of the copolymer block, various copolymer block structures such as a uniform random structure or a tapered structure (wherein the composition ratio of monomers changes along the chain) can be used.

The hydrogenated block copolymer (c) may be a combination of two or more kinds of block copolymers having different average molecular weights, or a combination of two or more kinds of block copolymers having different copolymerization ratios of vinyl aromatic monomer units and conjugated diene monomer units.
The hydrogenated block copolymer (c) may contain other polymerizable monomer units other than the vinyl aromatic monomer units and the conjugated diene monomer units, as necessary.

The vinyl aromatic monomer unit constituting the hydrogenated block copolymer (c) can be formed using a vinyl aromatic compound. The vinyl aromatic compound may be any compound having an aromatic ring and a vinyl group in the molecule. Examples of the vinyl aromatic compound include, but are not limited to, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, 1,3-dimethylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, vinylnaphthalene, vinylanthracene, and 1,1-diphenylethylene.
These vinyl aromatic compounds may be used alone or in combination of two or more. Among these, styrene is preferred from the industrial and economical viewpoints.

The conjugated diene monomer units constituting the hydrogenated block copolymer (c) can be formed using a conjugated diene compound. The conjugated diene compound may be a diolefin having a pair of conjugated double bonds. Examples of the conjugated diene compound include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene.
These conjugated diene compounds may be used alone or in combination of two or more.
Among these, from the industrial and economical viewpoints, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred.

The hydrogenated block copolymer (c) preferably has a mass ratio of vinyl aromatic monomer units to conjugated diene monomer units of vinyl aromatic monomer units/conjugated diene monomer units of 4/96 to 70/30, more preferably vinyl aromatic monomer units/conjugated diene monomer units of 10/90 to 70/30, and even more preferably 20/80 to 70/30.
When the ratio of each monomer unit is within the above range, the resulting AS-based resin composition has a better balance between rigidity and impact strength.

When the mass proportion of the vinyl aromatic monomer unit in the hydrogenated block copolymer (c) is in the range of 4 mass % or more and 50 mass % or less, the elastic modulus of the resulting AS-based resin composition is somewhat low, but the composition is characterized by exhibiting high impact strength, and tends to surpass the performance of the original AS-based resin, that is, the AS-based resin that does not contain the bio-based polyethylene (b) or the hydrogenated block copolymer (c).
On the other hand, when the mass proportion of the vinyl aromatic monomer units in the hydrogenated block copolymer (c) is in the range of 50 mass % or more and 70 mass % or less, there is a tendency that an AS-based resin composition having well-balanced physical properties can be obtained while minimizing the decrease in the elastic modulus of the original AS-based resin.
In this manner, similarly to the above-described bio-based polyethylene (b), it is preferable to select the mass proportion of the vinyl aromatic monomer units in the hydrogenated block copolymer (c) in consideration of the final use and from the viewpoint of important physical properties.

The contents of the vinyl aromatic monomer units and the conjugated diene monomer units in the hydrogenated block copolymer (c) can be determined by the method described in the Examples below.
The contents of these monomer units can be controlled by adjusting the amounts and ratios of the respective monomers added in the polymerization step of the hydrogenated block copolymer (c).

The hydrogenated block copolymer (c) is not particularly limited, but examples thereof include block copolymers having block structures represented by the following general formulas (1) to (5).
S-B... (1)
S-(B-S) _n ... (2)
B-(S-B) _n ... (3)
S-(B-S-B) _n ... (4)
(S-B) _n X ... (5)
Here, S represents a polymer block mainly composed of vinyl aromatic monomer units, and B represents a polymer block mainly composed of hydrogenated conjugated diene monomer units. Furthermore, n represents any integer from 1 to 6. In (2) to (5), n is independent of each other and may be the same number or different numbers. X represents a coupling agent residue.

The above general formulas (1) to (4) represent linear hydrogenated block copolymers, and (5) represents a branched (also called star-shaped) hydrogenated block copolymer with the B moiety as the bond center, and either can be suitably used.
When the AS-based resin composition of the present embodiment is used for durable consumer goods, it is preferable to select the hydrogenated block copolymer (c) having two or more polymer blocks S mainly composed of vinyl aromatic monomer units, from the viewpoint of various required mechanical properties.
In this specification, the "polymer block mainly composed of vinyl aromatic monomer units" may be referred to as "polymer block S".

<Peak Molecular Weight and Molecular Weight Distribution of Hydrogenated Block Copolymer (c)>
The hydrogenated block copolymer (c) preferably has at least one peak molecular weight in the molecular weight range of 20,000 to 250,000 in a molecular weight distribution curve measured by gel permeation chromatography (GPC), which further improves the mechanical properties of the AS-based resin composition of the present embodiment.
From the same viewpoint, the hydrogenated block copolymer (c) more preferably has a peak molecular weight in the range of 30,000 to 150,000, and further preferably has a peak molecular weight in the range of 35,000 to 100,000. The peak molecular weight of the hydrogenated block copolymer (c) can be measured by the method described in the Examples below.

<Molecular Weight Distribution (Mw/Mn) of Hydrogenated Block Copolymer (c)>
The molecular weight distribution (Mw/Mn) of the hydrogenated block copolymer (c) is not particularly limited. For example, a hydrogenated block copolymer (c) having a large molecular weight distribution (Mw/Mn) can be obtained by associating the polymerization active ends of some polymers with a coupling agent or the like described below, or by combining polymers having different molecular weights.

Furthermore, by adding an appropriate amount of a polymerization initiator during the polymerization to initiate polymerization from new polymerization active sites, a hydrogenated block copolymer (c) which is a mixture of polymers having different molecular weights can be obtained.
On the other hand, by adding an alcohol such as ethanol in a molar equivalent amount smaller than the number of moles of the polymerization initiator to the polymerization system during the polymerization to terminate the polymerization of a part of the polymer, it is also possible to obtain a hydrogenated block copolymer (c) which is a mixture of polymers having different molecular weights.

<Content and Molecular Weight of Polymer Block S of Hydrogenated Block Copolymer (c)>
The content of the polymer block S mainly composed of vinyl aromatic monomer units in the hydrogenated block copolymer (c) can be obtained by calculating the mass ratio of the polymer block S component (excluding vinyl aromatic hydrocarbon monomer polymer components having an average degree of polymerization of about 30 or less) obtained by a method of oxidatively decomposing the block copolymer with tertiary butyl hydroperoxide using osmium tetroxide as a catalyst (the method described in I.M. KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)). The polymer block S component obtained by the above method can be measured by gel permeation chromatography (GPC) to obtain the molecular weight (Mn and Mv) of the polymer block S. In this specification, this method is referred to as the "osmium tetroxide method".

The content of polymer block S in the hydrogenated block copolymer (c) can also be determined by a method using a nuclear magnetic resonance (NMR) spectrometer (the method described in Y. Tanaka, et al., RUBBER CHEMISTRY and TECHNOLOGY 54, 685 (1981)) using the block copolymer before and after hydrogenation as a sample. In this specification, this analytical method is referred to as the "NMR method."

In this case, there is a correlation shown by the following formula between the content (referred to as Os) of the polymer block S mainly composed of vinyl aromatic monomer units measured by the osmium tetroxide method using a block copolymer before hydrogenation and the content (referred to as Ns) of the polymer block S mainly composed of vinyl aromatic monomer units measured by the NMR method using a block copolymer after hydrogenation.

(Os) = -0.012(Ns) ² + 1.8(Ns) -13.0 ... (F)

Therefore, in the present embodiment, when the content of the polymer block S in the hydrogenated block copolymer (c) is determined by the NMR method, the value of (Os) determined by the above formula (F) is regarded as the content of the polymer block S mainly composed of vinyl aromatic monomer units as defined in the present embodiment.

<Modification of hydrogenated block copolymer (c)>
The hydrogenated block copolymer (c) may be a modified product having a polar group.
Generally, a "polar group" is an atomic group in which there is a bias in electric charge between covalently bonded atoms, and generally refers to an atomic group containing heteroatoms such as oxygen, nitrogen, sulfur, phosphorus, and halogens.

By modifying the hydrogenated block copolymer (c), a graft reaction occurs with the base polymer of the AS resin (a) or the bio-based polyethylene (b), which are the objects to be modified. This makes it possible to achieve the effect of reinforcing the interface between the components through the compatibilization of the AS resin (a) and the bio-based polyethylene (b).
Furthermore, when the AS-based resin composition of the present embodiment contains a filler as a compounding material, the graft reaction with the filler exhibits an effect of promoting the dispersion of the filler.
However, the compatibility between the AS resin (a) and the bio-based polyethylene (b) is better when an unmodified hydrogenated block copolymer is used than when a modified hydrogenated block copolymer is used. Therefore, in consideration of the properties of the AS resin (a) and other blended secondary materials to be used, there are cases where it is better to modify the hydrogenated block copolymer (c) and cases where it is better to leave it unmodified, and therefore it is preferable to select each case accordingly.

When the hydrogenated block copolymer (c) is modified, the amount of polar groups added is generally 0.01% by mass to 10% by mass, preferably 0.01% by mass to 8.0% by mass, more preferably 0.05% by mass to 6.0% by mass, and even more preferably 0.05% by mass to 4.0% by mass, based on 100% by mass of the hydrogenated block copolymer (c).

Examples of polar groups include, but are not limited to, hydroxyl groups, carboxyl groups, carbonyl groups, thiocarbonyl groups, acid halide groups, acid anhydride groups, carboxylic acid groups, thiocarboxylic acid groups, aldehyde groups, thioaldehyde groups, carboxylic acid ester groups, amide groups, sulfonic acid groups, sulfonate groups, phosphoric acid groups, phosphoric acid ester groups, amino groups, imino groups, nitrile groups, pyridyl groups, quinoline groups, epoxy groups, thioepoxy groups, sulfide groups, isocyanate groups, isothiocyanate groups, silicon halide groups, silanol groups, alkoxy silicon groups, tin halide groups, boronic acid groups, boron-containing groups, boronate bases, alkoxy tin groups, and phenyl tin groups, and may be atomic groups containing at least one of these functional groups.

In particular, an atomic group having at least one functional group selected from the group consisting of an acid anhydride group, a carboxylic acid group, a hydroxyl group, an epoxy group, an amino group, an amide group, a silanol group, and an alkoxysilane group is preferred, more preferably an atomic group having at least one functional group selected from the group consisting of an acid anhydride group, a carboxylic acid group, a hydroxyl group, an epoxy group, an amino group, and an amide group, and even more preferably an atomic group having at least one functional group selected from the group consisting of an acid anhydride group, a carboxylic acid group, and a hydroxyl group.
When an acid anhydride is bonded to a block copolymer in the polar group formation process, the acid anhydride may react with moisture in the air, etc., and some of the acid anhydride may be formed as a carboxylic acid group, but the amount of such a group is not particularly limited.

<Method for producing hydrogenated block copolymer (c)>
The hydrogenated block copolymer (c) can be produced by a known technique.
A representative example of the conventional technology is a method of block copolymerizing a conjugated diene compound and a vinyl aromatic compound in a hydrocarbon solvent using an anionic initiator such as an organolithium compound, etc. For example, the copolymer can be produced by the methods described in JP-B-36-19286, JP-B-43-17979, JP-B-48-2423, JP-B-49-36957, JP-B-57-49567, and JP-B-58-11446.

[Polymerization solvent]
The hydrogenated block copolymer (c) can be obtained by block copolymerizing a vinyl aromatic compound and a conjugated diene compound in a hydrocarbon solvent.
The hydrocarbon solvent used in the production of the hydrogenated block copolymer (c) may be any conventionally known hydrocarbon solvent, including, but not limited to, aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane, alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, and methylcycloheptane, and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene.
These hydrocarbon solvents may be used alone or in combination of two or more. Among these, when an organolithium initiator is used, n-hexane and cyclohexane are generally used, and among these, cyclohexane is most widely used industrially and is preferably used.

[Polymerization initiator]
The polymerization initiator is not particularly limited, but for example, a polymerization initiator that exhibits anionic polymerization activity for conjugated diene compounds and vinyl aromatic compounds can be suitably used. Examples of the polymerization initiator include alkali metal compounds such as aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds.

The alkali metal used in the alkali metal compound is not particularly limited, but examples thereof include lithium, sodium, and potassium.
Suitable alkali metal compounds include, but are not limited to, aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, which include compounds containing one lithium atom per molecule, as well as dilithium compounds, trilithium compounds, and tetralithium compounds containing multiple lithium atoms per molecule.

Examples of such alkali metal compounds include, but are not limited to, n-propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, hexamethylene dilithium, butadienyl dilithium, isoprenyl dilithium, a reaction product of diisopropenylbenzene and sec-butyl lithium, and a reaction product of divinylbenzene, sec-butyl lithium, and a small amount of 1,3-butadiene.

As the alkali metal compound, organic alkali metal compounds disclosed in foreign patents such as U.S. Pat. No. 5,708,092, British Patent No. 2,241,239, and U.S. Pat. No. 5,527,753 can also be used. These can be used alone or in combination of two or more. Of these, n-butyllithium is the most preferred.

[Polymerization process]
In the polymerization process of the hydrogenated block copolymer (c), the content of the vinyl aromatic monomer unit and the content of the conjugated diene monomer unit in the finally obtained hydrogenated block copolymer (c) can be controlled by adjusting the charging ratio of the vinyl aromatic compound and the conjugated diene compound, which are the polymerization raw materials.

As the polymerization process for hydrogenated block copolymer (c), for example, a process in which a polymerization initiator is added during polymerization, a process in which a small amount of a multifunctional monomer having two or more reactive active sites is added to cause a partial coupling reaction, or a process in which alcohol, water, etc. having less than the number of polymerization active sites is added during polymerization, and then monomer is again supplied to continue polymerization, etc. can be suitably adopted. By appropriately selecting such a process, a hydrogenated block copolymer (c) containing multiple types of components with different molecular weights can be produced.

Methods for producing a copolymer block consisting of vinyl aromatic monomer units and conjugated diene monomer units include a method in which a mixture of a vinyl aromatic compound and a conjugated diene compound is continuously supplied to a polymerization system and polymerized, and a method in which a polar compound or a randomizer is used to copolymerize a vinyl aromatic compound and a conjugated diene compound.

Furthermore, the polar compound or randomizer also has the effect of increasing the proportion of vinyl bonds in the conjugated diene when the conjugated diene compound is polymerized alone.
The vinyl bond content of the hydrogenated block copolymer (c) can be controlled by using a Lewis base, for example, a compound such as an ether or an amine, as a vinylating agent. The amount of the vinylating agent used can be adjusted depending on the desired vinyl bond content.

Vinylating agents include, but are not limited to, ether compounds, tertiary amine compounds, etc.

Examples of the ether-based compound include, but are not limited to, ethers such as tetrahydrofuran, diethylene glycol dimethyl ether, and diethylene glycol dibutyl ether.
Furthermore, examples of the tertiary amine compounds include, but are not limited to, pyridine, N,N,N',N'-tetramethylethylenediamine, tributylamine, tetramethylpropanediamine, 1,2-dipiperidinoethane, bis[2-(N,N-dimethylamino)ethyl]ether, and the like.
These may be used alone or in combination of two or more.
As the tertiary amine compound, a compound having two amines is preferable, and among them, a compound having a structure showing symmetry in the molecule is more preferable, and N,N,N',N'-tetramethylethylenediamine, bis[2-(N,N-dimethylamino)ethyl]ether, and 1,2-dipiperidinoethane are further preferable.

The hydrogenated block copolymer (c) can be produced in the presence of an alkali metal alkoxide in order to control the amount of vinyl bonds. An alkali metal alkoxide is a compound represented by the general formula: MOR (where M is an alkali metal and R is an alkyl group), and it is possible to obtain a hydrogenated block copolymer (c) with a high amount of vinyl bonds.

The alkali metal of the alkali metal alkoxide is preferably sodium or potassium from the viewpoints of a high vinyl bond content, a narrow molecular weight distribution, a high polymerization rate, and a high block rate.
Examples of the alkali metal alkoxide include, but are not limited to, sodium alkoxides, lithium alkoxides, and potassium alkoxides having an alkyl group with 2 to 12 carbon atoms, preferably sodium alkoxides or potassium alkoxides having an alkyl group with 3 to 6 carbon atoms, and more preferably sodium t-butoxide, sodium t-pentoxide, potassium t-butoxide, and potassium t-pentoxide. Among these, sodium alkoxides such as sodium t-butoxide and sodium t-pentoxide are more preferable.

In the polymerization step of the hydrogenated block copolymer (c), when the polymerization is carried out in the coexistence of a vinylating agent, an organolithium compound, and an alkali metal alkoxide, it is preferable that the vinylating agent and the organolithium compound coexist in the following molar ratios (vinylating agent/organolithium compound), and the alkali metal alkoxide and the organolithium compound coexist in the following molar ratios (alkali metal alkoxide/organolithium compound).
Vinylation agent/organolithium compound molar ratio: 0.2 to 3.0
Alkali metal alkoxide/organolithium compound molar ratio: 0.01 to 0.3

The molar ratio of vinylating agent/organolithium compound is preferably 0.2 or more from the viewpoint of a high vinyl bond amount and a high polymerization rate, and is preferably 3.0 or less from the viewpoint of obtaining a narrow molecular weight distribution and high hydrogenation activity. The molar ratio of alkali metal alkoxide/organolithium compound is preferably 0.01 or more from the viewpoint of obtaining a high vinyl bond amount, a high polymerization rate, and a high block rate, and is preferably 0.3 or less from the viewpoint of obtaining a narrow molecular weight distribution and high hydrogenation activity. This improves the polymerization rate, and the vinyl bond amount of the target hydrogenated block copolymer (c) can be increased and the molecular weight distribution can be narrowed, and the block rate tends to be improved.
As a result, crystallization originating from the polyethylene structure of the hydrogenated conjugated diene block portion is inhibited, and the material exhibits flexible elastic properties, while at the same time being able to be made compatible with various polyolefin resins, including bio-based polyethylene (b).
By controlling the vinyl bond amount of the hydrogenated block copolymer (c), it becomes possible to satisfy various required properties according to the application, such as impact resistance, flexibility, etc., in addition to the function as a compatibilizer.

The optimum polymerization temperature in the polymerization step of the hydrogenated block copolymer (c) varies depending on the polymer structure. In the case of anionic polymerization using a polymerization initiator, the polymerization temperature is generally in the range of -10°C to 150°C, preferably 10°C to 100°C.
The time required for the polymerization is usually within 48 hours, preferably in the range of 0.1 to 10 hours.
The atmosphere of the polymerization system is preferably replaced with an inert gas such as nitrogen gas.
The polymerization pressure is not particularly limited as long as it is within a pressure range sufficient for maintaining the monomer and polymerization solvent in a liquid phase within the above polymerization temperature range.
Furthermore, it is preferable to take care not to unintentionally mix impurities, such as water, oxygen, carbon dioxide gas, etc., which may inactivate the polymerization initiator and the living polymer, into the polymerization system.

When obtaining a hydrogenated block copolymer (c) containing a random copolymer block, it is preferable to employ a method in which a mixture of a vinyl aromatic compound and a conjugated diene compound is continuously supplied to a polymerization system and polymerized, and/or a polar compound or a randomizer is used to copolymerize the vinyl aromatic compound and the conjugated diene compound.

In the production of the hydrogenated block copolymer (c), when an organic alkali metal is used as a polymerization initiator, a coupling reaction in which two or more molecules are bonded together to terminate the polymerization reaction can be suitably utilized.
The coupling reaction can be carried out by adding a coupling agent, as exemplified below, to the polymerization system. By adjusting the amount of the coupling agent added, only a part of the polymers in the polymerization system can be coupled, and uncoupled polymers and coupled polymers can coexist, thereby producing a hydrogenated block copolymer (c) having two or more peaks in the molecular weight distribution.

The coupling agent that can be suitably used in the production of the hydrogenated block copolymer (c) is not particularly limited, and examples thereof include any coupling agents having two or more functionalities.
Specific examples of the silane compounds containing an amino group include tetraglycidyl meta-xylylene diamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyl-p-phenylenediamine, tetraglycidyl diaminodiphenylmethane, diglycidyl aniline, diglycidyl orthotoluidine, γ-glycidoxyethyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, γ-glycidoxybutyl trimethoxysilane, γ-glycidoxypropyl triethoxysilane, γ-glycidoxypropyl tripropoxysilane, and γ-glycidoxypropyl tributoxysilane.
Other coupling agents include, for example, 1-[3-(triethoxysilyl)-propyl]-4-methylpiperazine, 1-[3-(diethoxyethylsilyl)-propyl]-4-methylpiperazine, 1-[3-(trimethoxysilyl)-propyl]-3-methylimidazolidine, 1-[3-(diethoxyethylsilyl)-propyl]-3-ethylimidazolidine, 1-[3-(triethoxysilyl)-propyl]-3-methylhexahydropyrimidine, 1-[3-(dimethoxymethyl ... [0043] Examples of silane compounds containing a silyl group include silane compounds such as 1-(2-ethoxyethyl)-3-[3-(trimethoxysilyl)-propyl]-tetrahydropyrimidine, 3-[3-(tributoxysilyl)-propyl]-1-methyl-1,2,3,4-tetrahydropyrimidine, 3-[3-(dimethoxymethylsilyl)-propyl]-1-ethyl-1,2,3,4-tetrahydropyrimidine, 1-(2-ethoxyethyl)-3-[3-(trimethoxysilyl)-propyl]-imidazolidine, and (2-{3-[3-(trimethoxysilyl)-propyl]-tetrahydropyrimidin-1-yl}-ethyl)dimethylamine.

Other coupling agents include, for example, γ-glycidoxypropyl triphenoxysilane, γ-glycidoxypropyl methyl dimethoxysilane, γ-glycidoxypropyl ethyl dimethoxysilane, γ-glycidoxypropyl ethyl diethoxysilane, γ-glycidoxypropyl methyl diethoxysilane, γ-glycidoxypropyl methyl dipropoxysilane, γ-glycidoxypropyl methyl dibutoxysilane, γ-glycidoxypropyl methyl diphenoxysilane, γ-glycidoxypropyl dimethyl methoxysilane, γ-glycidoxypropyl diethyl ethoxysilane, γ-glycidoxypropyl dimethyl ethoxysilane, γ-glycidoxypropyl dimethyl phenoxysilane, γ-glycidoxypropyl diethyl methoxysilane, γ-glycidoxypropyl Examples of silane compounds containing a glycidoxy group include silane compounds such as bis(γ-glycidoxypropyl)dimethoxysilane, bis(γ-glycidoxypropyl)diethoxysilane, bis(γ-glycidoxypropyl)dipropoxysilane, bis(γ-glycidoxypropyl)dibutoxysilane, bis(γ-glycidoxypropyl)diphenoxysilane, bis(γ-glycidoxypropyl)methylmethoxysilane, bis(γ-glycidoxypropyl)methylethoxysilane, bis(γ-glycidoxypropyl)methylpropoxysilane, bis(γ-glycidoxypropyl)methylbutoxysilane, and bis(γ-glycidoxypropyl)methylphenoxysilane tris(γ-glycidoxypropyl)methoxysilane.

Other coupling agents include silane compounds containing methacryloxy groups, such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-methacryloxyethyltriethoxysilane, bis(γ-methacryloxypropyl)dimethoxysilane, and tris(γ-methacryloxypropyl)methoxysilane.

Other coupling agents include, for example, β-(3,4-epoxycyclohexyl)ethyl-trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-triethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-tripropoxysilane, β-(3,4-epoxycyclohexyl)ethyl-tributoxysilane, β-(3,4-epoxycyclohexyl)ethyl-triphenoxysilane, β-(3,4-epoxycyclohexyl)propyl-trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-ethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-ethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldipropoxysilane, Examples of silane compounds containing an epoxycyclohexyl group include silane compounds such as silane, β-(3,4-epoxycyclohexyl)ethyl-methyldibutoxysilane, β-(3,4-epoxycyclohexyl)ethyl-methyldiphenoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylmethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-diethylethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylethoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylpropoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylbutoxysilane, β-(3,4-epoxycyclohexyl)ethyl-dimethylphenoxysilane, β-(3,4-epoxycyclohexyl)ethyl-diethylmethoxysilane, and β-(3,4-epoxycyclohexyl)ethyl-methyldiisopropeneoxysilane.
Other coupling agents include, for example, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropylene urea, and N-methylpyrrolidone.

When the coupling agent is added to the living end of the hydrogenated block copolymer (c), the structure of the living end of the hydrogenated block copolymer (c) is not particularly limited. From the viewpoint of the mechanical strength of the AS-based resin composition of the present embodiment, the living end is preferably a living end of a polymer block mainly composed of vinyl aromatic monomer units.
The amount of the coupling agent used is preferably 0.1 to 10 equivalents, and more preferably 0.5 to 4 equivalents, per equivalent of the living end of the hydrogenated block copolymer (c).
The coupling agents may be used alone or in combination of two or more kinds.

[Hydrogenation process]
The hydrogenated block copolymer (c) is produced by subjecting a part or all of the double bonds in the conjugated diene monomer units of the block copolymer obtained in the polymerization step to a hydrogenation reaction.
The catalyst used in the hydrogenation reaction is not particularly limited, and examples thereof include supported heterogeneous catalysts in which a metal such as Ni, Pt, Pd, Ru, etc. is supported on a carrier such as carbon, silica, alumina, diatomaceous earth, etc.; so-called Ziegler type catalysts using an organic salt or acetylacetone salt of Ni, Co, Fe, Cr, etc. and a reducing agent such as organoaluminum, etc.; so-called organic complex catalysts such as organometallic compounds such as Ru, Rh, etc.; and homogeneous catalysts in which organolithium, organoaluminum, organomagnesium, etc. are used as reducing agents for a titanocene compound. Among these, from the viewpoints of economy, colorability of the polymer, or adhesive strength, homogeneous catalyst systems in which organolithium, organoaluminum, organomagnesium, etc. are used as reducing agents for a titanocene compound are preferred.

The hydrogenation method is not particularly limited, and examples thereof include the methods described in JP-B-42-8704 and JP-B-43-6636, and preferably the methods described in JP-B-63-4841 and JP-B-63-5401. Specifically, a hydrogenated block copolymer solution can be obtained by hydrogenating the copolymer in an inert solvent in the presence of a hydrogenation catalyst.
The hydrogenation reaction is not particularly limited, but is preferably carried out after the deactivation step of the active terminals of the polymer described above from the viewpoint of exhibiting high hydrogenation activity. The hydrogenation step can be carried out by any of a batch process, a continuous process, or a combination thereof.

In the hydrogenation step, some of the conjugated bonds of the vinyl aromatic monomer units may be hydrogenated.
The hydrogenation rate of conjugated bonds in all vinyl aromatic monomer units is preferably 30 mol % or less, more preferably 10 mol % or less, and further preferably 3 mol % or less.
Considering that the mechanical properties are expressed by forming a microphase separation structure, it is preferable that the vinyl aromatic monomer units are not hydrogenated and are close to 0 mol %.

[Denaturation process]
The hydrogenated block copolymer (c) may be subjected to a modification step to introduce a polar group.
As the modification method, a known method can be applied. A method in which a compound having a polar group is used as a polymerization initiator and/or a polymerization terminator in the polymerization step (called terminal modification) may be carried out, or a method in which an unsaturated compound having a polar group is added to the hydrogenated block copolymer after the polymerization step using a single-screw or twin-screw extruder with or without the use of a radical generator to modify the copolymer (called main chain modification).

Specific methods for introducing polar groups into hydrogenated block copolymer (c) include, for example, melt kneading using an extruder or reacting by dissolving, dispersing, and mixing using a solvent. This is called grafting reaction or main chain modification. In addition, in the process of polymerizing hydrogenated block copolymer (c), it is also possible to use a method of polymerization using a monomer having a functional group, or a method of modifying the polymer with a compound having a functional group instead of alcohols, which are commonly used for polymerization termination reactions, to terminate the polymerization. This is called terminal modification.

The "polar group" can be formed using a modifying agent.
Examples of the modifying agent include, but are not limited to, tetraglycidyl meta-xylylene diamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, δ-valerolactone, 4-methoxybenzophenone, γ-glycidoxyethyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl dimethylphenoxysilane, bis(γ-glycidoxypropyl)methylpropoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropylene urea, N-methylpyrrolidone, maleic acid, maleic anhydride, maleic anhydride imide, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, glycidyl methacrylate ester, and crotonic acid.

The amount of the denaturing agent added can be measured by a known analytical method.
As a general method, for example, in the case of maleic anhydride modification, a titration method using sodium methoxide can be exemplified.

(Other additives that can be added to the AS-based resin composition)
The AS-based resin composition of the present embodiment may contain any compounding agent or additive within a range that does not deviate from the spirit of the present invention and does not impair the effects of the present invention.
Examples of compounding agents and additives include those commonly used in compounding resins or rubber-like polymers, and include, but are not limited to, inorganic fillers such as calcium carbonate, magnesium carbonate, silica, zinc oxide, carbon black, etc.; higher alcohols such as stearyl alcohol; higher fatty acids such as palmitic acid, stearic acid, behenic acid, etc.; higher fatty acid metal salts such as zinc stearate, calcium stearate, magnesium stearate, magnesium behenate, hydrogenated magnesium ricinoleate, etc.; lubricants and release agents such as fatty acid amides such as erucic acid amide and ethylene bisstearylamide; organic polysiloxanes such as paraffin oil, process oil, dimethyl silicone, and methylphenyl silicone; softeners and plasticizers such as mineral oil; hindered phenol-based and phosphorus-based heat stabilizers and antioxidants; hindered amine-based light stabilizers; benzotriazole-based ultraviolet absorbers; halogen-based and phosphorus-based flame retardants; reinforcing agents such as organic fibers, glass fibers, carbon fibers, and metal whiskers; and colorants such as organic pigments, inorganic pigments, and organic dyes.

(Method for producing AS-based resin composition)
The method for producing the AS-based resin composition of this embodiment is not particularly limited, but may be, for example, a method in which the AS-based resin (a), the bio-based polyethylene (b), and the hydrogenated block copolymer (c) are dry-blended in the form of pellets at room temperature, then fed into a hopper of a twin-screw extruder, and the mixture is heated, melted, and kneaded in the twin-screw extruder. The heated and melted AS-based resin composition is extruded from a die in the form of strands, and is pelletized again through a cooling bath to obtain a pellet-shaped resin composition.
The heat-melt kneading is not particularly limited as long as it is a kneader for a thermoplastic resin that can be heated and melted. For example, a kneader such as a kneader, a Banbury mixer, a roll, a ribbon blender, a single-screw extruder, or a twin-screw extruder can be suitably used.
In addition to the strand cut method using a cooling bath, a hot cut method, an underwater cut method, etc. can also be preferably used depending on the purpose.

In the method for producing an AS-based resin composition of this embodiment, the mass ratio of the AS-based resin (a) to the bio-based polyethylene (b) is (a)/(b) = 99/1 to 50/50, and the mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) is (b)/(c) = 90/10 to 50/50.
By using the above mass ratio, it is possible to obtain an AS-based resin composition that has a certain degree of bio-based content while not compromising the mechanical properties of the original AS-based resin and, depending on the combination, can exhibit impact strength that surpasses that of the original AS-based resin, resulting in an AS-based resin composition with excellent balance of mechanical properties.

[Molded body]
Examples of the molded article of the AS-based resin composition of the present embodiment include various molded articles obtained by various known molding methods, such as injection molded articles, blow molded articles, extrusion molded articles, etc. There are various applications depending on the molding method, and the applications are wide-ranging, including, for example, home appliances, office equipment, cosmetic containers, food containers, building material parts, daily necessities, stationery, etc.

The present embodiment will be described in more detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way to the following examples and comparative examples.

[AS-based resin (a), bio-based polyethylene (b), petroleum-based polyethylene (b')]
AS-based resins (a)-1 to -3, bio-based polyethylenes (b)-1 to -3, and petroleum-based polyethylenes (b')-X and -Y were obtained and used as brands sold by various manufacturers.
Table 1 below shows the manufacturer, brand name, and representative physical properties of AS-based resin (a).
Table 2 below shows the manufacturers, brand names, and representative physical properties of the bio-based polyethylene (b) and the petroleum-based polyethylene (b').

[Hydrogenated Block Copolymer (c)]
Each of the hydrogenated block copolymers (c) used in the examples and comparative examples described later was produced as follows.

(Production of hydrogenation catalyst)
The hydrogenation catalyst was prepared as follows.
1 L of dried and purified cyclohexane was placed in a nitrogen-substituted reaction vessel, and 100 mmol of bis(cyclopentadienyl)titanium dichloride was added. With sufficient stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for approximately 3 days to obtain a hydrogenation catalyst.

(Production of hydrogenated block copolymer)
According to the following production examples, hydrogenated block copolymers (c)-1 to -12 were produced.

<Production Example 1>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 75° C. under a nitrogen gas atmosphere.
Next, 0.14 parts by mass of n-butyllithium and 0.33 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.
Next, a cyclohexane solution containing 70 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 50 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 75° C.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-1.

<Production Example 2>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 75° C. under a nitrogen gas atmosphere.
Next, 0.17 parts by mass of n-butyllithium and 0.31 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 34 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.
Next, a cyclohexane solution containing 32 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 30 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 75° C.
Next, a cyclohexane solution containing 34 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-2.

<Production Example 3>
A jacketed tank reactor was used, and a predetermined amount of cyclohexane was placed in it. The temperature inside the reactor was adjusted to 65° C. under a nitrogen gas atmosphere.
Next, 0.16 parts by mass of n-butyllithium and 0.20 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 10 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over a period of about 10 minutes. After the supply, the reaction was continued for 5 minutes.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 15% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 10 minutes.
Next, a cyclohexane solution containing 60 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 50 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 65° C.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 10 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-3.

<Production Example 4>
A jacketed tank reactor was used, and a predetermined amount of cyclohexane was placed in it. The temperature inside the reactor was adjusted to 65° C. under a nitrogen gas atmosphere.
Next, 0.16 parts by mass of n-butyllithium and 0.20 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 5 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 5 minutes. After the supply, the reaction was continued for 5 minutes.
Next, a cyclohexane solution containing 20 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 10 minutes.
Next, a cyclohexane solution containing 55 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 50 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 65° C.
Next, a cyclohexane solution containing 20 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 10 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-4.

<Production Example 5>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 60° C. under a nitrogen gas atmosphere.
Next, 0.05 part by mass of n-butyllithium and 0.05 part by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 10 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over a period of about 10 minutes. After the supply, the reaction was continued for 5 minutes.
Next, 0.004 parts by mass of sodium t-pentoxide was added, followed by the addition of 1.50 parts by mass of tetramethylmethylenediamine, and then a cyclohexane solution containing 85 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over a period of about 60 minutes. After the supply, the reaction was continued for 10 minutes.
Next, a cyclohexane solution containing 5 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over about 5 minutes. After the feeding, the reaction was continued for 10 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the hydrogenated block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-5.

<Production Example 6>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 50° C. under a nitrogen gas atmosphere.
Next, 0.14 parts by mass of n-butyllithium and 0.27 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over about 10 minutes. After the feeding, the reaction was continued for 5 minutes.
Next, a cyclohexane solution containing 85 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over a period of about 60 minutes. After the supply, the reaction was continued for 10 minutes.
Next, tetraethoxysilane as a coupling agent was fed to the reactor in an amount of 0.1 times by mol relative to n-butyllithium. After the feeding, the reaction was continued for 10 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount of 0.9 times by mole relative to the amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 90 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85° C. The hydrogenation rate was adjusted by adjusting the amount of hydrogen supplied to the reactor.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the hydrogenated block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-6.

<Production Example 7>
Using the hydrogenated block copolymer (c)-1 obtained in Production Example 1, 2 parts by mass of maleic anhydride and 0.15% by mass of 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane (product name: Perhexa 25B, manufactured by NOF Corporation) as a radical initiator were added relative to 100 parts by mass of the hydrogenated block copolymer, and main chain modification was carried out by graft reaction to the hydrogenated block copolymer at a cylinder temperature of 220° C. using a twin-screw extruder TEX30α (screw diameter 30 mm, unidirectional twin-screw, L/D=42) manufactured by The Japan Steel Works, Ltd. In this manner, hydrogenated block copolymer (c)-7 modified with maleic anhydride was obtained.

<Production Example 8>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 75° C. under a nitrogen gas atmosphere.
Next, 0.14 parts by mass of n-butyllithium and 0.33 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.
Next, a cyclohexane solution containing 70 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 50 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 75° C.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85° C. The hydrogenation rate was adjusted by adjusting the amount of hydrogen supplied to the reactor.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-8.

<Production Example 9>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 75° C. under a nitrogen gas atmosphere.
Next, 0.14 parts by mass of n-butyllithium and 0.33 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.
Next, a cyclohexane solution containing 70 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 50 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 75° C.
Next, a cyclohexane solution containing 15 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85° C. The hydrogenation rate was adjusted by adjusting the amount of hydrogen supplied to the reactor.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-9.

<Production Example 10>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 60° C. under a nitrogen gas atmosphere.
Next, 0.05 part by mass of n-butyllithium and 0.05 part by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 10 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over a period of about 10 minutes. After the supply, the reaction was continued for 5 minutes.
Next, 0.004 parts by mass of sodium t-pentoxide was added, followed by the addition of 1.50 parts by mass of tetramethylmethylenediamine, and then a cyclohexane solution containing 87 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over a period of about 60 minutes. After the supply, the reaction was continued for 10 minutes.
Next, a cyclohexane solution containing 3 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over about 5 minutes. After the feeding, the reaction was continued for 10 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the hydrogenated block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-10.

<Production Example 11>
A jacketed tank-type reactor was used, and a predetermined amount of cyclohexane was placed therein. The temperature inside the reactor was adjusted to 75° C. under a nitrogen gas atmosphere.
Next, 0.17 parts by mass of n-butyllithium and 0.31 parts by mass of tetramethylmethylenediamine were added.
Next, a cyclohexane solution containing 38 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.
Next, a cyclohexane solution containing 24 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 30 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 75° C.
Next, a cyclohexane solution containing 38 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 15 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 100 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85°C.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the block copolymer.
Thereafter, the solvent was removed to recover the hydrogenated block copolymer (c)-11.

<Production Example 12>
A jacketed tank reactor was used, and a predetermined amount of cyclohexane was placed in it. The temperature inside the reactor was adjusted to 65° C. under a nitrogen gas atmosphere.
Next, 0.17 parts by mass of n-butyllithium was added. No tetramethylmethylenediamine was added.
Next, a cyclohexane solution containing 20 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 10 minutes.
Next, a cyclohexane solution containing 60 parts by mass of 1,3-butadiene at a concentration of 20% by mass was supplied to the reactor over about 50 minutes. After the supply, the reaction was continued for 10 minutes while adjusting the temperature inside the reactor to 65° C.
Next, a cyclohexane solution containing 20 parts by mass of styrene at a concentration of 20% by mass was fed to the reactor over a period of about 10 minutes. After the feeding, the reaction was continued for 10 minutes.

Thereafter, in order to completely terminate the polymerization, ethanol was added to the reactor in an amount equal to the molar amount of n-butyllithium to terminate the polymerization reaction.
Next, the hydrogenation catalyst was added to the obtained polymer solution in an amount of 80 ppm in terms of titanium per 100 parts by mass of the polymer, and a hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and a temperature of 85° C. The hydrogenation rate was adjusted by adjusting the amount of hydrogen supplied to the reactor.
After completion of the hydrogenation reaction, 0.25 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as an antioxidant to 100 parts by mass of the hydrogenated block copolymer.
Thereafter, the solvent was removed to recover the (hydrogenated) block copolymer (c)-12.

(Physical Properties of Hydrogenated Block Copolymer)
<Contents of Vinyl Aromatic Monomer Units (Styrene Units) and Conjugated Diene Monomer Units (Butadiene Units) in Each of Hydrogenated Block Copolymers (c)-1 to 12>
For each of the hydrogenated block copolymers obtained in Production Examples 1 to 12, the copolymerization ratio of each monomer component, styrene and 1,3-butadiene, was confirmed to be the same as the charge ratio at the time of polymerization by the following analytical method. A Shimadzu ultraviolet-visible spectrophotometer was used as the analytical instrument.

About 30 mg (weighed accurately to the nearest 0.1 mg) of each of the hydrogenated block copolymers (c)-1 to -12 was dissolved in 100 mL of chloroform, and the polymer solution was filled into a quartz cell and set in a UV-visible spectrophotometer, which was scanned with UV wavelengths of 260 to 290 nm. The aromatic ring of styrene exhibits absorptivity in this wavelength range, and the styrene composition ratio (mass%) contained in each hydrogenated block copolymer (c) was determined using a calibration curve prepared with a known sample based on the absorption peak height value obtained by measurement. The peak wavelength derived from styrene appears at 269.2 nm.
As a result, it was confirmed that there was no difference between the styrene charge ratio during polymerization and the styrene composition ratio in the hydrogenated block copolymer.
The composition ratio (mass %) of the hydrogenated butadiene portion was obtained by subtracting the composition ratio (mass %) of styrene from 100.

<Content of Polymer Block S Mainly Containing Vinyl Aromatic Monomer Unit (Styrene Unit) in Each of Hydrogenated Block Copolymers (c)-1 to 12>
The polymer solution containing each of the hydrogenated block copolymers (c)-1 to 12 obtained in the above Production Examples before hydrogenation was withdrawn from the reactor, and the content (mass%) of the polymer block S consisting only of vinyl aromatic monomer units constituting each hydrogenated block copolymer was measured.
Here, the "polymer block S mainly composed of vinyl aromatic monomer units of a hydrogenated block copolymer" does not include the vinyl aromatic monomer units in the polymer block B mainly composed of conjugated diene monomer units contained in the hydrogenated block copolymer, but means only the polymer block S mainly composed of vinyl aromatic monomer units.

First, an osmic acid tetroxide solution was prepared.
A solution was prepared by dissolving and mixing 1 g of osmium tetroxide and 2 kg of "Perbutyl H" (chemical name tertiary butyl hydroperoxide, purity 69%), available from NOF Corporation, in 3 L of tertiary butyl alcohol.

Next, the block copolymer before hydrogenation was dried using a vacuum dryer, and then about 20 mg was accurately weighed.
The weighed block copolymer was placed in a 300 mL Erlenmeyer flask and dissolved in about 10 mL of chloroform, after which 20 mL of the osmic tetroxide solution was added and the mixture was heated in a water bath at about 90° C. for 30 minutes, thereby decomposing the conjugated diene portion in the block copolymer.
After the water bath, the Erlenmeyer flask was cooled with running water, and about 200 mL of methanol was gently poured into the decomposed polymer solution to precipitate components that were not dissolved in the solvent.

The precipitated solid component is polymer block S consisting only of vinyl aromatic monomer units, and vinyl aromatic monomer units such as styrene monomer copolymerized in polymer block B mainly consisting of conjugated diene monomer units, styrene monomer not forming blocks, and styrene with a low degree of polymerization remain dissolved in the methanol/tertiary butyl alcohol/chloroform mixed solution. The precipitate was suction filtered using a glass filter, washed with pure methanol, and vacuum dried to isolate only polymer block S from hydrogenated block copolymer (c).
The polymer block S thus obtained was isolated and accurately weighed to accurately measure the content of the polymer block S mainly composed of vinyl aromatic monomer units in each hydrogenated block copolymer.

<Weight Average Molecular Weight Mw, Number Average Molecular Weight Mn, Molecular Weight Distribution Mw/Mn, Peak Molecular Weight, and Number of Molecular Weight Peaks of Hydrogenated Block Copolymers (c)-1 to 12>
The weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw/Mn), peak molecular weight, and molecular weight peak number of each of the hydrogenated block copolymers (c)-1 to 12 were measured by a gel permeation chromatography (GPC) apparatus under the following measurement conditions.

[Measurement condition]
GPC device: Tosoh HLC-8420
Column: Four TSKgel Super HZM-N columns connected in series (Tosoh Corporation) Column temperature: 40°C
Flow rate: 0.6 mL/min Detector: Refractometer (RI)
Solvent: Tetrahydrofuran

The sample for GPC measurement was prepared by dissolving approximately 10 mg of the polymer to be measured for molecular weight in 20 mL of tetrahydrofuran and filtering to remove insoluble matter.

The measurement method is described below.
First, a calibration curve was prepared using nine standard polystyrene samples with known molecular weights, each having a different molecular weight. The highest molecular weight standard polystyrene had a weight average molecular weight (Mw) of 1,090,000, and the lowest molecular weight was 1,050. Next, measurement samples were prepared in the above manner using each hydrogenated block copolymer whose molecular weight was to be measured.

After confirming that the temperature inside the tank in which the column was stored had become constant, the solution sample was injected and the measurement was started. After the measurement was completed, the obtained molecular weight distribution curve was subjected to statistical processing to calculate the weight average molecular weight (Mw) and number average molecular weight (Mn). The molecular weight distribution (Mw/Mn) was determined by dividing the obtained weight average molecular weight (Mw) by the number average molecular weight (Mn). The peak molecular weight and the number of molecular weight peaks were determined from the above molecular weight distribution curve.

<Melt flow rate (MFR) of hydrogenated block copolymer (c)>
The measurement was carried out in accordance with the standard ISO 1133 at a temperature of 200° C. and a load of 5 kgf.

Table 3 shows the amounts of monomers added during the production of each of the hydrogenated block copolymers (c)-1 to 12 obtained in Production Examples 1 to 12, the contents (mass%) of vinyl aromatic monomer units and conjugated diene monomer units, the hydrogenation rates of the conjugated diene portions, the molecular weight information based on the results of GPC measurement, and the melt flow rates.

[Production of AS-based resin composition]
Using AS-based resins (a)-1 to -3 shown in Table 1, bio-based polyethylenes (b)-1 to -3 and petroleum-based polyethylenes (b')-X and -Y shown in Table 2, and hydrogenated block copolymers (c)-1 to -12 shown in Table 3, AS-based resin compositions were produced by the methods described below.

The production was carried out using the following equipment:
(1) Single-screw extruder: Tanabe Plastics Machinery Co., Ltd. Single-screw extruder VS40-28
Screw diameter 40 mm, L/D = 28, 2 Dulmage kneading sections (2) Twin-screw extruder Japan Steel Works, Ltd. Twin-screw extruder TEX-30αII
Screw diameter 30 mm, L/D = 36
The above single screw extruder and twin screw extruder have different kneading performance, with the single screw extruder being weak kneading and the twin screw extruder being strong kneading. AS-based resin compositions were produced and various physical properties were confirmed on the assumption that such differences existed, but it was found that there was almost no difference in physical properties. Therefore, in the following examples and comparative examples, (1) production was carried out using a single screw extruder.

Components (a), (b), and (c) were dry-blended at room temperature in the form of pellets in the composition ratios shown in the table below, and then melt-kneaded in a single-screw extruder. The cylinder temperature was set to 220° C. Pellets of the AS-based resin composition were obtained by a strand-cut method.
The resin composition containing the hydrogenated block copolymer (c) was able to pull strands without any problems, but the resin compositions containing only the AS-based resin (a) and polyethylene (b) without the hydrogenated block copolymer (c) all exhibited surging, regardless of whether the polyethylene resin was bio-based or petroleum-based, and were unable to pull strands stably, requiring constant supervision by a worker to provide assistance.

[Characteristics of AS-based resin composition]
The AS-based resin compositions of the respective Examples and Comparative Examples were evaluated for various properties as follows.

(Bio-based ratio)
The measurement was performed in accordance with ASTM D6866, which is a test standard for biobased content.

(Melt Flow Rate (MFR))
The measurement standard was ISO 1133, and the measurements were performed at a temperature of 200°C and a load of 5 kgf. At 220°C and 10 kgf, which are general conditions for AS-based resins, the fluidity becomes significantly high, especially when bio-based polyethylene is blended, making the measurement itself difficult, so the above temperature and load conditions were adopted.

(Mechanical properties)
<Preparation of various test pieces using an injection molding machine>
Test pieces were prepared using the following molding machines for the tensile test, bending test, Charpy impact strength test, load deflection test, and Vicat softening temperature test using an ISO test piece mold, and for the Rockwell hardness test using a flat plate mold of 50 mm x 90 mm x 2 mmt.
Injection molding machine: Nissei Plastic Industrial Co., Ltd. FNX110III Hybrid type Mold clamping pressure: 110 tons, cylinder temperature: 230°C, mold temperature: 40°C
After each test piece was injection molded, it was cured for 24 hours in a temperature-controlled room at a temperature of 23° C. and a humidity of 50%, and then various characteristics were evaluated.

<Evaluation standards and conditions for mechanical properties>
Details of the evaluation conditions for each characteristic are as follows.
The values in the table are the average values for each n number.
Tensile test: Using a Minebea tensile/compression tester TG-5kN, the test was carried out in accordance with ISO 527-1 at a tensile speed of 50 mm/min in a thermostatic chamber at 23° C. with an n number of 4.
Bending test: Using a Minebea tensile/compression tester TG-5kN, the test was carried out in accordance with ISO178 at a compression speed of 2 mm/min in a thermostatic chamber at 23° C. with an n number of 4.
Charpy impact test: In accordance with ISO 179, both notched and unnotched tests were performed in a constant temperature room at 23° C., with an n value of 10 for each test piece. If the test piece did not break into two or more pieces after the test, it was marked as NB.
Rockwell hardness: Three 2 mm thick injection molded plates were stacked together, and the test was carried out in a constant temperature room at 23° C. in accordance with ISO 868, with an n number of 6.
Deflection test under load: Using a HDT device manufactured by Toyo Seiki Seisakusho, the test was carried out according to ISO 75-1, with the test piece flatwise and with an n number of 6.
Vicat softening temperature: Using a Toyo Seiki Seisakusho HDT device, according to ISO306, a test was performed on 6 test pieces cut into about 1/3 of the original size.

(Molding shrinkage rate of AS-based resin composition)
The molding shrinkage of the AS-based resin composition was evaluated by molding a test piece by injection molding.
The injection molding was performed using the same equipment as described above, and a mirror-finished flat mold with a thickness of 1 mm, short side of 100 mm, long side of 150 mm, and a film gate on the short side was used, and the cylinder temperature was 230°C, the mold temperature was 40°C, the injection speed and the measurement value were constant, and the injection pressure was increased by 1 MPa at the short shot point when the injection pressure was changed, and the molding cycle was 8 seconds for injection and 25 seconds for cooling, and 10 1 mm thick flat molded products were molded. Lines were drawn vertically and horizontally in a manner that connected the center points of the ejector pin marks located 10 mm inside each of the four corners of this 1 mm thick flat molded product, and the molding shrinkage rate of the 1 mm thick plate-shaped molded product was obtained by measuring the exact dimensions using a digital caliper.
The mold shrinkage in the machine direction was calculated by taking the average n10 value of the average values of the left and right dimensions (MD), and the mold shrinkage in the transverse direction was calculated by taking the average n10 value of the average values of the differences in shrinkage between the gate side and the opposite side (TD). The unit was expressed as %.

[Examples 1 to 18, Comparative Examples 1 to 18, Reference Example 1]
Various AS-based resin compositions were obtained by melt-kneading using the single-screw extruder under the extrusion conditions described above, using AS-based (a)-1 shown in Table 1, bio-based polyethylene (b)-1, petroleum-based polyethylene (b')-X and Y, and hydrogenated block copolymer (c) shown in Production Examples 1 to 12, or not used in some Comparative Examples.

Next, various test pieces were molded using the injection molding machine. Prior to injection molding, the samples were pre-dried at 90° C. for 2 hours.
The formulations and physical properties of the AS-based resin compositions are shown in Tables 4 to 6 below.

By blending a hydrogenated block copolymer (c) with a composition consisting of an AS-based resin (a) and a bio-based (or petroleum-based) polyethylene (b), a remarkable recovery in physical properties was observed in the tensile breaking elongation and Charpy impact strength (unnotched).
Although these Examples show a slight decrease in flexural modulus compared to the AS-based resin (a)-1 alone, some of them showed higher impact strength than the original AS-based resin alone depending on the selection of hydrogenated block copolymer (c).

In addition, the hydrogenated block copolymer (c)-5, which has a low styrene ratio close to the lower limit, is somewhat inferior in modifying effect to the hydrogenated block copolymers (c)-1, 2, 3, etc. in terms of tensile elongation at break and impact strength. However, a modifying effect was observed when compared with a system not containing the hydrogenated block copolymer (c).
On the other hand, it was revealed that the AS-based resin composition using the hydrogenated block copolymer (c)-2 having a high styrene ratio close to the upper limit has high flexural strength and flexural modulus and slightly low Charpy impact strength (notched), but has the characteristic of being able to exert a modifying effect while maintaining rigidity.

Compared to the AS-based resin (a)-1 alone shown in Reference Example 1, Comparative Examples 1, 3, 5, and 12, which did not contain the hydrogenated block copolymer (c) but contained bio-based (or petroleum-based) polyethylene (b), showed a significant decrease in physical properties in terms of tensile elongation at break and Charpy impact strength. It was clear that the incorporation of the resin resulted in an increase in cost with no other benefits and that the resin was not suitable for practical use.

The modifying effect of the hydrogenated block copolymer (c) was not limited to bio-based polyethylene, and was similar to that of petroleum-based polyethylene in terms of mechanical properties. However, considering that the rigidity is the same or slightly lower, and the notched Charpy impact strength is also the same or tends to be lower, compared to AS-based resin alone, there is no point in blending petroleum-based polyethylene. Although the introduction of bio-based polyethylene can reduce the composition ratio derived from fossil raw materials and has a modifying effect on physical properties, compositions with petroleum-based polyethylene are outside the scope of this invention.

[Examples 19 to 34, Comparative Examples 19 to 26, Reference Examples 2 to 3]
Various AS-based resin compositions were obtained by melt-kneading using a single-screw extruder under extrusion conditions using AS-based resins (a)-2 and (a)-3 shown in Table 1, bio-based polyethylenes (b)-1 and (b)-2, and hydrogenated block copolymers (c)-2 and (c)-3 shown in Production Examples 2 and 3, or using no copolymers in some Comparative Examples.

Next, various test pieces were molded using the injection molding machine. Prior to injection molding, the samples were pre-dried at 90° C. for 2 hours.
The formulations of the AS-based resin compositions and their physical properties are shown in Tables 7 and 8.

As is clear from these examples, regardless of the brand of AS-based resin (a), by blending hydrogenated block copolymer (c) with a resin composition consisting of AS-based resin (a) and bio-based polyethylene (b), a remarkable recovery in physical properties was observed in both tensile elongation at break and Charpy impact strength (unnotched) compared to AS-based resin (a) alone. Although these examples show a slight decrease in flexural modulus compared to AS-based resin (a) alone, some examples showed higher impact strength than the original AS-based resin alone, depending on the selection of hydrogenated block copolymer (c).

In particular, when focusing on the Charpy impact strength, it was found that the AS-based resin composition using the bio-based polyethylene (b)-1 had a higher overall strength than the AS-based resin composition using (b)-2. This is presumably because the AS-based resin (a) and the bio-based polyethylene (b) are inherently incompatible, and the high viscosity of the resulting particulate domain dispersion makes it easier for the hydrogenated block copolymer (c) to make them compatible.
Visual inspection of the fracture surfaces after the Charpy impact test showed that the AS-based resin composition using the bio-based polyethylene (b)-1 had whitened fracture surfaces and exhibited the ductile fracture characteristic of the AS-based resin (a). However, the AS-based resin composition using the bio-based polyethylene (b)-2 showed a lower degree of whitening on the fracture surface than the composition using (b)-1, and showed a tendency toward brittle fracture.

[Examples 35 to 38, Comparative Examples 27 to 30, Reference Example 1]
Furthermore, a series of physical properties were evaluated by varying the composition ratio of the bio-based polyethylene, using (a)-1 as the AS resin, (b)-3 as the bio-based polyethylene, and (c)-1 as the hydrogenated block copolymer.
The formulation of the AS-based resin composition and its physical properties are shown in Table 9 below.

[Molding shrinkage rates of Examples 2, 3, 9, 10, and Reference Example 1]
Next, the mold shrinkage of the AS-based resin composition was evaluated.
The AS-based resin compositions of Examples 2, 3, 9, and 10 described above were used and evaluated in comparison with the AS-based resin alone.
The evaluation results are shown in Table 10 below.

The AS-based resin composition containing the bio-based polyethylene of the present invention tends to have a slightly higher shrinkage rate than the AS-based resin alone, but it was found that by taking these shrinkage characteristics into consideration and optimizing the molding conditions and mold design, it is quite possible to design a practical product.

The AS-based resin composition of the present invention achieves carbon neutrality through the use of bayobase polyethylene, and can reduce carbon dioxide emissions from the manufacturing process to disposal. It has industrial applicability as a material for AS-based resin molded products, such as home appliances, automobiles, and daily necessities.

Claims (6)

An AS-based resin composition comprising an AS-based resin (a), a bio-based polyethylene (b), and a hydrogenated block copolymer (c),
The hydrogenated block copolymer (c) has a polymer block S mainly composed of vinyl aromatic monomer units and a polymer block B mainly composed of conjugated diene monomer units,
50 mol % or more of the conjugated diene portion constituting the hydrogenated block copolymer (c) is hydrogenated,
a mass ratio of the AS-based resin (a) to the bio-based polyethylene (b) is (a)/(b)=99/1 to 50/50;
The mass ratio of the bio-based polyethylene (b) to the hydrogenated block copolymer (c) is
(b)/(c)=90/10 to 50/50;
AS-based resin composition. The bio-based polyethylene (b) is
The copolymer (b1) is an ethylene homopolymer and/or a copolymer (b2) of ethylene and an α-olefin, the copolymer (b2) being mainly composed of ethylene, and the copolymer (b1) has a bio-based content of 80% or more and 100% or less as defined in ASTM D6866.
The AS-based resin composition according to claim 1 . The hydrogenated block copolymer (c)
Contains 4 to 70% by mass of vinyl aromatic monomer units and 30 to 96% by mass of conjugated diene monomer units;
The AS-based resin composition according to claim 1 . An injection molded article of the AS-based resin composition described in claim 1. A blow molded article of the AS-based resin composition according to claim 1. An extrusion molded product of the AS-based resin composition described in claim 1.