JP2023077335A - Styrene-based resin composition and injection blow-molded product using the same - Google Patents

Abstract

To provide a rubber-modified styrene-based resin composition suitable for injection blow molding, which reduces an environmental load by use of biomass raw materials, has excellent injection blow moldability, causes little mold staining during molding, and, when molded, has high impact strength of the neck region and buckling strength.SOLUTION: Provided is a styrene-based resin composition, comprising a styrene-based polymer (A-1); a biomass plasticizer (B) having a biomass carbon ratio (pMC%) of 10% or more; a higher fatty acid compound (C); and rubbery polymer particles (A-2) having an average particle diameter of 0.9-7.0 μm. Relative to the whole styrene-based resin composition (100 mass%), a content of the rubbery polymer particles (A-2) is 10-30 mass%, a content of the biomass plasticizer is 0.1-15 mass%, and a content of the higher fatty acid compound is 0.02-2.5 mass%.SELECTED DRAWING: None

Description

The present invention relates to a styrenic resin composition suitable for injection blow molding. More specifically, it is a styrenic resin composition that contains a biomass plasticizer with a biomass content of 10% or more for the purpose of reducing environmental load, and that can efficiently produce hollow containers with excellent strength by injection blow molding.

Styrene-based resins represented by rubber-modified styrene-based resins are used after being processed or molded into various forms according to a wide variety of applications such as miscellaneous goods, food packaging, and home appliances due to their moldability and mechanical strength. . In particular, when processing or molding a hollow container using a styrene resin, a deep container is easier to mold, and injection blow molding is widely used because of its high productivity. In addition, injection blow molding is suitable for manufacturing hollow containers in which the opening is heat-sealed, because only the opening of the hollow container can be made thick.
In addition, biomass raw materials are attracting attention from the viewpoint of reducing the environmental load, and the development of injection blow molding materials, which are composites of styrene resins and naturally derived raw materials, is underway. For example, Patent Document 1 discloses a styrenic resin composition containing a rubber-modified styrenic resin and polylactic acid and suitable for injection blow molding.

In recent years, in the technical field of injection blow molding, there has been a demand for the development of a molding material with excellent strength that can maintain a certain level of strength even when the thickness of the container is reduced. However, as the thickness is reduced, the mouth impact is lowered, and there arises a problem that cracks occur during air transport in a molding factory. Furthermore, the thinning of the wall reduces the buckling strength of the container, and when the container is filled with beverages and is transported, the problem arises that the container cannot withstand the load and deforms. Therefore, there is a demand for a molding material that has an excellent balance between mouth impact and buckling strength. Furthermore, from the viewpoint of improving the productivity of container molding, it is also required to reduce mold contamination.
For example, Patent Literature 2 discloses a technology for a molded beverage container that is excellent in both buckling strength and mouth strength.
Further, for example, Patent Document 3 discloses a rubber-modified styrene resin composition for highly branched injection blow molding, and mentions a technique for reducing the total amount of residual styrene monomer and residual polymerization solvent and reducing mold contamination. It is

International Publication No. 2021/132692 JP-A-10-76565 JP 2013-100435 A

In the technique of Patent Document 1, a polymer alloy of polylactic acid, which has a relatively high melting point and toughness among styrene-based resins and plant-derived biodegradable polymers, is being investigated. Since the compatibility of lactic acid is very low, there is a problem that it is difficult to design a product that satisfies mechanical properties such as impact resistance and elasticity required in the hollow container market. Moreover, since polylactic acid is incompatible with styrene-based resins, there is also the problem that it is difficult to recycle hollow container scraps.

The technique of Patent Document 2 above studies a molded beverage container that is excellent in both buckling strength and mouth strength. As a result, it can be considered that mold contamination at the time of molding worsens. In addition, the technology of Patent Document 3 is excellent for injection blow molding, and studies are being made on molding materials with a small total amount of residual styrene monomer and residual polymerization solvent. The effect of reducing is considered insufficient. Furthermore, Patent Documents 2 and 3 do not use biomass raw materials for the purpose of reducing the environmental load.
Therefore, in the techniques of Patent Documents 1 to 3, while using a biomass raw material, while maintaining a high level of mouth impact and buckling strength of the hollow container, the injection blow moldability is excellent, and the mold at the time of molding Technology for reducing fouling is not considered.
Therefore, the present invention reduces the environmental load by using biomass raw materials, has high mouth impact strength and buckling strength when injection blow molding is performed, and has less mold contamination during the injection blow molding. An object of the present invention is to provide a styrenic resin composition suitable for molding.

In view of the above problems, the inventor of the present invention has made intensive research and repeated experiments, and as a result, a rubber-modified styrene resin containing a styrene polymer (A-1) and rubber-like polymer particles (A-2) ( A), a biomass plasticizer (B) having a biomass carbon ratio (pMC%) of 10% or more, and a higher fatty acid compound (C) are mixed at a specific ratio to obtain the above-mentioned The inventors have found that the problem can be solved, and have completed the present invention.
The present invention provides a rubber-modified styrene resin (A) containing a styrene polymer (A-1) and rubber-like polymer particles (A-2), and biomass having a biomass carbon ratio (pMC%) of 10% or more. A styrenic resin composition containing a plasticizer (B) and a higher fatty acid compound (C), wherein 10 to 10 of the rubber-like polymer particles (A-2) are added to the styrenic resin composition as a whole. 30% by mass, 0.1 to 15.0% by mass of the biomass plasticizer (B), and 0.02 to 2.5% by mass of a higher fatty acid compound (C) as a release agent. It is a resin composition.

According to the present invention, a styrene-based polymer that reduces environmental load, has excellent injection blow moldability, exhibits high mouth impact strength and buckling strength when injection blow molded, and causes less mold contamination during the molding. It is possible to provide a resin composition and a hollow container molded article comprising the styrene-based resin composition.

Hereinafter, embodiments of the present invention (hereinafter referred to as "present embodiments") will be described in detail. can be implemented.

[Styrene resin composition]
The styrenic resin composition of the present embodiment comprises a styrenic polymer (A-1), rubber-like polymer particles (A-2) having an average particle size of 0.9 to 7.0 μm, and a biomass carbon ratio It contains a biomass plasticizer (B) having a (pMC ratio) of 10% or more and a higher fatty acid compound (C).
Then, the content of the rubber-like polymer particles (A-2) is 10 to 30% by mass, and the content of the biomass plasticizer (B) is 0.1 to 30% by mass with respect to the entire styrene resin composition. 15.0% by mass, and the content of the higher fatty acid compound (C) is 0.02 to 2.5% by mass.
As a result, it is possible to provide a styrene-based resin composition that has a reduced environmental load, has high mouth impact strength and buckling strength when molded into a container, is excellent in injection blow molding, and causes less mold contamination during molding.
Further, the styrene polymer (A-1) and the rubber-like polymer particles (A-2) are As the rubber-modified styrenic resin (A) to be contained, it can be blended with the styrenic resin composition of the present embodiment. The rubber-modified styrenic resin (A) blended in the styrenic resin composition of the present embodiment comprises the polymer matrix phase containing the styrenic polymer (A-1) and the polymer matrix phase dispersed in the polymer matrix phase. It preferably contains rubber-like polymer particles (A-2). Furthermore, the rubber-modified styrenic resin (A) containing 10 to 30% by mass of the rubber-like polymer particles (A-2) with respect to the rubber-modified styrenic resin (A) is the total styrenic resin composition ( 100% by mass), it is preferably contained in an amount of 82.5 to 99.88% by mass. In addition, the higher fatty acid compound (C) may be contained as a releasing agent.
In other words, the styrene resin composition of the present embodiment contains 82.5 to 99.88% by mass of rubber-modified styrene resin (A) and biomass plasticizing with respect to the entire styrene resin composition (100% by mass). It is preferable to contain 0.1 to 15.0% by mass of the agent (B) and 0.02 to 2.5% by mass of the higher fatty acid compound (C). As a result, it is possible to provide a styrene-based resin composition that reduces the environmental load, has high mouth impact strength and buckling strength when molded into a container, is excellent in injection blow molding, and causes less mold contamination during molding.

<Rubber-modified styrene resin (A) (hereinafter also referred to as component (A))>
The rubber-modified styrenic resin (A) of the present embodiment essentially contains a styrenic polymer (A-1) and rubber-like polymer particles (A-2).
In the present embodiment, the rubber-modified styrenic resin (A) means rubber-like polymer particles (rubber-like polymer particles (A-2 ).) can be dispersed. Also, the rubber-modified styrenic resin (A) can be produced by polymerizing a styrenic monomer in the presence of a rubber-like polymer.
Therefore, the styrene resin composition in the present embodiment may contain the styrene polymer (A-1) and the rubber-like polymer particles (A-2) separately, or the styrene polymer ( A-1) and the rubber-like polymer particles (A-2) may be contained as the rubber-modified styrenic resin (A). In this embodiment, the content of the rubber-modified styrenic resin (A) can be 82.5 to 99.88% by mass with respect to the entire styrenic resin composition (100% by mass). In addition, the content of the rubber-modified styrenic resin (A) is preferably 83 to 99% by mass, more preferably 84 to 98% by mass, even more preferably 85 to 97% by mass, and even more preferably 86 to 96% by mass. can be
Hereinafter, an embodiment using a rubber-modified styrene resin (A) will be described as an example of the styrene resin composition in the present embodiment.

-Styrenic polymer (A-1) and polymer matrix phase-
In the present embodiment, the monomer constituting the styrene polymer (A-1) is a styrene monomer (a) or a vinyl monomer (b) copolymerizable with a styrene compound. is preferred.
Among the monomers constituting the styrene polymer (A-1), the content of the styrene monomer (a) is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, still more preferably 70 to 100% by mass, still more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass. Each content can be obtained from the integral ratio of the spectrum measured by a proton nuclear magnetic resonance ( ¹ H-NMR) spectrometer.
Examples of the styrenic monomer (a) include styrene, α-methylstyrene, α-methyl p-methylstyrene, о-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, and ethylstyrene. , isobutylstyrene, and t-butylstyrene or styrene derivatives such as bromostyrene and indene. Styrene is particularly preferred. These styrenic monomers can be used singly or in combination of two or more.

In the present embodiment, the vinyl-based monomer (b) is not particularly limited, but examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Cyclohexyl (meth)acrylate and the like can be mentioned. These unsaturated carboxylic acid ester monomers can be used singly or in combination of two or more.

In the present embodiment, polystyrene is a homopolymer obtained by polymerizing a styrene-based monomer (a), and commonly available materials can be appropriately selected and used. Styrenic monomers (a) constituting polystyrene include, in addition to styrene, α-methylstyrene, α-methyl-p-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyl Styrene derivatives such as toluene, ethylstyrene, isobutylstyrene, and t-butylstyrene or bromostyrene and indene. Styrene is particularly preferred from an industrial point of view. These styrenic monomers (a) can be used singly or in combination of two or more. Polystyrene does not exclude further containing monomer units other than the above styrene-based monomer (a) units as long as the effects of the present invention are not impaired, but typically the styrene-based monomer (a ) units.

In the present embodiment, the weight average molecular weight (Mw) of the styrenic polymer (A-1) is preferably 100,000 to 300,000, more preferably 120,000 to 260,000, still more preferably 140. ,000 to 240,000, more preferably 150,000 to 230,000. When the weight-average molecular weight (Mw) is from 100,000 to 300,000, a resin having excellent balance between mechanical strength and fluidity can be obtained, and gel matter is less mixed. The weight average molecular weight (Mw) is a value obtained by standard polystyrene conversion using gel permeation chromatography.

In the present embodiment, the styrene polymer (A-1) or the styrene resin composition of the present embodiment contains vinyl cyanide monomers such as acrylonitrile monomer units and methacrylonitrile monomer units. It is preferable not to contain substantially. Specifically, the vinyl cyanide monomer preferably contains 10% by mass or less, preferably 5% by mass or less, relative to the total amount of the styrene polymer (A-1) or the polymer matrix phase. More preferably, it is contained in an amount of 2% by mass or less.
The content of the styrenic polymer (A-1) of the present embodiment is preferably 65 to 99.88% by mass, more preferably 85 to 99.8% by mass, relative to the entire styrenic resin composition (100% by mass). 88% by mass, 87 to 99.5% by mass, more preferably 88 to 98% by mass, even more preferably 89 to 97% by mass, and even more preferably 90 to 96.5% by mass.

-Rubber-like polymer-
The styrenic resin composition of the present embodiment essentially contains rubber-like polymer particles (=rubber-like polymer particles (A-2)). As described above, the rubber-like polymer particles (A-2) may be contained in the styrenic resin composition as part of the rubber-modified styrenic resin (A), or may be added to the styrenic polymer (A-1). On the other hand, rubber-like polymer particles (A-2) different from the rubber-like polymer particles (A-2) contained in the rubber-modified styrenic resin (A) are further blended and contained in the styrenic resin composition. may be
The rubber-modified styrenic resin (A) or the rubber-like polymer particles (A-2) contained in the styrenic resin composition of the present embodiment are, for example, encapsulating the styrenic polymer (A-1) inside. and/or the styrenic polymer (A-1) may be grafted on the outside. Further, the rubber-like polymer particles (A-2) of the present embodiment are composed of a styrene-based polymer (A-1) as a core and a rubber-like polymer as a shell that encloses the core. In addition to the core-shell structure, a styrene polymer (A-1) as a plurality of cores and a rubber-like polymer as a shell that includes the styrene polymer (A-1) as the plurality of cores comprising a salami structure.
In the present embodiment, the content of the rubber-like polymer particles (A-2) (rubber-like polymer (e.g., conjugated diene-based polymer such as polybutadiene) itself with respect to the entire styrenic resin composition (100% by mass) and the content of the styrenic polymer (A-1) included in the rubber-like polymer particles (A-2)) is preferably 10 to 30% by mass, more preferably It is 11 to 28% by mass, more preferably 12 to 27% by mass, further preferably 13 to 25% by mass.

Materials for the rubber-like polymer or rubber-like polymer particles (A-2) of the present embodiment include, for example, polybutadiene, polybutadiene encapsulating polystyrene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, Acrylonitrile-butadiene copolymers and the like can be used, but polybutadiene or styrene-butadiene copolymers are preferred. Both high cis polybutadiene with a high cis content and low cis polybutadiene with a low cis content can be used for the polybutadiene. Both a random structure and a block structure can be used as the structure of the styrene-butadiene copolymer. One or more of these rubber-like polymers can be used. Saturated rubber obtained by hydrogenating butadiene rubber can also be used.
Examples of such rubber-modified styrene resin (A) include HIPS (high impact polystyrene), ABS resin (acrylonitrile-butadiene-styrene copolymer), AES (acrylonitrile-ethylene propylene rubber-styrene copolymer), and the like. is mentioned.

In the present embodiment, the content of the rubber-like polymer contained in the rubber-modified styrenic resin (A) (the content of the rubber-like polymer (for example, a conjugated diene-based polymer such as polybutadiene) itself) The styrenic polymer (A-1) included in the coalesced particles (A-2) is not included.) is 2.5% with respect to the total amount (100% by mass) of the rubber-modified styrenic resin (A). 2 to 9.5% by mass is preferable, more preferably 2.4 to 9.0% by mass, more preferably 2.5 to 8.5% by mass, more preferably 2.6 to 8.0% by mass, more It is preferably 2.7 to 7.5% by mass, more preferably 2.8 to 7.0% by mass, still more preferably 3.1 to 6.5% by mass. If the content of the rubber-like polymer is less than 2.2% by mass, there is a concern that the mouth portion impact strength of the injection blow-molded container may decrease. Also, if the content of the rubber-like polymer exceeds 9.5% by mass, there is a concern that the buckling strength of the container may be lowered.
In the present disclosure, the content of the rubber-like polymer contained in the rubber-modified styrenic resin (A) is a value calculated using the method described in the Examples section.

In the present embodiment, the content of the rubber-like polymer particles (A-2) contained in the rubber-modified styrenic resin (A) (the content of the rubber-like polymer (for example, a conjugated diene polymer such as polybutadiene) itself and the content of the styrenic polymer (A-1) contained in the rubber-like polymer particles (A-2)) is the total amount of the rubber-modified styrenic resin (A) (100 mass% ), preferably 10 to 30% by mass, more preferably 11 to 28% by mass, still more preferably 12 to 26% by mass, still more preferably 13 to 25% by mass.
In the present disclosure, the content of the rubber-like polymer particles (A-2) contained in the rubber-modified styrenic resin (A) is a value calculated using the method described in the Examples section. .

In the present embodiment, the lower limit of the average particle size of the rubber-like polymer particles (A-2) contained in the rubber-modified styrenic resin (A) is 0 from the viewpoint of the balance between the mouth impact strength and the buckling strength. preferably 0.9 μm, more preferably 1.0 μm, more preferably 1.1 μm, more preferably 1.2 μm, more preferably 1.3 μm, more preferably 1.4 μm, even more preferably 1.5 μm is. The upper limit of the average particle size of the rubber-like polymer particles (A-2) is preferably 7.0 μm, more preferably 6.5 μm, more preferably 6.0 μm, more preferably 5.5 μm, and more preferably 5.5 μm. It is preferably 5.0 μm, still more preferably 4.5 μm. In the present disclosure, the average particle size of the rubber-like polymer particles (A-2) contained in the rubber-modified styrenic resin (A) is a value calculated using the method described in the Examples section.

In the present embodiment, the reduced viscosity of the styrenic polymer (A-1) contained in the rubber-modified styrenic resin (A) (this serves as an indicator of the molecular weight of the styrenic polymer (A-1).) is preferably in the range of 0.50 to 0.85 dL/g, more preferably in the range of 0.55 to 0.80 dL/g. If the reduced viscosity of the styrenic polymer (A-1) is less than 0.50 dL/g, the impact strength will decrease, and if the reduced viscosity exceeds 0.85 dL/g, the fluidity will decrease.
In the present disclosure, the reduced viscosity of the styrene polymer (A-1) is a value measured in a toluene solution at 30° C. and a concentration of 0.5 g/dL.

-Method for producing rubber-modified styrenic resin (A)-
In the present embodiment, the method for producing the rubber-modified styrenic resin (A) is not particularly limited. or solution polymerization), or bulk-suspension polymerization that shifts to suspension polymerization in the middle of the reaction, or emulsion graft polymerization that polymerizes a styrenic monomer in the presence of a latex of a rubber-like polymer. . In bulk polymerization, a mixed solution containing a rubber-like polymer, a styrenic monomer, and optionally an organic solvent, an organic peroxide, and/or a chain transfer agent is added to a complete mixing reactor or tank type. It can be produced by continuously supplying to a polymerization apparatus configured by connecting a reactor and a plurality of tank reactors in series.

In the present embodiment, the polymerization method of the styrenic polymer (A-1), which is the polymer matrix phase of the rubber-modified styrenic resin (A), is not particularly limited. A polymerization method can be suitably employed. The polymerization method mainly includes a polymerization step of polymerizing raw materials for polymerization (monomer components) and a devolatilization step of removing volatile matter such as unreacted monomers and polymerization solvent from the polymerization product.

An example of the method for polymerizing the styrene polymer (A-1) that can be used in the present embodiment will be described below.
When the raw materials for polymerization are polymerized to obtain the styrenic polymer (A-1), the raw material composition for polymerization typically contains a polymerization initiator and a chain transfer agent.
Polymerization initiators used for polymerization of the styrenic polymer (A-1) include organic peroxides such as 2,2-bis(t-butylperoxy)butane, 1,1-di(t-butylperoxy ) cyclohexane (perhexa C), peroxyketals such as n-butyl-4,4-bis(t-butylperoxy) valerate, di-t-butyl peroxide (perbutyl D), t-butyl cumyl peroxide, dicumyl peroxide Dialkyl peroxides such as acetyl peroxide, diacyl peroxides such as isobutyryl peroxide, peroxydicarbonates such as diisopropylperoxydicarbonate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as acetylacetone peroxide, t and hydroperoxides such as -butyl hydroperoxide. Among them, 1,1-di(t-butylperoxy)cyclohexane (Perhexa C) is preferable from the viewpoint of decomposition rate and polymerization rate. It is preferable to add 0.005 to 0.08% by mass based on the total amount of monomers.
Examples of the chain transfer agent used for polymerization of the styrene polymer (A-1) include α-methylstyrene linear dimer, n-dodecylmercaptan, t-dodecylmercaptan, 1-phenyl-2-fluorene, dipentene, chloroform and the like. Mercaptans, terpenes, halogen compounds, turpentines such as terpinolene, and the like can be mentioned. The amount of the chain transfer agent to be used is not particularly limited, but it is generally preferable to add about 0.005 to 0.3% by weight based on the monomer.

As a method for polymerizing the styrene-based polymer (A-1), solution polymerization using a polymerization solvent can be employed, if necessary. Examples of the polymerization solvent to be used include aromatic hydrocarbons such as ethylbenzene and dialkyl ketones such as methyl ethyl ketone, each of which may be used alone or in combination of two or more. Other polymerization solvents such as aliphatic hydrocarbons can be further mixed with the aromatic hydrocarbons as long as they do not reduce the solubility of the polymerization product. These polymerization solvents are preferably used in an amount not exceeding 25 parts by mass with respect to 100 parts by mass of the total monomers. If the amount of the polymerization solvent exceeds 25 parts by mass with respect to 100 parts by mass of the total monomers, the polymerization rate tends to decrease significantly and the mechanical strength of the resulting resin tends to decrease significantly. Addition of 5 to 20 parts by mass per 100 parts by mass of all monomers prior to polymerization facilitates homogenization of quality and is also preferable from the viewpoint of polymerization temperature control.

In the present embodiment, the apparatus used in the polymerization step for obtaining the styrenic polymer (A-1) is not particularly limited, and may be appropriately selected according to the polymerization method of the styrenic resin. For example, when bulk polymerization is employed, a polymerization apparatus in which one or a plurality of complete mixing reactors are connected can be used. Also, the devolatilization step is not particularly limited. For example, when adopting bulk polymerization, the unreacted monomer is preferably 50% by mass or less, more preferably 40% by mass or less. Then, devolatilization treatment is performed by a known method. More specifically, for example, a flash drum, a twin-screw devolatilizer, a thin-film evaporator, an extruder, or other ordinary devolatilizer can be used, but a devolatilizer with a small stagnant portion is preferred. The temperature of the devolatilization treatment is usually about 190 to 280.degree. C., more preferably 190 to 260.degree. The pressure of the devolatilization treatment is usually about 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, more preferably 0.13 to 2.0 kPa. Desirable devolatilization methods include, for example, a method of reducing the pressure under heating to remove the volatile matter, and a method of removing the volatile matter through an extruder or the like designed for the purpose of removing the volatile matter.

<Biomass plasticizer (B) (hereinafter also referred to as component (B))>
The styrenic resin composition in this embodiment contains a biomass plasticizer (B). The biomass plasticizer (B) has a biomass carbon ratio (pMC%) of 10% or more. If the biomass carbon ratio (pMC %) is within the above range, the amount of fossil fuel used can be reduced, so a styrenic resin composition that can reduce the environmental load can be provided.
In the present embodiment, the lower limit of the biomass carbon ratio (pMC%) is preferably 10% or higher, more preferably 25% or higher, even more preferably 50% or higher, and even more preferably 75% or higher.
In this embodiment, the content of the biomass plasticizer (B) is 0.1 to 15.0% by mass with respect to the total amount (100% by mass) of the styrene-based resin composition. The lower limit of the content of the biomass plasticizer (B) is preferably 0.5% by mass or more, more preferably 1.0% by mass or more. The upper limit of the content of the biomass plasticizer (B) is preferably 12.0% by mass or less, more preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and even more preferably 6.0% by mass. % by mass or less.
If the content of the biomass plasticizer (B) is too high, the fluidity of the resin increases, causing stringiness during injection blow molding, which may impair the appearance of the molded product. In addition, clogging of the slit is caused, and blow failure tends to occur frequently. On the other hand, if the content of the biomass plasticizer (B) is too small, the mouth impact strength will decrease. In addition, there is concern about a decline in productivity due to reduced liquidity.
It is preferable that the biomass plasticizer (B) is uniformly dispersed in the styrenic resin composition. More specifically, it is preferably not an external lubricant (eg, a lubricant insoluble in the polymer melt) that forms, for example, a monolayer of the biomass plasticizer (B) on the surface of the styrenic resin composition. Methods for uniformly dispersing the biomass plasticizer (B) in the styrene resin composition include, for example, a method of kneading the rubber-modified styrene resin (A) and the biomass plasticizer (B) with an extruder, and A method of including a biomass plasticizer (B) in the polymerization raw material composition when polymerizing is mentioned.

The biomass carbon ratio (pMC%) in the present specification indicates the carbon concentration (mass ratio) of biomass-derived components, and more specifically, by a radioactive carbon ( ¹⁴ C) measurement method in accordance with ASTM-D6866. ¹⁴ C content values obtained. The radiocarbon ( ¹⁴ C) measurement method utilizes the fact that fossil fuels do not contain ¹⁴ C, and biomass (or organism)-derived carbon absorbs ¹⁴ C in the atmosphere during the growth period. This is a method of estimating the biomass carbon ratio (pMC%) from the ¹⁴ C ratio in the carbon contained in materials (or organisms).
Therefore, by measuring the ratio of ^C14 contained in the total carbon atoms in the plasticizer of the present embodiment, the ratio of biomass-derived carbon can be calculated. In the present invention, the biomass carbon ratio (pMC%) is calculated by the following formula (1) using the method described in the Examples section below.
Formula (1):
Biomass carbon ratio (pMC%) = ( ¹⁴ C plasticizer/ ¹² C plasticizer)/( ¹⁴ C standard substance/ ¹² C standard substance) x 100
Also, oxalic acid (SRM4990) was used as a standard substance, and ( ¹⁴ C plasticizer/ ¹² C plasticizer)/( ¹⁴ C standard substance/ ¹² C standard substance) was calculated by the AMS method.

The weight average molecular weight (Mw) of the biomass plasticizer (B) of the present embodiment is preferably 200-7500, more preferably 300-5000, still more preferably 400-3000. When the weight average molecular weight (Mw) of the biomass plasticizer is 200 to 7500, a styrenic resin composition having an excellent balance between mechanical strength and fluidity can be obtained, and gel matter is less mixed. The weight average molecular weight (Mw) is a value obtained by standard polystyrene conversion using gel permeation chromatography, as described in the section of Examples below.

The biomass plasticizer (B) in the present embodiment refers to a plasticizer that uses biomass materials as part or all of the raw material, and refers to a plasticizer with a biomass carbon ratio (pMC%) of 10% or more. The biomass plasticizer (B) of the present embodiment is a plasticizer that uses a plant-derived biomass material as at least a part of the raw material and has a biomass carbon ratio (pMC%) of 10% or more. or polyester plasticizer, natural vegetable oil, modified vegetable oil, mixture of natural vegetable oil and mineral oil, mixture of modified vegetable oil and mineral oil, mixture of natural vegetable oil, modified vegetable oil and mineral oil, or polyester More preferably, it is a system plasticizer.
The vegetable oil used herein is a general term for plant-derived fats and oils, and includes natural vegetable oils and modified vegetable oils.

In this embodiment, modified vegetable oil may be used as the biomass plasticizer (B). Modified vegetable oil refers to a compound made from vegetable oil, more specifically, a part of a hydrocarbon-based oil derived from a plant is modified with a functional group, and the vegetable oil is modified with an epoxy group, an amino group, or an ester bond. It is preferable that The vegetable oils include triesters of glycerin and fatty acids, fatty acid monoesters obtained by adding monoalcohol to vegetable oil and transesterification, fatty acid monoesters obtained by esterification reaction of fatty acids and monoalcohols, and fatty acid monoesters. Contains derived ethers.
The modifying group (epoxy group, amino group, or ester bond functional group) of the modified vegetable oil in the present embodiment is substantially It is preferred that the polymer not be directly polymerized. Further, in the present embodiment, the modified vegetable oil preferably has a modification rate of 1 mmol% to 50 mmol% per 1 g of the modified vegetable oil.
The modification rate of the modified vegetable oil is calculated by the ¹ H-NMR measurement method as described in Examples below.

Specific examples of the natural vegetable oils include cottonseed oil, paulownia oil, shea oil, alfalfa oil, poppy oil, pumpkin oil, winter squash oil, millet oil, barley oil, quinoa oil, rye oil, kukui oil, passionflower oil, Avatar, aloe vera oil, sweet almond oil, peach kernel oil, soybean oil, cashew oil, peanut oil, avocado oil, baobab oil, borage oil, broccoli oil, calendula oil, camellia oil, canola oil, carrot oil, safflower oil, flax oil, rapeseed oil, cottonseed oil, coconut oil, pumpkin seed oil, wheat germ oil, jojoba oil, lily oil, macadamia oil, corn oil, medform oil, monoi oil, hazelnut oil, apricot kernel oil, walnut oil, olive oil, evening primrose oil, palm oil, blackcurrant seed oil, kiwi seed oil, grape seed oil, pistachio oil, musk rose oil, sesame oil, soybean oil, sunflower oil, castor oil, watermelon oil or mixtures of these oils.
Modified vegetable oils in the present embodiment include oils obtained by hydrogenating the natural vegetable oils exemplified above (e.g., hydrogenated castor oil); oils obtained by epoxidizing the natural vegetable oils exemplified above (e.g., modified epoxidized oils); Examples include oils obtained by aminated vegetable oils (eg, modified aminated oils). Such modified epoxidized oils include oils with ring-opened epoxy functional groups, such as hydroxylated modified soybean oil, oils that have been directly hydroxylated in advance, and cashew oil-based polyols.

Specific examples of the biomass plasticizer (B) of the present embodiment include, for example, palm oil, epoxidized soybean oil, epoxidized linseed oil, hardened castor oil, polyoxyethylenated castor oil, polyoxyethylenated hardened castor oil, Oleic acid ester or lauric acid ester, DIC Corporation "Polycizer W-1810-BIO", "Eposizer"; NOF Corporation "Newsizer 510R", "Newsizer 512"; Takemoto oils and fats "Pionin D series" manufactured by Co., Ltd.; .

In the present embodiment, the viscosity of the vegetable oil (including natural vegetable oil and modified vegetable oil) is preferably 1000 mPa·s or less at 25° C., and preferably 20 to 1000 mPa·s. more preferably 50 to 800 mPa.s. s is even more preferred.

The melting point of the biomass plasticizer (B) in the present embodiment is preferably −30 to 80° C., more preferably −25 to 77° C., still more preferably −22° C. to 74° C., still more preferably −18. ° C to 70 ° C, even more preferably -15 ° C to 67 ° C, even more preferably -10 ° C to 64 ° C, even more preferably -8 ° C to 61 ° C, even more preferably -5 ° C to 58 ° C, and More preferably -3°C to 55°C, particularly preferably -1°C to 52°C. When the melting point of the biomass plasticizer (B) is higher than 80°C, the biomass plasticizer (B) is difficult to melt in the styrene-based resin (A), making the addition or mixing operation difficult. On the other hand, if the melting point of the biomass plasticizer (B) is less than −30° C., it is necessary to use a compound containing many unsaturated bonds as the type of biomass plasticizer (B) that can be used. It is easy to degrade the physical properties. In general, all the double bonds in natural vegetable oils are cis-type, so it is thought that the more double bonds there are, the lower the intermolecular force and the lower the melting point.

In the present embodiment, the difference between the SP value of the styrenic polymer (A-1) and the SP value ((cal/cm ³ ) ^1/2 ) of the biomass plasticizer (B) is preferably less than ±2.5, more preferably less than 2.4, more preferably less than ±2.3, more preferably less than 2.2, more preferably less than 2.1, more preferably less than 2.0, more preferably less than 1.9, more preferably less than 1.8, more preferably less than 1.7, more preferably less than 1.6, more preferably less than 1.5, more preferably less than 1.4, more preferably less than 1.3, more preferably Less than 1.2, more preferably less than ±1.1, even more preferably less than ±1.0, even more preferably less than ±0.9, still more preferably less than ±0.8. When the difference between the SP value of the styrene polymer (A-1) and the SP value of the biomass plasticizer (B) is ±2.5 or more, the two are difficult to be compatible with each other.
The SP value of the styrenic polymer (A-1) in the present embodiment is preferably 7 to 11 ((cal/cm ³ ) ^1/2 ), more preferably 7.5 to 10.5. ((cal/cm ³ ) ^1/2 ), more preferably 7.8 to 10.2 ((cal/cm ³ ) ^1/2 ), still more preferably 8.0 to 10.0 ((cal/cm ³ ) ^1/2 ), still more preferably 8.0 to 9.8 ((cal/cm ³ ) ^1/2 ), still more preferably 8.0 to 9.6 ((cal/cm ³ ) ^{1 /2} ), still more preferably 8.0 to 9.4 ((cal/cm ³ ) ^1/2 ), still more preferably 8.0 to 9.2 ((cal/cm ³ ) ^1/2 ), Still more preferably 8.0 to 9.0 ((cal/cm ³ ) ^1/2 ).
Further, the lower limit of the SP value of the biomass plasticizer (B) in the present embodiment is more preferably 7.4 ((cal/cm ³ ) ^1/2 ) or more, more preferably 7.5 ((cal/ cm ³ ) ^1/2 ) or more, more preferably 7.6 ((cal/cm ³ ) ^1/2 ) or more, more preferably 7.7 ((cal/cm ³ ) ^1/2 ) or more, still more preferably It is 7.8 ((cal/cm ³ ) ^1/2 ) or more. The upper limit of the SP value is preferably 10.5 ((cal/cm ³ ) or less, more preferably 10.4 ((cal/cm ³ ) or less, more preferably 10.3 ((cal/cm ³ ) or less, more preferably 10.2 ((cal/cm ³ ) ^1/2 ) or less, more preferably 10.1 ((cal/cm ³ ) ^1/2 ) or less, more preferably 10.0 ((cal /cm ³ ) ^1/2 ) or less, more preferably 9.8 ((cal/cm ³ ) ^1/2 ) or less, more preferably 9.6 ((cal/cm ³ ) ^1/2 ) or less, more preferably is 9.4 ((cal/cm ³ ) ^1/2 ) or less, more preferably 9.2 ((cal/cm ³ ) or less, more preferably 9.0 ((cal/cm ³ ) or less, even more preferably is 8.8 ((cal/cm ³ ) ^1/2 ) or less.In addition, the preferred range of the SP value of the biomass plasticizer (B) in the present embodiment is the upper limit of the SP value and the SP value of It can be a range in which the lower limit is arbitrarily combined.
The solubility parameter (SP value) defined in this embodiment is calculated using the function of the cohesive energy density shown in the following formula.
SP value ((cal/cm ³ ) ^1/2 )=(ΔE/V) ^1/2 formula (1)
(ΔE indicates intermolecular cohesive energy (evaporation heat), V indicates the total volume of the mixed liquid, and ΔE/V indicates cohesive energy density.)
Also, the heat quantity change ΔHm due to mixing is expressed by the following formula using the SP value.
ΔHm=V( _δ1 - _δ2 )・Φ1・Φ2 Equation (2)
( _δ1 indicates the SP value of the solvent, _δ2 indicates the SP value of the solute, _Φ1 indicates the volume fraction of the solvent, and _Φ2 indicates the volume fraction of the solute.)
From the above formulas (1) and (2), the closer the values of _δ1 and _δ2 , the smaller the ΔHm and the smaller the Gimms free energy. get higher
As a method for obtaining the SP value in this specification, by comparing the solubility of the resin with various solvents with known SP values, the SP value of the unknown resin is calculated from the SP value of the solvent that is most compatible. Specifically, it was calculated using the turbidity titration method. In the present embodiment, a value calculated from the monomer composition is mainly used.
If the biomass plasticizer (B) of the present embodiment has a high boiling point, the amount of gas generated during molding is reduced, so from the viewpoint of working advantageously for reducing mold contamination, a relatively high boiling point (for example, injection blow) 260° C. or higher, which is the molding temperature). When the SP value of the biomass plasticizer (B) is within the above range, the intermolecular cohesive energy, that is, the heat of vaporization can be controlled within a predetermined range, so the boiling point tends to be high enough to reduce the amount of gas generated during molding. indicate.

In the present embodiment, the mineral oil includes, for example, atmospheric residual oil obtained by atmospheric distillation of crude oil such as paraffinic crude oil (including liquid paraffin), intermediate crude oil, and naphthenic crude oil; Distillate oil obtained by vacuum distillation of residual oil; the distillate oil is subjected to one or more refining processes such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, etc. and mineral oil obtained by isomerizing a wax (GTL wax) produced by the Fischer-Tropsch process or the like. These mineral oils may be used alone or in combination of two or more.
In this embodiment, when a mixture of vegetable oil and mineral oil is used as the biomass plasticizer (B), it is particularly limited if the biomass carbon ratio (pMC ratio) of the entire biomass plasticizer (B) is 10% or more. never.

<Higher fatty acid compound (C) (hereinafter also referred to as component (C))>
The styrenic resin composition of the present embodiment contains 0.02 to 2.5% by mass of the higher fatty acid compound (C) as an essential component with respect to the entire styrenic resin composition. The higher fatty acid compound (C) acts as a release agent and may be one or more selected from the group consisting of higher fatty acids and metal salts of higher fatty acids. The content of the higher fatty acid compound (C) is preferably 0.04 to 2% by mass, more preferably 0.06 to 1.7% by mass, and more preferably 0.08 to 0.08% by mass, based on the total styrene resin composition. 1.4% by weight, more preferably 0.1 to 1.0% by weight.
If the higher fatty acid compound (C) is less than 0.02% by mass, the releasability is poor, which unfavorably leads to a decrease in productivity. If the content of the higher fatty acid compound (C) exceeds 2.5% by mass, the releasability is not improved any further, and rather discoloration of the resin due to decomposition and deterioration of the higher fatty acid, burnt, scorching, and charring of the molded product. There is concern that problems such as deterioration of mold contamination may occur.
The higher fatty acid is a saturated linear carboxylic acid having 12 to 22 carbon atoms, and examples thereof include stearic acid, lauric acid, myristic acid, palmitic acid and behenic acid. The metal salt of a higher fatty acid is a metal salt of a saturated linear carboxylic acid having 12 to 22 carbon atoms. Examples of the metal include zinc, calcium, magnesium, aluminum, barium, lead, lithium, potassium, sodium and the like. When a higher fatty acid and a higher fatty acid salt are used together as the higher fatty acid compound (C), the total amount of the higher fatty acid and the higher fatty acid salt may be in the range of 0.02 to 2.5% by mass. Fatty acid salts can be used either singly or as a mixture of two or more.
It can also be used as a release agent in combination with polyethylene glycol, fatty acid alcohol, or silicon-based additives.

<Optional Addition Ingredients>
In addition to the above components (A) and (B), the styrenic resin composition of the present embodiment may optionally be added with known additives, processing aids, etc., as long as the effects of the present invention are not impaired. Ingredients can be added. These optional additives include flame retardants, dispersants, antioxidants, weathering agents, antistatic agents, fillers, antiblocking agents, coloring agents, anti-blooming agents, surface treatment agents, antibacterial agents, anti-staining agents ( Silicone oils described in JP-A-2009-120717, monoamide compounds of higher aliphatic carboxylic acids, and monoester compounds obtained by reacting higher aliphatic carboxylic acids with monohydric to trihydric alcohol compounds to prevent eye mucus agent) etc. may be added.
In this embodiment, the styrenic resin composition may contain a known flame retardant (phosphorus flame retardant, halogen flame retardant such as bromine flame retardant). However, from the viewpoint of fear of generating gas such as hydrogen bromide due to reaction with the biomass plasticizer (B) contained in the styrene resin composition, the content of the halogen flame retardant is It is preferably less than 3% by mass, more preferably less than 1% by mass, relative to the total amount (100% by mass) of.

The styrenic resin composition in the present embodiment preferably does not contain metal elements except for inevitable impurities, and more specifically, the content of metal elements is the total amount (100% by mass) of the styrenic resin composition. is preferably less than 3% by mass, more preferably less than 1% by mass, more preferably less than 0.5% by mass. If the styrene resin composition contains metal elements, particularly metal particles, not only will the mold used during molding be damaged, but metal powder from the mold will likely be mixed into the styrene resin composition.
The above metal elements are elements of groups 2 to 12 of the periodic table, group 1 other than hydrogen atoms, group 13 other than boron atoms, Ge, As, Sn, Pb, As, Sb, Bi, Se , Te, Po and At. These metal elements can be used singly or in the form of an alloy or mixture of two or more.
In this embodiment, a fatty acid ester compound, a polyethylene glycol compound, a terpene compound, a rosin compound, a fatty acid amide, a fatty acid compound, or a fatty acid metal salt can be used as the dispersant.
Examples of the antioxidant include phenol compounds, phosphorus compounds, thioether compounds, and the like.
The total content of the optional additive components may be 0.05 to 5% by mass with respect to the entire styrenic resin composition.

When using a modified vegetable oil as the biomass plasticizer (B) contained in the styrene resin composition of the present embodiment, the content of the hydroxyl group-containing compound with respect to the total amount (100% by mass) of the styrene resin composition It is preferably less than 3% by mass, more preferably less than 1% by mass. The hydroxyl group-containing compound of the present embodiment refers to a compound having a hydroxyl group in the polymer, such as (meth)acrylic acid, maleic acid, and phthalic acid. If the hydroxyl group-containing compound is 3% by mass or more, it reacts with the modified vegetable oil to cause gelation, which adversely affects the moldability or the appearance of the molded product. When natural vegetable oil is used as the biomass plasticizer contained in the styrenic resin composition, the amount of the hydroxyl group-containing compound is not specified.

The styrenic resin composition of the present embodiment may consist essentially of (A) component, (B) component, (C) component and optional additive components. Moreover, it may consist only of (A) component, (B) component, and (C) component, or only (A) component, (B) and (C) component, and an arbitrary additive component.
The phrase "consisting essentially of components (A), (B), (C) and optional components" is preferably 85 to 100% by mass, more preferably 85 to 100% by mass, based on the total amount of the styrenic resin composition. is 90 to 100% by mass, more preferably 95 to 100% by mass, even more preferably 98 to 100% by mass of (A) component and (B) component and (C) component, or (A) component, It means the (B) component, the (C) component and an optional additive component.
The styrenic resin composition of the present embodiment may contain unavoidable impurities in addition to components (A), (B), (C), and optionally added components within a range that does not impair the effects of the present invention. good.

[Physical properties of styrene resin composition]
<Melt mass flow rate (MFR)>
The melt mass flow rate (measured under conditions of 200° C. and 49 N load) of the styrenic resin composition of the present embodiment is 3.0 to 13.0, preferably 3.3 to 11.5, preferably 3.5. 5 to 10.0, more preferably 4.0 to 9.5. If the melt mass flow rate is lower than 3.0, the fluidity is poor and insufficient filling tends to occur during molding. Molding becomes possible by raising the molding temperature and the core temperature, but the release balance is lost, and the thickness tends to be uneven, making it difficult to obtain a good product. Further, if the melt mass flow rate exceeds 11.0, a defective phenomenon of stringing tends to occur between the injection mold and the parison, making continuous molding difficult.

<Vicat softening temperature>
The Vicat softening temperature of the styrenic resin composition of the present embodiment is preferably 75°C to 100°C, more preferably 78°C to 98°C, still more preferably 80°C to 96°C.

<Swelling Index of Rubber-Like Polymer Particles (A-2)>
The swelling index of the rubber-like polymer particles (A-2) of the present invention is preferably 7.0 to 14, more preferably 7.5 to 13.5, still more preferably 8, from the viewpoint of impact strength. 0-13. The swelling index is an index representing the degree of cross-linking of rubber particles. By setting the swelling index within the above range, the styrenic resin composition of the present invention has excellent impact properties. In the present disclosure, the swelling index of the styrenic resin composition is a value calculated using the method described in the Examples section.

[Injection blow molded product]
The method for producing an injection blow-molded article using the styrene-based resin composition of the present embodiment as a raw material is not particularly limited, and the article can be molded by a known method. Specifically, in injection blow molding, first, an intermediate body (for example, a bottomed parison) is molded from a styrene resin composition by injection molding, and then this intermediate body is softened into a core (a male mold for injection molding). ), and then pressurized air is sent from the core to swell up to the inner wall surface of the blow molding die, whereby a hollow molded article (eg, container) can be molded.
In the above molding method, the mold temperature is preferably 35 to 75°C, more preferably 40 to 60°C, and even more preferably 45 to 55°C in the step of blow molding the intermediate. . Also, the temperature of the styrene-based composition is preferably 210 to 260°C, more preferably 220 to 250°C. The ratio of the volume of the container to the volume of the intermediate (stretching ratio of the volume) is preferably 1.5 to 7 times, more preferably 2 to 5 times.

<Measurement and evaluation method>
The physical properties of the resin compositions and injection blow molded articles obtained in Examples and Comparative Examples were evaluated according to the following methods.

(1) Measurement of weight average molecular weight of styrene polymer (A-1) and biomass plasticizer (B) in rubber-modified styrene resin (A) used in Examples and Comparative Examples Styrene polymer (A- The weight average molecular weights of 1) and the biomass plasticizer (B) were measured under the following conditions and procedures.
- Sample preparation: 5 mg of a measurement sample was dissolved in 10 mL of tetrahydrofuran, and filtered through a 0.45 µm filter.
・Measurement conditions Equipment: TOSOH HLC-8220GPC
(Gel permeation chromatography)
Column: Two SHODEX GPC KF-606M connected in series Guard column: SHODEX GPC KF-G 4A
Temperature: 40°C
Carrier: THF 0.50 mL/min
Detector: RI, UV: 254 nm
Calibration curve: 11 types of TSK standard polystyrene manufactured by Tosoh Corporation (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4 , F-2, F-1, A-5000) were used. A calibration curve was created using a cubic linear approximation.

(2) Melt mass flow rate (MFR)
The melt mass flow rate (g/10 min) of the styrenic polymer (A-1) in the rubber-modified styrenic resin (A) used in Examples and Comparative Examples was measured according to ISO 1133 (at 200° C. , load 49 N).

(3) Measurement of Vicat softening temperature (°C) The Vicat softening temperature (°C) of the rubber-modified styrenic resin (A) and the styrenic resin composition used in the present examples and comparative examples was measured according to ISO 306, It was measured with a load of 49N.

(4) Content of rubber-like polymer particles (A-2) and measurement of swelling index Content of rubber-like polymer particles (A-2) in rubber-modified styrenic resin (A) or styrenic resin composition (mass %), and the swelling index was measured as follows. 1.00 g of the rubber-modified styrenic resin (A) or styrenic resin composition was accurately weighed into a sedimentation tube (this weight is defined as W1), 20 ml of toluene was added, and the mixture was shaken at 23°C for 1 hour, then centrifuged. (SS-2050A rotor: 6B-N6L manufactured by Sakuma Seisakusho Co., Ltd.) at a temperature of 4° C., a rotation speed of 20000 rpm, and a centrifugal acceleration of 45100×G for 60 minutes. The sedimentation tube was slowly tilted to about 45 degrees and the supernatant liquid was decanted and removed. Accurately weigh the mass of the toluene-containing insoluble matter (this mass is W2), then vacuum dry for 1 hour under conditions of 160 ° C. and 3 kPa or less, cool to room temperature in a desiccator, and then weigh the toluene insoluble matter. was accurately weighed (this mass is defined as W3).
The content and swelling index of the rubber-modified styrenic resin (A) or rubber-like polymer particles (A-2) in the styrenic resin composition, that is, the rubber-modified styrenic resin (A) or styrenic The content and swelling index of the rubber-like polymer particles (A-2) in the resin composition were determined.
Content of rubber-like polymer particles (A-2) = W3/W1 x 100
Swelling index of rubber-like polymer particles (A-2) = W2/W3

(5) Measurement of average particle diameter Measurements were made by the following methods.
Using a COULTER MULTISIZER III (trade name) manufactured by Beckman Coulter Co., Ltd. equipped with an aperture tube of 30 μm diameter, 0.05 g of the pellet-shaped rubber-modified styrene resin (A) or the pellet-shaped styrene resin composition was added to about dimethylformamide. It was placed in 5 ml and left for about 2-5 minutes. Next, the dimethylformamide-soluble portion was measured as an appropriate particle concentration, and the volume-based median diameter was determined.

(6) Measurement of Content of Rubber-Like Polymer 0.25 g of the rubber-modified styrenic resin (A) or styrenic resin composition used in Examples and Comparative Examples was dissolved in 50 mL of chloroform, and iodine monochloride was added. After the double bonds in the rubber component were reacted, potassium iodide was added to convert the remaining iodine monochloride into iodine, followed by back titration with sodium thiosulfate (iodine monochloride method). By this method, the mass of the rubber contained in the rubber-modified styrenic resin (A) or the styrenic resin composition (this mass is defined as W4) is measured, and this value and the rubber-modified styrenic resin (A) or styrene Based on the mass of the resin composition (this mass is defined as W1), the content (% by mass) of the rubber-like polymer in the rubber-modified styrene resin (A) or the styrene resin composition is obtained by the following formula. rice field.
Rubber-modified styrenic resin (A) or rubber-like polymer content (% by mass) in styrenic resin composition = W4/W1 x 100

(7) Quantification of biomass plasticizer (B) content In the quantification of the content of the biomass plasticizer (B) in the styrenic resin compositions used in Examples and Comparative Examples, the following (1) or (2) Either procedure was used. Comparing the value obtained from (1) with the value obtained from (2), equivalent values were obtained.
(7-1) Calculation using NMR Dissolve vegetable oil (glycerin fatty acid ester) in deuterated chloroform (containing 1% TMS) containing 2-dimethoxyethane as an internal standard substance, and perform ¹ H-NMR measurement. rice field. Taking the TMS peak as a reference of 0 ppm, the peak derived from protons bonded to the carbon adjacent to the ester group of vegetable oil at δ 4.0 to 4.4 ppm and the peak derived from 1,2-dimethoxymethane at 3.4 to 3.6 ppm. A peak is detected. When the peak area derived from 1,2-dimethoxymethane is set to 1, the peak area derived from vegetable oil is calculated. By performing this operation while changing the concentration of the vegetable oil, a calibration curve for the concentration of the vegetable oil was created.
The pellet-shaped styrenic resin composition obtained in Examples or Comparative Examples was dissolved in deuterated chloroform (containing 1% TMS), ¹ H-NMR measurement was performed, and styrene The vegetable oil content in the system resin composition was quantified.
In the above method, if other peaks overlap with the peaks of the internal standard substance and quantification is difficult, an appropriate substance may be used as the internal standard substance.
In addition, the vegetable oil can be quantified by the triglyceride-derived peak detected at 5.0 to 5.5 ppm.
(2) Calculation of methanol-soluble content 1.0 g of the pellet-shaped styrene resin composition obtained in Examples or Comparative Examples (this weight is W11) was placed in a 20 mL screw bottle, and 10 mL of methyl ethyl ketone was added. added. Then, after completely dissolving the pellet with a shaker, 5 mL of methanol was further added to precipitate the styrenic polymer (A-1) as an insoluble matter, centrifuged at 2000 G for 10 minutes using a centrifuge, Insoluble matter was spun down. Then, the precipitated insoluble matter was pre-dried for 40 minutes in a dryer heated to 140° C., and then vacuum-dried at the same temperature for 20 minutes to completely evaporate the solvent. The mass of the insoluble matter after drying was measured, and this mass was defined as W12. Using the measured masses W11 and W12, the methanol-soluble content (W13) was defined as follows.
Methanol soluble matter (W13) was taken as W11-W12.
In addition, in this operation, the supernatant liquid after centrifugal sedimentation with a centrifuge is measured by GC-MS, and the content of styrene-based oligomers, residual monomers, residual solvents, and other low-molecular-weight substances other than plasticizers soluble in methanol was quantified, and the mass (W14) contained in 1.0 g of the styrene resin composition was calculated. Using the calculated masses W13 and W14, the content of the biomass plasticizer (B) in the styrene-based resin composition was determined as follows.
Content of biomass plasticizer (B) = W13 - W14

(8) Calculation of Modification Rate For styrene resin containing modified vegetable oil, calculate the modification rate of the modified vegetable oil by ¹ H-NMR using either procedure (8-1) or (8-2) below. Is possible.
(8-1) The pellet-shaped styrenic resin composition obtained in Examples or Comparative Examples is dissolved in deuterated chloroform (containing 1% TMS) and subjected to ¹ H-NMR measurement. Using TMS as a reference of 0 ppm, a peak derived from an epoxy group at δ 2.8 to 3.2 ppm and a peak derived from a proton bonded to the carbon adjacent to the ester group of vegetable oil at δ 4.0 to 4.4 ppm are confirmed. Thus, the epoxy modification rate was calculated from the above two peak area ratios. A peak derived from an epoxy group at δ 2.8 to 3.2 ppm and a peak derived from a proton bonded to a carbon adjacent to an ester group of vegetable oil at δ 4.0 to 4.4 ppm are detected, but these peaks are other peaks. Quantitation becomes difficult if it overlaps, so in that case, quantify by method (2).
(8-2) 1 g of the pelletized styrene resin composition obtained in Examples or Comparative Examples was placed in a 20 mL screw bottle, and 10 mL of methyl ethyl ketone was added. After completely dissolving the pellets with a shaker, 5 mL of methanol was added to precipitate the styrenic resin composition as an insoluble matter in the solution. Next, the insoluble portion was removed, the solution portion was taken in an eggplant flask, and the flask was vacuumed for 2 hours using an evaporator to volatilize methyl ethyl ketone and methanol. Thereafter, the liquid (vegetable oil) remaining in the eggplant flask was added to deuterated chloroform (containing 1% TMS), and ¹ H-NMR measurement was performed. Using TMS as a reference of 0 ppm, a peak derived from an epoxy group at δ 2.8 to 3.2 ppm and a peak derived from a proton bonded to the carbon adjacent to the ester group of vegetable oil at δ 4.0 to 4.4 ppm are confirmed. Thus, the epoxy modification rate was calculated from the above two peak area ratios.

(9) Mouth impact strength The injection blow-molded container is laid down so that the parting line is up and down, and the container is placed so that a falling weight hits the mouth. A falling weight impact strength (DuPont impact strength) was measured using a testing machine (No. 451). The test was conducted with a falling weight mass of 200 g, an impact point radius of 9.4 mm, and n=30, and the falling weight impact strength was determined from the 50% breaking height. A weight of 3.0 kg·cm or more was regarded as acceptable.

(10) Mouth compression strength The injection blow molded container is laid down so that the parting line is up and down, compressed at a speed of 200 mm / min so that the mouth flange hits vertically, and the load until it deforms 10 mm was taken as mouth compressive strength. Two shots of the container were used for the measurement, and the measured values were averaged. A container opening compressive strength of 23 or more was regarded as acceptable. As a measuring device, a desktop precision universal testing machine (Autograph AGS-5kNX) manufactured by Shimadzu Corporation was used.

(11) Buckling strength When the injection blow molded container is fixed to the lower platen for compression test and a load is applied at a pressing speed of 200 mm/min by a compression load jig protruding from the movable part of the compression tester. Compressive strength was measured. As a measuring device, a desktop precision universal testing machine (Autograph AGS-5kNX) manufactured by Shimadzu Corporation was used. The measured results were evaluated according to the following criteria. If the buckling strength is less than 120 N, the rigidity is insufficient, and problems such as buckling of the container occur in practical use.

(12) Formability (number of stringing occurrences)
The method for evaluating the number of occurrences of stringing in the present examples and comparative examples was based on whether or not stringing could be visually confirmed at the bottom of the molded product when a rigid cylindrical container was molded with an injection blow molding machine. SG125NP manufactured by Sumitomo Heavy Industries, Ltd. was used as an injection blow molding machine. Molding was carried out at a cylinder and hot runner temperature of 240°C and a mold temperature of 50°C. 140 molded containers corresponding to 10 shots were checked, and evaluation was performed based on the number of samples for which stringiness was confirmed.

(13) Moldability (number of defective blows)
The method for evaluating the number of defective blows in the present examples and comparative examples was based on whether or not the parison formed by injection molding separated from the mold when molding a rigid cylindrical container with an injection blow molding machine. SG125NP manufactured by Sumitomo Heavy Industries, Ltd. was used as an injection blow molding machine. Molding was carried out at a cylinder and hot runner temperature of 240°C and a mold temperature of 50°C. When it was confirmed that the parison after molding stuck to the mold and could not be completely removed, it was counted as 1 piece, and evaluation was made by the number of mold release failures when molding was performed a total of 100 times. If the number of defective blows exceeds 10, the productivity decreases, so 10 or less was judged to be acceptable.

(14) Moldability (number of shots at which mold contamination occurs)
The method for evaluating the number of defective blows in the present examples and comparative examples was the number of shots until deposits on the mold were visually observed when a rigid cylindrical container was molded with an injection blow molding machine. SG125NP manufactured by Sumitomo Heavy Industries, Ltd. was used as an injection blow molding machine. Molding was carried out at a cylinder and hot runner temperature of 240°C and a mold temperature of 50°C. If deposits on the mold were found after less than 100 shots, maintenance of the mold would take a long time and productivity would decrease.

(15) Calculation of SP value The SP value of each material used in the examples and comparative examples is the solubility parameter using the Hildebrand method (including the Hansen method), and the literature value (“Basics of Biomaterials” “Kazuhiko Ishizuka・Takao Hanawa and Mizuo Maeda, edited by Nihon Igakukan Publishing) or "J. Appl. Polym. Sci., 12, 2359 (1968)".
In addition, in the styrenic resin compositions of Examples and Comparative Examples, the SP values can be easily calculated by the above-described method, since each component to be blended in the composition is known. On the other hand, when the details of the styrenic polymer or plasticizer contained in the unknown styrenic resin composition are unknown, the SP value can be calculated by the following procedures (i) to (iv). Procedure (i): A target sample (styrene polymer or plasticizer) recovered or separated from a styrene resin composition is added to a solvent with a known SP value, and the sample is added to a solvent with a known SP value. Perform a dissolution test to determine whether or not is dissolved. Procedure (ii): Next, the SP values of the solvents in which the dissolution test of procedure (i) was performed are three-dimensionally plotted. Procedure (iii): Procedures (i) and (ii) are performed with 15 to 20 solvents. Procedure (iv): By calculating a sphere containing the coordinates of the solvent in which the sample was dissolved and not containing the coordinates of the solvent in which the sample was not dissolved, the center coordinates of the sphere represent Hansen's SP value, and the distance from the origin is Solubility parameters using the Hildebrand method (including the Hansen method) are calculated by representing the distance as the Hildebrand SP value.
The SP values calculated by the above procedures (i) to (iv) generally agree with the above literature values or the SP values calculated by the turbidimetric titration method.

Materials used in Examples and Comparative Examples are as follows.
(butadiene rubber)
Polybutadiene rubber (diene 55 manufactured by Asahi Kasei Chemicals Co., Ltd.), polybutadiene rubber UBEPOL BR (BR15HB manufactured by UBE Elastomer Co., Ltd.)

[Biomass plasticizer (B)]
(denatured vegetable oil)
Epoxidized soybean oil (product name “Newsizer 510R” (manufactured by NOF Corporation), weight average molecular weight (Mw = 1500), biomass carbon ratio (pMC%) 100%, melting point: 5 ° C., SP value (by Hansen method Calculated value, the distance from the origin in three-component coordinates of the dispersion force term (δD), the polar term (δP), and the hydrogen bond term (δH)): 9.0 ((cal/cm ³ ) ^1/2 ), Epoxy modification rate: 5 mmol per 1 g
Epoxidized linseed oil (product name “O-180A” (ADEKA Co., Ltd.), weight average molecular weight (Mw = 1500), biomass carbon ratio (pMC%) 100%, melting point: -2 ° C., SP value (calculated by Hansen method and the distance from the origin in the three-component coordinates of the dispersion force term (δD), the polar term (δP) and the hydrogen bonding term (δH)): 9.3 ((cal/cm ³ ) ^1/2 )), Epoxy modification rate: 8 mmol per 1 g
(natural vegetable oil)
Palm oil (product name “Multi Ace 20 (S)” (Nisshin OilliO Group Inc.), weight average molecular weight (Mw = 1000), biomass carbon ratio (pMC%) 100%, melting point: 22 ° C., SP value (Hansen is a value calculated by the method, and the distance from the origin in the three-component coordinates of the dispersion force term (δD), the polar term (δP), and the hydrogen bond term (δH)): 8.2 ((cal/cm ³ ) ^1/2 ))
Soybean oil (product name “soybean white oil (S)” (Nissin OilliO Group Co., Ltd.) weight average molecular weight (Mw = 1000), biomass carbon ratio (pMC%) 100%, melting point -8 ° C., SP value (Hansen is a value calculated by the method, and the distance from the origin in the three-component coordinates of the dispersion force term (δD), the polar term (δP), and the hydrogen bond term (δH)): 8.2 ((cal/cm ³ ) ^1/2 ))
Castor hydrogenated oil (product name "castor hydrogenated oil" (Ito Seiyu Co., Ltd.), weight average molecular weight (Mw = 1000), biomass carbon ratio (pMC%) 100%, melting point 85 ° C., SP value (calculated by Hansen method and represents the distance from the origin in the three-component coordinates of the dispersion force term (δD), the polar term (δP), and the hydrogen bond term (δH).): 10.1 ((cal/cm ³ ) ^1/2 ))

[others]
(liquid paraffin)
Liquid paraffin, product name "PS350S" (manufactured by Sanko Chemical Industry Co., Ltd.), weight average molecular weight (Mw = 250), biomass carbon ratio (pMC%) 0%, pour point: -12.5 ° C., SP value (literature value ): 7.3 (cal/cm ³ ) ^1/2
(polylactic acid)
Polylactic acid, product name “LX175” (manufactured by Total Corbinion PLA), biomass carbon ratio (pMC%) 100%, melting point: 155°C, SP value (literature value): 10.3 (cal/cm ³ ) ^1/2

[Method for producing styrene resin composition]
[Example 1]
(Method for producing composition (PS-1))
Styrene 92.1% by mass, ethylbenzene 6.0% by mass, polybutadiene rubber (manufactured by Asahi Kasei Chemicals Corp. Diene 55) 3.2% by mass, Multiace 20 (S) (manufactured by Nisshin Oillio Group Co., Ltd.) 0.8% by mass was continuously charged into a 6.2-liter laminar flow reactor-1 equipped with a stirrer and capable of temperature control in three zones at 3.24 liters/hour, and the temperature was raised to 121°C/ Adjusted to 125°C/131°C. The number of revolutions of the stirrer was 70 revolutions per minute. The reaction rate at the reactor outlet was 26%.
Subsequently, the reaction solution was sent to a laminar flow reactor-2 of 6.2 liters, which was equipped with a stirrer connected in series with the laminar flow reactor-1 and capable of temperature control in three zones. The stirring speed of the stirrer was set to 40 revolutions per minute and the temperature was set to 136°C/140°C/144°C. Subsequently, the reaction solution was sent to a 6.2-liter laminar flow reactor-3 equipped with a stirrer and capable of temperature control in three zones. The rotation speed of the stirrer was 10 rpm and the temperature was set to 146°C/148°C/150°C.
The polymer solution continuously discharged from the polymerization reactor (laminar flow reactor-3) is heated to 230°C in an extruder equipped with a vacuum vent, under reduced pressure of 0.8 kPa, devolatilized and then pelletized into pellets. A composition (PS-1) was prepared.
Next, a 3:1 mixture of stearic acid/calcium stearate was blended as a release agent so as to be 0.25% by mass with respect to the entire styrenic resin composition, and kneaded in an extruder. A styrenic resin composition was produced. Moreover, the polymer matrix phase of the styrene-based resin composition contained polystyrene, and the SP value of the polystyrene was 8.6 (cal/cm ³ ) ^1/2 .

[Examples 2 to 36]
(Method for producing compositions (PS-2) to (PS-35) and (PS-44))
Compositions (PS-2) to (PS-35) were produced in the same manner as composition (PS-1) except that the polymerization conditions were changed as shown in Table 1-1. The styrenic resin composition (composition (PS-44)) of Example 36 had a palm oil content of 3% by mass with respect to the entire styrenic resin composition after manufacturing the composition (PS-36). and kneaded with the composition (PS-36) in an extruder so that the content of a 3:1 mixture of stearic acid/calcium stearate as a release agent was 0.25% by mass. .

[Comparative Examples 1 to 9]
<Method for producing compositions (PS-36) to (PS-43) and (PS-45)>
Compositions (PS-36) to (PS-43) were produced in the same manner as composition (PS-1) except that the polymerization conditions were changed as shown in Table 1-2.
The styrene resin composition (composition (PS-45)) of Comparative Example 7 was the composition (PS-36 ), a 3:1 mixture of stearic acid/calcium stearate was added as a release agent, and kneaded in a twin-screw extruder.

The present invention provides a styrenic resin composition that is excellent in reducing environmental load, is excellent in injection blow moldability, and is excellent in mechanical strength of molded articles when injection blow molding is performed, and an injection blow made of the styrenic resin composition. It is to provide a molded article. Molded articles obtained from the styrenic resin composition can be suitably used for beverage containers and the like.

Claims (6)

A rubber-modified styrenic resin (A) containing a styrenic polymer (A-1) and rubber-like polymer particles (A-2) having an average particle size of 0.9 to 7.0 μm, and a biomass carbon ratio (pMC %) is 10% or more of a biomass plasticizer (B) and a higher fatty acid compound (C), comprising:
With respect to the entire styrene resin composition (100% by mass),
The content of the rubber-like polymer particles (A-2) is 10 to 30% by mass, the content of the biomass plasticizer (B) is 0.1 to 15% by mass, and the higher fatty acid compound is contained. A styrenic resin composition in an amount of 0.02 to 2.5% by mass. The styrenic resin composition according to claim 1, wherein the biomass plasticizer (B) has an SP value of 7.4 to 10.5. 3. The styrenic resin composition according to claim 1, wherein the styrenic polymer (A-1) has an SP value of 7.0 to 11.0. The styrenic resin composition according to any one of claims 1 to 3, wherein the styrenic polymer (A-1) has a weight average molecular weight of 140,000 to 240,000. The styrenic polymer (A-1) contains 65 to 99.88% by mass with respect to the entire styrenic resin composition (100% by mass), and the total amount of the styrenic polymer (A-1) The styrenic resin composition according to any one of claims 1 to 4, wherein the content of styrenic monomer units is 50% by mass or more. An injection blow molded article obtained by injection blow molding the styrene resin composition according to any one of claims 1 to 5.