JP2024037611A - Styrenic resin composition and molded article thereof - Google Patents

Abstract

To provide a styrenic resin composition that employs biomass material to reduce environmental load, exhibits superior mechanical strength, and can be molded at low temperatures, and a molded article thereof.SOLUTION: A styrenic resin composition comprises 30-84.9 mass% of a styrenic resin (A) comprising a styrenic monomer unit, and more than 15 mass% and 70 mass% or less of a biomass plasticizer (B) with a biomass carbon ratio (pMC%) of 10% or more.SELECTED DRAWING: None

Description

The present invention relates to a styrenic resin composition and a molded article made of the styrenic resin.

Styrene resins are used for a variety of purposes such as miscellaneous goods and home appliances due to their moldability and mechanical strength. Furthermore, biomass materials are attracting attention from the perspective of realizing a low-carbon society and a recycling-oriented society, and composite materials of styrene-based resin materials and naturally-derived biomass materials are being considered.
For example, Patent Document 1 discloses a styrenic resin composition containing rubber-modified polystyrene, polylactic acid, and a thermoplastic elastomer containing styrene monomer units. Patent Document 2 discloses a styrenic resin composition containing 0.1 to 15% by mass of a biomass plasticizer having a biomass carbon ratio (pMC%) of 10% or more.

Styrene resin has a wider melting temperature range than other thermoplastic resins, and the molding temperature can be set depending on the viscosity of the resin and the shape of the molded product. However, when the molding temperature is raised, volatile components are more likely to be generated from the resin, resulting in mold stains during injection molding and eye stains during sheet molding. In addition, if the molding temperature is high, the resin will burn inside the molding machine cylinder and tend to become yellowish. Furthermore, when molding is performed on an industrial scale, a higher molding temperature consumes more power than a lower molding temperature, which is undesirable from an economical and environmental standpoint. Therefore, a resin that can be molded at low temperatures is required. For example, Patent Document 3 discloses a styrenic resin composition with excellent low-temperature moldability. Moreover, Patent Document 4 discloses a resin composition for sheet molding that can be subjected to secondary processing by low temperature molding after sheet molding.

Japanese Patent Application Publication No. 2016-199652 International Publication No. 2022/114221 Japanese Patent Application Publication No. 2009-256502 Japanese Patent Application Publication No. 11-228777

The technology of Patent Document 1 above considers a polymer alloy of styrene-based resin and polylactic acid, which has a relatively high melting point, toughness, and transparency among plant-derived biodegradable polymers; Since the compatibility of polylactic acid with resin is very low, there is a problem in that it is difficult to design a product that satisfies the impact resistance or elasticity required in the market. Furthermore, since polylactic acid is incompatible with styrene resin, there is also the problem that it is difficult to recycle the scrap material. Furthermore, since polylactic acid is not a plasticizer, it is not effective in improving the fluidity of styrenic resins. Therefore, alloys of polylactic acid and styrene resins have low fluidity and are difficult to mold at low temperatures.

In the technique of Patent Document 2, a styrene resin composition containing 0.1 to 15% by mass of a biomass plasticizer with a biomass carbon ratio (pMC%) of 10% or more is considered, but the content is 0.1% to 15% by mass. In the case of 1 to 15% by mass, it is difficult to significantly lower the molding temperature, so there is a problem that yellowing increases due to resin burning during melting and kneading in the cylinder of the molding machine or in the extruder. In addition, mold stains and sheet stains may occur due to volatile components during molding.

In the technique of Patent Document 3, a styrene resin composition containing a styrene resin and a flame retardant and having a melt mass flow rate of 4.0 to 10.0 g/min at 200°C is considered. Since the mass flow rate is within the range of common styrenic resins, it is thought that low-temperature moldability is insufficient. Also, it does not contain biomass materials that reduce environmental impact.

The technique disclosed in Patent Document 4 considers a sheet-molding resin composition in which liquid paraffin is added to a rubber-modified styrene resin. However, liquid paraffin has poor compatibility with styrenic resins, and bleed-out becomes a problem when the content is high. In addition, liquid paraffin volatilizes during injection molding or sheet molding, and there are concerns that it may worsen mold staining of the injection molding machine and cause sheet grain stains. Additionally, it does not contain biomass materials that reduce environmental impact.
Therefore, Patent Documents 1 to 4 do not consider styrenic resins using biomass raw materials that reduce environmental impact, have excellent mechanical strength, and can be molded at low temperatures.
Therefore, an object of the present disclosure is to provide a styrenic resin composition that uses biomass raw materials, reduces environmental impact, has excellent mechanical strength, and can be molded at low temperatures, and a molded product thereof.

In view of the above problems, as a result of intensive research and repeated experiments, the present inventors have discovered that a styrene resin (A) and a biomass plasticizer (B) having a high boiling point biomass carbon ratio (pMC%) of 10% or more ) It was discovered that the above-mentioned problems could be solved by using a styrene-based resin composition mixed in a specific ratio, and the present invention was completed.

上記表１の検討の結果を踏まえて、スチレン系樹脂組成物のブリードアウト・熱による成形品の収縮、変形等が顕著になる現象が生じた場合、当該バイオマス可塑剤（Ｂ）のＳＰ値とスチレン系樹脂（Ａ）のＳＰ値とを特定の範囲内に制御することがより好ましい。
当該バイオマス可塑剤（Ｂ）のＳＰ値とスチレン系樹脂（Ａ）のＳＰ値とが特定の範囲であると、両者の相溶性が高まり、バイオマス可塑剤（Ｂ）の含有量を上げてもブリードアウトが起こらず生産可能であることを見出した。 [Change in morphology depending on biomass plasticizer (B) content]
In particular, if the compatibility between the biomass plasticizer (B) with a biomass carbon ratio (pMC%) of 10% or more and the styrene resin (A) is low, the content of the biomass plasticizer (B) in the entire styrenic resin composition When the amount was increased, bleed-out etc. became noticeable in the composition, making production difficult in some cases. Therefore, changes in the physical properties (morphology, shear viscosity) of the styrenic resin composition at each content of the biomass plasticizer (B) were investigated as follows.
When the content of the biomass plasticizer (B) exceeds 15% by mass, it becomes difficult for the styrene resin (A) and the biomass plasticizer (B) to be completely compatible with each other, resulting in a change in morphology. As a result, when the content of biomass plasticizer (B) is 15% by mass or less, the Vicat softening temperature, which indicates heat resistance, decreases linearly as the content decreases, but when it exceeds 15% by mass, the biomass plasticizer (B) It has been confirmed that even if the content of (B) is increased, the degree of decrease in the Vicat softening temperature becomes smaller. On the other hand, it has been confirmed that the shear viscosity (180° C., 1000/sec) at the same temperature decreases as the content of the biomass plasticizer (B) increases. Therefore, when the content of the biomass plasticizer (B) increases to more than 15% by mass, the heat resistance of the entire composition is maintained while molding at a lower temperature becomes possible. Table 1 shows the relationship between the shear viscosity (180° C., 1000/sec) and Vicat softening temperature with respect to the content of biomass plasticizer (B).
By maintaining the heat resistance of the entire composition, it is possible to maintain the shape of the molded product without shrinking or deforming it due to heat during transportation or during the coloring and drying process.

Based on the results of the study in Table 1 above, if phenomena such as bleed-out of the styrenic resin composition, shrinkage or deformation of the molded product due to heat occur, the SP value of the biomass plasticizer (B) It is more preferable to control the SP value of the styrene resin (A) within a specific range.
When the SP value of the biomass plasticizer (B) and the SP value of the styrene resin (A) are within a specific range, the compatibility between the two increases, and even if the content of the biomass plasticizer (B) is increased, bleeding will not occur. It was found that production was possible without occurrence of out-of-use.

The invention is as follows.
(1) The present disclosure comprises 30 to 84.9 mass % of a styrenic resin (A) containing styrene monomer units and 15 mass % of a biomass plasticizer (B) having a biomass carbon ratio (pMC%) of 10% or more. % to 70% by mass or less.

(2) In the styrenic resin composition of the present embodiment, the Vicat softening temperature of the styrenic resin composition is preferably 65° C. or lower.

(3) In the styrenic resin composition of the present embodiment, it is preferable that the melt viscosity of the styrene resin composition measured at a resin temperature of 180° C. and a shear rate of 1000/sec is 140 (Pa·sec) or less.

(4) In the styrenic resin composition of the present embodiment, it is preferable that the melt viscosity of the styrene resin composition measured at a resin temperature of 180° C. and a shear rate of 40/sec is 1200 (Pa·sec) or less.

(5) In the styrenic resin composition of the present embodiment, the styrenic resin (A) includes a polymer matrix phase containing the styrenic polymer (a-1) containing the styrenic monomer unit as a constituent component; A rubber-modified styrenic resin containing rubbery polymer particles (a-2),
The absolute value of the difference between the SP value of the styrenic polymer (a-1) and the SP value of the biomass plasticizer (B) is preferably less than 2.5 (cal/cm ³ ) ^1/2 . .

(6) In the styrenic resin composition of the present embodiment, the SP value of the biomass plasticizer (B) is preferably 7.4 to 10.5 (cal/cm ³ ) ^1/2 .

(7) In the styrenic resin composition of the present embodiment, the SP value of the styrenic polymer (a-1) is preferably 7.0 to 11.0 (cal/cm ³ ) ^1/2 .

(8) In the styrenic resin composition of the present embodiment, the styrenic resin (A) includes a polymer matrix phase containing a styrenic polymer (a-1) and rubber-like polymer particles (a-2). ) is a rubber-modified styrenic resin containing
and the content of the rubbery polymer particles (a-2) is 2 to 40% by mass with respect to the total amount (100% by mass) of the styrenic resin (A), and the content of the rubbery polymer particles (a- The average particle diameter of 2) is preferably 0.3 to 7.0 μm.

(9) In the styrenic resin composition of the present embodiment, the content of the styrenic monomer units contained in the styrenic polymer (a-1) is higher than that of the styrenic polymer (a-1). It is preferably 50% by mass or more based on the total amount (100% by mass).

(10) This embodiment is an injection molded article obtained by injection molding the styrenic resin composition according to any one of (1) to (9) above.

(11) This embodiment is a sheet made of the styrenic resin composition according to any one of (1) to (9) above.

According to the present invention, there is provided a styrenic resin composition and a molded article thereof that can be molded at low temperature while reducing environmental load and maintaining high mechanical strength by using biomass raw materials.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "this embodiment") will be described in detail, but the present invention is not limited to the following description, and can be modified in various ways within the scope of the gist. It can be implemented by

[Styrenic resin composition]
The styrenic resin composition according to the present embodiment includes 30 to 84.9% by mass of a styrenic resin (A) containing styrene monomer units, and a biomass plasticizer having a biomass carbon ratio (pMC%) of 10% or more. (B) more than 15% by mass to 70% by mass.
Thereby, it is possible to provide a styrenic resin composition that can be molded at low temperatures and has a reduced environmental load and high mechanical strength during molding.
Further properties may be imparted to the styrenic resin composition depending on the intended use. For example, one of the preferable aspects of the styrenic resin composition of the present embodiment is that when high mechanical strength is important, the styrenic resin composition has rubbery polymer particles (hereinafter referred to as rubbery polymer particles (a)). -2)).
When the styrenic resin composition of the present embodiment contains rubbery polymer particles (a-2), the rubbery polymer particles (a-2) such as so-called MBS resin particles are used as the styrene resin (A). Further, in an embodiment in which the styrenic resin (A) contains rubber-like polymer particles (a-2) dispersed in a styrenic polymer (a-1) containing styrene monomer units as a polymer matrix phase. Examples include an embodiment in which a rubber-modified styrenic resin is used.

"Form containing rubbery polymer particles (a-2)"
A preferred styrenic resin composition of the present disclosure includes 30 to 84.9% by mass of a styrenic resin (A) containing styrenic monomer units, and a biomass plasticizer (A) having a biomass carbon ratio (pMC%) of 10% or more. B) more than 15% by mass to 70% by mass, and the styrenic resin (A) is a polymer matrix whose constituent component is the styrenic polymer (a-1) containing the styrenic monomer unit. It may be a rubber-modified styrenic resin containing a phase and rubbery polymer particles (a-2).
In other words, the styrenic resin composition of the present embodiment contains 30 to 84.9% by mass of the rubber-modified styrenic resin and 15% of the biomass plasticizer (B) based on the entire styrenic resin composition (100% by mass). The rubber-modified styrenic resin contains a polymer matrix phase and rubber-like polymer particles ( a-2).
This makes it possible to provide a styrenic resin composition with reduced environmental impact, higher mechanical strength, and superior properties.

<Rubber-modified styrene resin>
The styrenic resin composition in this embodiment may contain a rubber-modified styrenic resin. In the present embodiment, the content of the rubber-modified styrenic resin is 30 to 84.9% by mass with respect to the entire styrenic resin composition (100% by mass), and the lower limit is 35% by mass or more. Preferably, more preferably 40% by mass or more, even more preferably 45% by mass or more, even more preferably 47.5% by mass or more, even more preferably 50% by mass or more, even more preferably 52.5% by mass or more, Still more preferably 55% by mass or more, even more preferably 57.5% by mass or more, even more preferably 60% by mass or more. The upper limit is preferably 82.5% by mass or less, more preferably 80% by mass or less, even more preferably 78% by mass or less, even more preferably 76% by mass or less. By setting the content to 30% by mass or more, impact resistance is improved. On the other hand, by setting the content to 84.9% by mass or less, fluidity can be improved and low-temperature moldability can be improved.

In the present embodiment, the rubber-modified styrenic resin refers to rubber-like polymer particles (a-2) dispersed in a styrenic polymer (a-1) containing styrenic monomer units as a polymer matrix phase. It can be produced by polymerizing styrenic monomers in the presence of a rubbery polymer.

-Polymer matrix phase-
The polymer matrix phase of the rubber-modified styrenic resin of this embodiment is preferably composed of a styrenic polymer (a-1) containing styrenic monomer units. The monomer units constituting the styrenic polymer (a-1) of this embodiment include vinyl which essentially contains a styrenic monomer unit and is copolymerizable with the styrenic monomer unit if necessary. It is preferable to contain the monomer unit (i). Therefore, the styrenic polymer (a-1) is preferably one or more selected from the group consisting of polystyrene and styrene copolymer resins. As described below, examples of the styrene-based copolymer resin include styrene-(meth)acrylic acid ester copolymer.
Note that "consisting" means that 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more of the total amount of the polymer matrix phase is occupied by the styrenic polymer (a-1). means.
Among the monomer units constituting the styrenic polymer (a-1) of the present embodiment, the content of styrenic monomer units is 50 to 50% relative to the entire styrenic polymer (a-1). It is preferably 100% by weight, more preferably 60 to 100% by weight, even more preferably 70 to 100% by weight, even more preferably 80 to 100% by weight, even more preferably 90 to 100% by weight. The content of the styrenic monomer unit in the styrenic polymer (a-1) and the vinyl monomer unit (i) that can be copolymerized with a styrenic monomer other than the styrenic monomer unit is , each can be determined from the integral ratio of the spectrum measured with a proton nuclear magnetic resonance ( ¹ H-NMR) measuring device.
In addition to styrene, examples of the styrenic monomer in this embodiment include α-methylstyrene, α-methylp-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, Examples include ethylstyrene, isobutylstyrene, and t-butylstyrene or styrene derivatives such as bromostyrene and indene. In particular, styrene is preferred. These styrene monomers may be used alone or in combination of two or more.

In this embodiment, the vinyl monomer (i) is one or more selected from the group consisting of unsaturated carboxylic acid monomers and unsaturated carboxylic acid ester monomer units. is preferable, and examples thereof include, but are not limited to, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and cyclohexyl (meth)acrylate. etc. These monomers can be used alone or in combination of two or more.
Note that the term "(meth)acrylic acid" includes both acrylic acid and methacrylic acid.

--polystyrene--
In this embodiment, polystyrene is a homopolymer obtained by polymerizing styrene monomers, and commonly available polystyrene can be appropriately selected and used. The styrene monomers constituting polystyrene are the same as the above styrene monomers, and include styrene, α-methylstyrene, α-methyl-p-methylstyrene, o-methylstyrene, m-methylstyrene, and p-methylstyrene. - Styrene derivatives such as methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and t-butylstyrene or bromostyrene and indene. Styrene is particularly preferred from an industrial standpoint. These styrene monomers can be used alone or in combination of two or more. The polystyrene typically consists of styrene monomer units, although it is not excluded that the polystyrene may further contain monomer units other than the above-mentioned styrene monomer units as long as the effects of the present invention are not impaired.

--Styrenic copolymer resin--
In the present embodiment, the styrenic copolymer resin is preferably a resin containing a styrene monomer unit and a vinyl monomer unit (i), and a styrenic monomer unit and an unsaturated carboxylic acid. It is more preferable that the resin contains one or more monomer units selected from the group consisting of a monomer unit and an unsaturated carboxylic acid ester monomer unit, and a styrenic monomer unit. More preferably, it is a resin containing an unsaturated carboxylic acid ester monomer unit.
The styrenic copolymer resin in the present invention has styrene monomer units, when the total content of styrene monomer units, unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units is 100% by mass. The content of mer units is preferably in the range of 51 to 98% by weight, more preferably 54 to 96% by weight, more preferably 57 to 93% by weight, and even more preferably 60 to 90% by weight. By setting the content to 51% by mass or more, the refractive index of the styrene resin (A) can be improved. On the other hand, by setting the content to 98% by mass or less, it becomes difficult to make the desired amount of unsaturated carboxylic acid ester monomer units exist.
In another aspect, when the total content of styrene monomer units, unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units is 100% by mass, styrene monomer units The preferred content range may be 69 to 98% by weight, 74 to 96% by weight, and 77 to 92% by weight.
In addition, the styrenic copolymer resin in the present invention has a total content of styrene monomer units, unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units as 100% by mass, The content of unsaturated carboxylic acid ester monomer units is preferably 2 to 49% by mass, more preferably 4 to 46% by mass, more preferably 7 to 43% by mass, even more preferably 10% by mass. It is in the range of ~40% by mass. In another embodiment, when the total content of the styrene monomer units and the unsaturated carboxylic ester monomer units is 100% by mass, the preferred content range of the unsaturated carboxylic ester monomer units may be from 2 to 31% by weight, from 4 to 26% by weight, and from 8 to 23% by weight.
The styrenic copolymer resin in the present invention has an unsaturated The content of carboxylic acid monomer units is preferably in the range of 0 to 20% by weight, more preferably in the range of 0 to 15% by weight, even more preferably in the range of 0 to 13% by weight.
In this embodiment, styrene monomer units (e.g., styrene monomer units), unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units (e.g., methacrylate monomer units) in the styrenic copolymer resin The content of methyl acid monomer units) can be determined from the integral ratio of the spectrum measured with a proton nuclear magnetic resonance ( ¹ H-NMR) measuring device.

Specific examples of the styrene monomer constituting the styrenic copolymer resin of this embodiment are the same as the styrene monomers described above, and will therefore be omitted.
The unsaturated carboxylic acid ester monomer constituting the styrene copolymer resin of this embodiment is not particularly limited, but examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, Examples include butyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like. As the (meth)acrylic acid ester monomer, methyl (meth)acrylate is preferred because it has a small effect on heat resistance deterioration. These unsaturated carboxylic acid ester monomers can be used alone or in combination of two or more.
The unsaturated carboxylic acid monomer constituting the styrene copolymer resin of this embodiment is not particularly limited, but (meth)acrylic acid is preferred.

The styrene copolymer resin of this embodiment includes styrene-methyl (meth)acrylate copolymer, styrene-ethyl (meth)acrylate copolymer, styrene-propane (meth)acrylate copolymer, or styrene-methyl (meth)acrylate copolymer. -Butyl (meth)acrylate copolymer and styrene-methyl (meth)acrylate-butyl meth)acrylate copolymer are preferred.

In this embodiment, the weight average molecular weight (Mw) of the styrenic copolymer resin is preferably 100,000 to 400,000, more preferably 120,000 to 390,000, even more preferably 140,000 to 380. ,000. When the weight average molecular weight (Mw) is 100,000 to 400,000, a resin with an excellent balance between mechanical strength and fluidity can be obtained, and there is also less contamination of gel substances. Further, in another form of this embodiment, when emphasis is placed on mouth impact strength and buckling strength, the weight average molecular weight (Mw) of the styrenic copolymer resin is preferably 100,000 to 300,000, More preferably 120,000 to 260,000, still more preferably 140,000 to 240,000, even more preferably 150,000 to 230,000. Note that the weight average molecular weight (Mw) is a value obtained in terms of standard polystyrene using gel permeation chromatography.

The styrenic resin (A) in this embodiment may be any resin containing a styrene monomer unit, and may contain a resin containing two or more different styrene monomer units. For example, the styrene resin (A) may be a mixture of one or more of the polystyrenes and one or more of the styrene copolymer resins, It may be a mixture of two or more kinds and one or more kinds of the above rubber-modified styrenic resins. In addition, the styrenic resin (A) in this embodiment is a mixture of one or more of the above rubber-modified styrenic resins and one or more styrene copolymer resins. Good too. In that case, the mixing ratio of the rubber-modified styrene resin and the styrene copolymer resin can be changed as appropriate depending on the purpose of use. For example, in a system in which the rubber-modified styrene-based resin is greater than the styrene-based copolymer resin, the styrene-based copolymer resin is contained in an amount of 0.1 to 30% by mass based on the total amount (100% by mass) of the styrene-based resin (A). It is preferable to do so. On the other hand, in systems where the rubber-modified styrene resin is less than the styrene copolymer resin, the styrene copolymer resin is contained in an amount of 70 to 99.9% by mass based on the total amount (100% by mass) of the styrene resin (A). It is preferable to do so.

In this embodiment, the styrenic polymer (a-1) or the styrenic resin composition of this embodiment contains vinyl cyanide monomers such as acronitrile monomer units and methacrylonitrile monomer units. Preferably, it does not substantially contain. Specifically, the vinyl cyanide monomer preferably contains 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the styrene polymer (a-1) or the polymer matrix. Preferably, the content is more preferably 2% by mass or less.

The content of the styrenic polymer (a-1) of the present embodiment is preferably 10 to 82.9% by mass, more preferably 15 to 80% by mass, based on the entire styrenic resin composition (100% by mass). , 20 to 75% by weight, more preferably 25 to 70% by weight, even more preferably 30 to 65% by weight.

-Rubber-like polymer-
In the styrenic resin composition of this embodiment, the rubbery polymer particles (a-2) may be contained in the styrenic resin composition as a part of the rubber-modified styrenic resin, or the styrenic polymer particles (a-2) may be contained in the styrenic resin composition as a part of the rubber-modified styrenic resin. -1), rubber-like polymer particles (a-2) different from the rubber-like polymer particles (a-2) contained in the rubber-modified styrenic resin are further blended into the styrenic resin composition. May be included.
The rubber-like polymer particles (a-2) contained in the rubber-modified styrenic resin of this embodiment may include, for example, the styrenic polymer (a-1) on the inside and/or the styrene polymer on the outside. The system polymer (a-1) may be grafted. Furthermore, the rubbery polymer particles (a-2) of the present embodiment are composed of a styrene polymer (a-1) as a core and a rubbery polymer as a shell that encompasses the core. Not only a core-shell structure but also a styrenic polymer (a-1) as a plurality of cores and a rubber-like polymer as a shell that encompasses the styrenic polymer (a-1) as the plurality of cores. comprising a salami structure.

Examples of the rubbery polymer or rubbery polymer particles (a-2) of the present embodiment or the material of the rubbery polymer include polybutadiene, polybutadiene containing polystyrene, polyisoprene, natural rubber, polychloroprene, and styrene. Butadiene copolymers, acrylonitrile-butadiene copolymers, and the like can be used, but polybutadiene or styrene-butadiene copolymers are preferred. As the polybutadiene, both high-cis polybutadiene with a high cis content and low-cis polybutadiene with a low cis content can be used. Further, as the structure of the styrene-butadiene copolymer, both a random structure and a block structure can be used. These rubbery polymers may be used alone or in combination of two or more. It is also possible to use a saturated rubber obtained by hydrogenating butadiene rubber.
Examples of such rubber-modified styrenic resins include HIPS (high impact polystyrene), ABS resin (acrylonitrile-butadiene-styrene copolymer), AES (acrylonitrile-ethylenepropylene rubber-styrene copolymer), etc. .

In the present embodiment, the content of the rubber-like polymer contained in the rubber-modified styrenic resin (the content of the rubber-like polymer (for example, a conjugated diene-based polymer such as polybutadiene) itself, and the content of the rubber-like polymer particles ( The styrenic polymer (a-1) included in a-2) is not included.) is 1.0 to 15% by mass based on the total amount (100% by mass) of the rubber-modified styrenic resin. More preferably, it is 1.2 to 12% by weight, still more preferably 1.5 to 11% by weight, even more preferably 2.0 to 10% by weight, and even more preferably 3 to 9.0% by weight. If the content of the rubbery polymer is less than 1.0% by mass, there is a risk that the impact resistance of the entire styrenic resin composition will decrease. Furthermore, if the content of the rubbery polymer exceeds 15% by mass, there is a risk that the fluidity of the entire styrenic resin composition will decrease.
Note that in the present disclosure, the content of the rubbery polymer contained in the rubber-modified styrenic resin is a value calculated using the method described in the Examples section.

In this embodiment, the content of the rubber-like polymer particles (a-2) contained in the rubber-modified styrene-based resin (the content of the rubber-like polymer (for example, a conjugated diene-based polymer such as polybutadiene) itself, and the rubber (including the content of the styrenic polymer (a-1) contained within the styrene-based polymer particles (a-2)) is 2 to 2% based on the entire styrene resin composition (100% by mass) 40% by mass is preferred, 3 to 36% by mass is more preferred, even more preferably 4 to 32% by mass, even more preferably 5 to 30% by mass, even more preferably 6 to 28% by mass, even more preferably It is 7 to 26% by mass.

In this embodiment, the average particle diameter of the rubbery polymer particles (a-2) contained in the rubber-modified styrenic resin is preferably 0.3 to 7.0 μm, more preferably 0.4 to 5 μm. .0 μm, more preferably 0.5 to 3.5 μm, and from the viewpoint of impact resistance preferably 0.8 to 3.5 μm, more preferably 0.8 to 3.0 μm.
In addition, in the present disclosure, the average particle diameter of the rubbery polymer particles (a-2) contained in the rubber-modified styrenic resin is a value calculated by the method described in the Examples column or the following method. .
Using COULTER MULTISIZER III (trade name) manufactured by Beckman Coulter Inc. equipped with an aperture tube with a diameter of 30 μm, 0.05 g of rubber-modified styrenic resin pellets were placed in about 5 ml of dimethylformamide and left for about 2 to 5 minutes. Next, the dimethylformamide dissolved content was measured as an appropriate particle concentration, and the volume-based median diameter was defined as the average particle diameter. In addition, the method for measuring the average particle size of the rubbery polymer particles (a-2) described above may be applied to the method for measuring the average particle size of the rubbery polymer particles (a-2) contained in the entire styrenic resin composition. can.

In this embodiment, the reduced viscosity of the styrenic polymer (a-1) contained in the rubber-modified styrenic resin (this is an indicator of the molecular weight of the styrenic polymer (a-1)) is 0. It is preferably in the range of .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.
Note that in the present disclosure, the reduced viscosity of the styrenic polymer (a-1) is a value measured in a toluene solution at 30° C. and a concentration of 0.5 g/dL.

In this embodiment, when the styrenic resin (A) is a rubber-modified styrenic resin (HIPS resin), polybutadiene and styrene-butadiene rubber are particularly preferable among these rubbery polymers, and polybutadiene is particularly preferable among these rubber-like polymers. is the most preferred.

-Production method of rubber modified styrenic resin-
In this embodiment, the method for producing the rubber-modified styrenic resin is not particularly limited, but in the presence of a rubbery polymer, a styrene monomer, a vinyl monomer (i.e. ) and a solvent added if necessary, bulk polymerization (or solution polymerization), or bulk-suspension polymerization, which transitions to suspension polymerization during the reaction, or styrenic monomer in the presence of a rubbery polymer latex. It can be produced by emulsion graft polymerization in which vinyl monomer (i) is added as necessary. In bulk polymerization, a rubbery polymer, a styrene monomer, a vinyl monomer (i) added as necessary, and an organic solvent, an organic peroxide, and/or a chain transfer agent as necessary are added. It can be produced by continuously supplying the added mixed solution to a polymerization apparatus configured by connecting a complete mixing reactor or a tank reactor and a plurality of tank reactors in series.

In this embodiment, the polymerization method of the styrenic polymer (a-1), which is the polymer matrix phase of the rubber-modified styrenic resin, is not particularly limited, but for example, as a radical polymerization method, a bulk polymerization method or a solution polymerization method can be suitably employed. The polymerization method mainly includes a polymerization step in which a polymerization raw material (monomer component) is polymerized, and a devolatilization step in which volatile components such as unreacted monomers and polymerization solvents are removed from the polymerization product.

-Production method of styrenic copolymer resin-
In this embodiment, the polymerization method of the styrene-based copolymer resin is not particularly limited, but for example, as a radical polymerization method, a bulk polymerization method or a solution polymerization method can be suitably employed. The polymerization method mainly includes a polymerization step in which a polymerization raw material (monomer component) is polymerized, and a devolatilization step in which volatile components such as unreacted monomers and polymerization solvents are removed from the polymerization product.
An example of a method for polymerizing a styrenic copolymer resin that can be used in this embodiment will be described below.
When a polymerization raw material is polymerized to obtain the styrene-based copolymer resin, a polymerization initiator and a chain transfer agent are typically contained in the polymerization raw material composition.
Polymerization initiators used in the polymerization of styrenic copolymer resins include organic peroxides, such as 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane (perhexane), and 1,1-bis(t-butylperoxy)cyclohexane. C), peroxyketals such as n-butyl-4,4-bis(t-butylperoxy)valerate, dialkyl peroxides such as di-t-butyl peroxide (perbutyl D), t-butylcumyl peroxide, dicumyl peroxide, etc. diacyl peroxides such as acetyl peroxide and isobutyryl peroxide, peroxydicarbonates such as diisopropyl peroxydicarbonate, peroxy esters such as t-butyl peroxyacetate, ketone peroxides such as acetylacetone peroxide, t-butyl hydroperoxide Examples include hydroperoxides such as. From the viewpoint of decomposition rate and polymerization rate, 1,1-bis(t-butylperoxy)cyclohexane is particularly preferred. It is preferable to add 0.005 to 0.08% by mass based on the total amount of monomers.
Examples of chain transfer agents used in the polymerization of styrene-based copolymer resins include mercaptans such as n-dodecylmercaptan, t-dodecylmercaptan, and n-octylmercaptan, α-methylstyrene linear dimer, 1-phenyl-2- Examples include fluorene, dibentene, chloroform, terpenes, halogen compounds, and turpentines such as terepinolene. The amount of this chain transfer agent to be used is not particularly limited, but it is generally preferable to add it in an amount of about 0.005 to 0.3% by weight based on the monomer.
The above polymerization initiator and chain transfer agent can be used not only in the production of the styrenic copolymer resin but also in the production of the rubber-modified styrenic resin.

As a method for polymerizing the styrene-based copolymer resin, solution polymerization using a polymerization solvent can be employed, if necessary. Examples of the polymerization solvent used include aromatic hydrocarbons such as ethylbenzene, dialkyl ketones such as methyl ethyl ketone, and each 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 within a range that does not reduce the solubility of the polymerization product. It is preferable to use these polymerization solvents in an amount not exceeding 25 parts by mass based on 100 parts by mass of the total monomers. When the polymerization solvent exceeds 25 parts by mass based on 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. It is preferable to add it at a ratio of 5 to 20 parts by mass per 100 parts by mass of the total monomers before polymerization, because quality can be easily uniformized and polymerization temperature can be controlled.

In the present embodiment, the apparatus used in the polymerization step to obtain the styrene copolymer resin is not particularly limited, and may be appropriately selected according to a general method for polymerizing styrenic resins. For example, when bulk polymerization is employed, a polymerization apparatus in which one or more complete mixing reactors are connected can be used. There is also no particular restriction on the devolatilization step. For example, when bulk polymerization is employed, the polymerization is continued until the unreacted monomer is preferably 50% by mass or less, more preferably 40% by mass or less, and volatile components such as the unreacted monomer are removed. Then, devolatilization treatment is performed using a known method. More specifically, for example, a normal devolatilizing device such as a flash drum, a twin-screw devolatilizer, a thin film evaporator, an extruder, etc. can be used, but a devolatilizing device with a small number of retention parts is preferable. Note that the temperature of the devolatilization treatment is usually about 190 to 280°C, more preferably 190 to 260°C. The pressure for the devolatilization treatment is usually about 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, and more preferably 0.13 to 2.0 kPa. Preferred methods of devolatilization include, for example, a method in which volatile components are removed under reduced pressure under heating, and a method in which volatile components are removed through an extruder or the like designed for the purpose of removing volatile components.

<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, it is possible to reduce the amount of fossil fuel used, so it is possible to provide a styrenic resin composition that can reduce environmental load.
In one form of the present embodiment, the lower limit of the biomass carbon ratio (pMC%) is preferably 10% or more, more preferably 25% or more, even more preferably 50% or more, and even more preferably 75% or more.
In addition, "plasticizer" in this specification is mainly a low-molecular substance with a molecular weight of less than 10,000, and when added to styrene resin, etc., the resin is modified, improving fluidity, impact resistance, expansion and contraction. Refers to a group of compounds that have the effect of improving sexual performance, etc.

In the present embodiment, the content of the biomass plasticizer (B) is more than 15% by mass to 70% by mass with respect to the total amount (100% by mass) of the styrenic resin composition. The lower limit of the content of the biomass plasticizer (B) is preferably 16% by mass or more, more preferably 17% by mass or more, more preferably 18% by mass or more, even more preferably 19% by mass or more. The upper limit of the content of the biomass plasticizer (B) is preferably 70% by mass or less, more preferably 65% by mass or less, even more preferably 60% by mass or less, even more preferably 55% by mass or less, and even more preferably 52.5% by mass or less, even more preferably 50% by mass or less, even more preferably 47.5% by mass or less, even more preferably 45% by mass or less, even more preferably 42.5% by mass or less, even more preferably is 40% by mass or less.
If the content of the biomass plasticizer (B) is too large, bleed-out tends to occur depending on the difference in SP value between the styrene resin (A) and the biomass plasticizer (B). In addition, the molded product becomes soft and easily deforms. On the other hand, if the content of the biomass plasticizer (B) is too small, the fluidity will be lowered, so the molding temperature will increase, and there are concerns about problems such as mold stains, sheet stains, and resin burns.
Methods for incorporating the biomass plasticizer (B) into the styrenic resin composition include a method of kneading the styrenic resin (A) (for example, rubber-modified styrenic resin) and the biomass plasticizer (B) in an extruder; , a method of incorporating a biomass plasticizer (B) into the polymerization raw material composition when polymerizing the polymerization raw material, and the like.

The biomass carbon ratio (pMC%) in this specification indicates the carbon concentration (mass ratio) of biomass-derived components, and more specifically, the biomass carbon ratio (pMC%) is determined by the radioactive carbon ( ¹⁴ C) measurement method based on ASTM-D6866. This is the value of the ¹⁴ C content obtained. This method of measuring radioactive carbon ( ^14C ) takes advantage of the fact that fossil fuels do not contain ^14C and that carbon derived from biomass (or living things) absorbs ^14C in the atmosphere during the growing period. This is a method for estimating the biomass carbon ratio (pMC%) from the ¹⁴ C ratio in carbon contained in materials (or organisms).
Therefore, by measuring the proportion of C ¹⁴ contained in all carbon atoms in the plasticizer of this embodiment, the proportion of carbon derived from biomass 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 material / ¹² C standard material) × 100
Further, oxalic acid (SRM4990) was used as a standard substance, and ( ^14C plasticizer/ ^12C plasticizer)/( ^14C standard substance/ ^12C 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 to 7,500, more preferably 300 to 5,000, even more preferably 400 to 3,000. When the weight average molecular weight (Mw) of the biomass plasticizer (B) is 200 to 7,500, a styrenic resin composition with an excellent balance between mechanical strength and fluidity can be obtained, and there is also less contamination of gel substances. The weight average molecular weight (Mw) is a value obtained in terms of standard polystyrene using gel permeation chromatography, as described in the Examples section below.

The biomass plasticizer (B) in this embodiment refers to a plasticizer that uses biomass material 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 this embodiment is a plasticizer that uses plant-derived biomass material as at least a part of the raw material and has a biomass carbon ratio (pMC%) of 10% or more, and includes vegetable oil, vegetable oil, and mineral oil. or a polyester plasticizer, which is preferably a natural vegetable oil, a modified vegetable oil, a mixture of a natural vegetable oil and a mineral oil, a mixture of a modified vegetable oil and a mineral oil, a mixture of a natural vegetable oil, a modified vegetable oil, and a mineral oil, or a polyester plasticizer. A plasticizer is more preferable.
Note that the vegetable oil in this specification is a general term for oils and fats derived from plants, 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, and more specifically, it is a hydrocarbon oil of vegetable origin that has been partially modified with a functional group. It is preferable that the The vegetable oils include triesters of glycerin and fatty acids, fatty acid monoesters obtained by adding monoalcohol to vegetable oil and transesterifying them, fatty acid monoesters obtained by esterifying fatty acids and monoalcohols, and fatty acid monoesters obtained by esterifying fatty acids and monoalcohols. Contains derived ethers.
The modifying group (epoxy group, amino group, or ester bond functional group) of the modified vegetable oil in this embodiment is substantially different from other components (including styrenic resin (A)) or modified vegetable oils in the styrenic resin composition. It is preferable not to polymerize. Further, in the present embodiment, it is preferable that the modification rate of the modified vegetable oil per 1 g of the modified vegetable oil is 1 mmol% to 50 mmol%.
The modification rate of the modified vegetable oil is calculated by ¹ H-NMR measurement method as described in Examples below.

Specific examples of the above-mentioned natural vegetable oils include cottonseed oil, tung 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 tonsil 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, canola seed oil, cottonseed oil, coconut oil, pumpkin seed oil, wheat germ oil, jojoba oil, lily oil, macadamia oil, corn oil, medfoam oil, monoi oil, hazelnut oil, apricot kernel oil, walnut oil, olive oil, evening primrose oil, palm oil, blackcurrant seed oil, kiwi seed oil, grapeseed oil, pistachio oil, musk oil, sesame oil, soybean oil, sunflower oil, castor oil, watermelon oil or mixtures of these oils.
In this embodiment, the modified vegetable oils include oil obtained by hydrogenating the natural vegetable oils exemplified above (for example, hydrogenated castor oil); oils obtained by epoxidizing the natural vegetable oils exemplified above (for example, modified epoxidized oil); Examples include oils obtained by aminating vegetable oils (eg, modified aminated oils). The 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 this embodiment include palm oil, epoxidized soybean oil, epoxidized linseed oil, hydrogenated castor oil, polyoxyethylated castor oil, polyoxyethylated hydrogenated castor oil, Oleic acid esters or lauric acid esters include "Polysizer W-1810-BIO" and "Eposizer" manufactured by DIC Corporation; "Newsizer 510R" and "Newsizer 512" manufactured by NOF Corporation; and Takemoto Yushi. "Pionin D series" manufactured by Nisshin Oilli Group Co., Ltd.; "Multi Ace 20 (S)" and "refined palm oil (S)" manufactured by Nisshin Oilli Group Co., Ltd.; and "Castor hydrogenated oil" manufactured by Ito Oil Co., Ltd. .

In the present embodiment, the viscosity of the vegetable oil (including natural vegetable oils and modified vegetable oils) is preferably 1000 mPa·s or less at 25°C, and 20 to 1000 mPa·s. s, more preferably 50 to 1000 mPa.s. More preferably, it is 100 to 800 mPa.s. It is even more preferable that it is s.

The biomass plasticizer (B) in this embodiment may be a modified vegetable oil modified with an epoxy group, an amino group, or an ester bond. In this case, the modifying group (epoxy group, amino group, or ester bond functional group) in the biomass plasticizer (B) in this embodiment may be present in other components (styrenic resin (A) as well) in the styrenic resin composition. ) or modified vegetable oils.
The melting point of the biomass plasticizer (B) in this embodiment is preferably -30 to 80°C, more preferably -25 to 77°C, even more preferably -22 to 74°C, even more preferably -18°C. °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 even more preferably More preferably -3°C to 55°C, particularly preferably -1°C to 52°C. If the melting point of the biomass plasticizer (B) is higher than 80°C, the biomass plasticizer (B) will be difficult to melt in the styrene resin (A), making addition or mixing operations 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 a large number of unsaturated bonds as the type of usable biomass plasticizer (B), which may cause oxidative deterioration. It is easy to cause physical properties to deteriorate. 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 this 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, and 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 It is less than 1.2, more preferably less than ±1.1, even more preferably less than ±1.0, even more preferably less than ±0.9, even more preferably less than ±0.8.
If the difference between the SP value of the styrenic polymer (a-1) and the SP value of the biomass plasticizer (B) is ±2.5 or more, it becomes more difficult for the two to be compatible with each other. As a result, if the difference between the SP value of the styrenic polymer (a-1) and the SP value of the biomass plasticizer (B) is large, or if the content of the biomass plasticizer (B) increases, the styrenic resin composition The biomass plasticizer (B) tends to bleed out from inside. Therefore, the styrene resin (A) and the biomass plasticizer (B) become difficult to mix, making production difficult.
Further, the SP value of the styrenic polymer (a-1) in this 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 ), even more preferably 8.0 to 10.0 ((cal/cm ³ ) ^1/2 ), even more preferably 8.0 to 9.8 ((cal/cm ³ ) ^1/2 ), even more preferably 8.0 to 9.6 ((cal/cm ³ ) ^{1 /2} ), even more preferably 8.0 to 9.4 ((cal/cm ³ ) ^1/2 ), even more preferably 8.0 to 9.2 ((cal/cm ³ ) ^1/2 ), Even more preferably it is 8.0 to 9.0 ((cal/cm ³ ) ^1/2 ).
Further, the lower limit of the SP value of the biomass plasticizer (B) in this embodiment is more preferably 7.4 ((cal/cm ³ ) ^1/2 ) or more, and more preferably 7.5 ((cal/cm 3 ) 1/2 ) or more. cm ³ ) ^1/2 ) or more, more preferably 7.6 ((cal/cm ³ ) ^1/2 ), more preferably 7.7 ((cal/cm ³ ) ^1/2 ) or more, even 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), and more preferably 10.3 ((cal/cm ^{3 )} or less. ) 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, in this embodiment, the styrenic polymer (a-1), the styrenic polymer (a-3), and the biomass plasticizer ( A preferable range of the SP value in B) may be a range that is a combination of the above upper limit of the SP value and the lower limit of the above SP value.
The solubility parameter (SP value) defined in this embodiment is calculated using a function of cohesive energy density shown in the following formula.
SP value ((cal/ ^cm3 ) ^1/2 ) = (△E/V) ^1/2 formula (2)
(ΔE indicates the intermolecular cohesive energy (heat of vaporization), V indicates the total volume of the mixed liquid, and ΔE/V indicates the cohesive energy density.)
Further, the change in heat amount ΔHm due to mixing is expressed by the following equation using the SP value.
△Hm=V(δ ₁ - δ ₂ )・Φ1・Φ2 ...Formula (3)
(δ ₁ represents the SP value of the solvent, δ ₂ represents the SP value of the solute, Φ ₁ represents the volume fraction of the solvent, and Φ ₂ represents the volume fraction of the solute.)
From the above equations (2) and (3), the closer the values of δ ₁ and δ ₂ , the smaller ΔHm and the smaller the Gims free energy, so those with a small difference in SP value have less affinity. It gets expensive.
In this specification, the method for determining the SP value is to compare the solubility of the resin with various solvents with known SP values, and calculate the SP value of the unknown resin from the SP value of the most compatible solvent. Specifically, it was calculated using the turbidity titration method described in the Examples section. In the present embodiment, values mainly calculated from the monomer composition are used.
If the biomass plasticizer (B) of this embodiment has a high boiling point, the amount of gas generated during molding will be reduced, which is advantageous in reducing mold fouling. The molding temperature is preferably 260° C. or higher). 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. Show .

If necessary, the styrenic resin composition of this embodiment may contain mineral oil as a mixture of vegetable oil and mineral oil separately from the biomass plasticizer (B), as described above.
In addition, when the biomass plasticizer (B) is a mixture of vegetable oil and mineral oil, it is sufficient that the biomass carbon ratio (pMC%) of the mixture as a whole is 10% or more. Further, when the biomass plasticizer (B) having a biomass carbon ratio (pMC%) of 10% or more is a mixture, the content refers to the total amount of the mixture of vegetable oil and mineral oil.
The mineral oil in this embodiment includes, for example, atmospheric residual oil obtained by atmospheric distillation of crude oil such as paraffinic crude oil (including liquid paraffin), intermediate base crude oil, and naphthenic crude oil; Distillate oil obtained by distilling oil under reduced pressure; the distillate oil is subjected to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining. Obtained mineral oils include mineral oils obtained by isomerizing wax (GTL wax) produced by the Fischer-Tropsch method and the like. These mineral oils may be used alone or in combination of two or more.
In this embodiment, when using a mixture of vegetable oil and mineral oil as the biomass plasticizer (B), there is a particular restriction if the biomass carbon ratio (pMC%) of the entire biomass plasticizer (B) is 10% or more. However, for example, it is preferable to mix 10 to 100 parts by mass, and more preferably 10 to 50 parts by mass, to 100 parts by mass of vegetable oil.
In this embodiment, when using a mixture of vegetable oil and mineral oil as the biomass plasticizer (B), there is a particular restriction if the biomass carbon ratio (pMC%) of the entire biomass plasticizer (B) is 10% or more. Never.

<Optional additional ingredients>
The styrenic resin composition of the present embodiment may optionally contain any additive components other than the above-mentioned (A) and (B) components, such as known additives and processing aids, as long as they do not impair the effects of the present invention. can be added. These additive ingredients include mold release agents, flame retardants, dispersants, antioxidants, weathering agents, antistatic agents, fillers, antiblocking agents, colorants, bluing agents, surface treatment agents, antibacterial agents, and eye stains. Inhibitors (silicone oils described in JP-A-2009-120717, monoamide compounds of higher aliphatic carboxylic acids, monoester compounds obtained by reacting higher aliphatic carboxylic acids with monovalent to trivalent alcohol compounds, etc.) An eye mucus prevention agent) may also be added.
In this embodiment, the styrene-based resin composition may contain a known flame retardant (phosphorus-based flame retardant, halogen-based flame retardant such as bromine-based flame retardant). However, from the viewpoint of concern that gases such as hydrogen bromide may be generated 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, based on the total amount (100% by mass).

It is preferable that the styrenic resin composition in this embodiment does not contain metal elements except for unavoidable impurities. More specifically, the content of the metal element is based on the total amount (100% by mass) of the styrenic resin composition. It is preferably less than 3% by mass, more preferably less than 1% by mass, more preferably less than 0.5% by mass. When a styrenic resin composition contains metal elements, particularly metal particles, not only is the mold used during molding damaged, but there is also a risk that metal powder from the mold will be mixed into the styrenic resin composition.
The above metal elements include elements from Groups 2 to 12 of the Periodic Table of Elements, 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 alone or in the form of an alloy or mixture of two or more types.

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, a fatty acid metal salt, or the like can be used as the dispersant.
As the mold release agent, a fatty acid compound, a fatty acid metal salt, or the like can be used.
Examples of the antioxidant include phenolic compounds, phosphorus compounds, thioether compounds, and the like.
The total content of the optionally added components may be 0.05 to 5% by mass based on the entire styrenic resin composition.

The styrenic resin composition of this embodiment may substantially consist only of component (A), component (B), and optionally added components. Moreover, it may consist only of the (A) component and the (B) component, or only the (A) component, the (B) component, and optionally added components.
More specifically, the styrenic resin composition of the present embodiment contains a styrenic resin (A), a biomass plasticizer (B), and an additive component, and contains the styrenic resin (A), the biomass plasticizer (B), and an additive component. The total content of B) and the additive component is preferably 85 to 100% by mass, more preferably 90 to 100% by mass, even more preferably still more preferably is 95 to 100% by weight, more preferably 98 to 100% by weight, even more preferably 99 to 100% by weight. The additive components include mineral oil, mold release agent, flame retardant, dispersant, antioxidant, weathering agent, antistatic agent, filler, antiblocking agent, coloring agent, blooming agent, surface treatment agent, antibacterial agent, and It is preferable to contain one or more selected from the group consisting of eye stain preventive agents.
The styrenic resin composition of the present embodiment contains a styrene resin (A), a biomass plasticizer (B), and an additive component, and the total content of the styrenic resin (A) and the biomass plasticizer (B) is The amount is preferably 85 to 100% by mass, more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, even more preferably is from 98 to 100% by weight, even more preferably from 99 to 100% by weight. The additive components include mineral oil, mold release agent, flame retardant, dispersant, antioxidant, weathering agent, antistatic agent, filler, antiblocking agent, coloring agent, blooming agent, surface treatment agent, antibacterial agent, and It is preferable to contain one or more selected from the group consisting of eye stain preventive agents.
"Substantially consisting only of component (A), component (B), and additional components" means preferably 85 to 100% by mass, more preferably 90 to 100% by mass, based on the total amount of the styrenic resin composition. , more preferably 95 to 100% by mass, even more preferably 98 to 100% by mass, more preferably 99 to 100% by mass of component (A) and component (B), or component (A) and (B). ) components and optionally added components.
The styrenic resin composition of this embodiment may contain unavoidable impurities in addition to component (A), component (B), and additive components within a range that does not impair the effects of the present invention.

When using modified vegetable oil as the biomass plasticizer (B) contained in the styrenic resin composition of this embodiment, the content of the hydroxyl group-containing compound is It is preferably less than 3% by mass, more preferably less than 1% by mass. The hydroxyl group-containing compound of this embodiment refers to a compound having a hydroxyl group in a polymer, such as (meth)acrylic acid, maleic acid, and phthalic acid. If the hydroxyl group-containing compound exceeds 3% by mass, it will react with the modified vegetable oil and cause gelation, which will have the adverse effect of reducing moldability or deteriorating the appearance of the injection molded product. When using natural vegetable oil as the biomass plasticizer contained in the styrenic resin composition, the amount of the hydroxyl group-containing compound is not specified.

"Physical properties of styrenic resin compositions"
Preferred physical properties of the styrenic resin composition according to this embodiment will be explained below.

<Melt viscosity>
The melt viscosity (shear viscosity) of the styrenic resin composition of the present embodiment was measured using a twin capillary rheometer, Model RH10, manufactured by Malvern Instruments, at a resin temperature of 180°C and a shear rate of 1000 (1/s). (Pa・sec) or less, more preferably 130 (Pa・sec) or less, even more preferably 120 (Pa・sec) or less, even more preferably 115 (Pa・sec) or less, even more preferably 110 (Pa・sec) or less.・sec) or less, even more preferably 105 (Pa・sec) or less, even more preferably 100 (Pa・sec) or less, even more preferably 95 (Pa・sec) or less, even more preferably 90 (Pa・sec) or less ) or less, still more preferably 85 (Pa·sec) or less, even more preferably 80 (Pa·sec), even more preferably 75 (Pa·sec) or less.
When the melt viscosity measured at a resin temperature of 180° C. and a shear rate of 1000 (1/s) is 140 (Pa·sec) or less, molding becomes easy even at low temperatures, especially in injection molding.
Further, the melt viscosity (shear viscosity) measured at a resin temperature of 180°C and a shear rate of 40 (1/s) is preferably 1200 (Pa・sec) or less, more preferably 1100 (Pa・sec) or less, and even more preferably 1000 (Pa sec) or less, even more preferably 950 (Pa sec) or less, even more preferably 900 (Pa sec) or less, even more preferably 850 (Pa sec) or less, even more preferably 800 ( (Pa・sec) or less, even more preferably 750 (Pa・sec) or less, even more preferably 700 (Pa・sec) or less, even more preferably 650 (Pa・sec), even more preferably 600 (Pa・sec) ) is below.
When the melt viscosity measured at a resin temperature of 180° C. and a shear rate of 40 (1/s) is 1200 (Pa·sec) or less, it is effective to facilitate molding even at low temperatures, especially in sheet molding.
In addition, as the content of the biomass plasticizer (B) in the styrenic resin composition of the present embodiment increases, there is a tendency to show an effect of lowering the melt viscosity of the entire styrenic resin composition. However, if the compatibility with the styrene resin (A) and the biomass plasticizer (B) is low, that is, if the SP values of the styrene resin (A) and the biomass plasticizer (B) are not within the specified range, the styrene It is difficult to simply increase the content of the biomass plasticizer (B) in the styrenic resin composition because problems such as bleed-out are likely to occur during the production of the resin composition or the production of molded products from the composition. I found out that it becomes As a result, if the SP values of the styrenic resin (A) and the biomass plasticizer (B) are not within the specified range, it becomes difficult to lower the melt viscosity of the styrenic resin composition to the above range.

<Vicat softening temperature>
The Vicat softening temperature of the styrenic resin composition of this embodiment is preferably 30°C to 65°C, more preferably 31°C to 60°C, more preferably 32°C to 58°C, and even more preferably 33°C to The temperature is 56°C, more preferably 34°C to 55°C, even more preferably 35°C to 54°C. If the Vicat softening temperature of the styrenic resin composition is higher than 60° C., the fluidity decreases, making it difficult to mold the composition by significantly lowering the molding temperature. Furthermore, when the Vicat softening temperature of the styrene resin composition becomes low, the molded product tends to shrink and deform easily due to heat.
Note that the Vicat softening temperatures (° C.) in the present disclosure were all measured under a load of 49N in accordance with ISO 306.

<Swelling index>
In this embodiment, the swelling index of the styrenic resin composition containing the rubbery polymer particles (a-2) is preferably 8.5 to 14 from the viewpoint of impact strength, more preferably 9.0. ~13. In another embodiment, the rubbery polymer particles (a-2) of the present invention preferably have a swelling index of 7.0 to 14, more preferably 7.5 to 13. 5, more preferably 8.0 to 13. The swelling index is an index representing the degree of crosslinking of rubber particles. By setting the swelling index within the above range, the styrenic resin composition of the present invention has excellent impact properties. Note that in the present disclosure, the swelling index of the styrenic resin composition is a value calculated using the method described in the Examples section.

[Best mode]
A particularly preferred form of the styrenic resin composition of the present embodiment is a rubber-modified styrenic resin containing a polymer matrix phase containing the styrenic resin (A) and a rubber-like polymer dispersed in the polymer matrix phase. % by mass and more than 20% by mass to 50% by mass of a biomass plasticizer (B) with a biomass carbon ratio (pMC%) of 10% or more,
The content of (meth)acrylonitrile monomer units is 10% by mass or less based on the entire polymer matrix phase, and the SP value of the polymer matrix phase is 8.0 to 9.0,
The biomass plasticizer (B) has an SP value of 7.5 to 8.8,
A styrenic resin in which the difference in absolute value between the SP value of the polymer matrix phase and the SP value of the biomass plasticizer (B) is 0.8 or less, and the content of the halogen flame retardant is less than 1% by mass. It is a composition.
This makes it possible to provide a styrenic resin composition that reduces environmental impact by using biomass raw materials, has high mechanical strength during molding, and can be molded at low temperatures.
Note that the SP value of the polymer matrix phase may be the SP value of the styrenic polymer (a-1) constituting the polymer matrix phase. Additionally, the rubbery polymer may be rubbery polymer particles.

[Method for manufacturing styrenic resin composition]
The styrenic resin composition of this embodiment can be manufactured by adding each component directly to the polymerization step or devolatilization step as a polymerization raw material, or by melt-kneading each component by any method. . Examples include a method using a high-speed stirrer typified by a Henschel mixer, a batch kneader typified by a Banbury mixer, a single-screw or twin-screw continuous kneader, a roll mixer, etc., singly or in combination. The heating temperature during kneading is usually selected in the range of 120 to 250°C.

[Molded object]
The molded article of the present invention is characterized by containing the above-mentioned styrenic resin composition.
The styrenic resin composition of this embodiment can be produced by injection molding, injection compression molding, extrusion molding, or blow molding using the above-mentioned melt-kneading molding machine or using the obtained styrenic resin composition pellets as a raw material. The molded article can be manufactured by a method such as a molding method, a press molding method, a vacuum molding method, a foam molding method, or the like.

The molded article of this embodiment can be obtained by molding the styrenic resin composition of the above embodiment. The molded article of this embodiment is not particularly limited as long as it is obtained by molding the styrene resin composition according to the present invention, but it is preferable that the molded article has a portion with a thickness of 1 mm or less. The above styrene resin composition can be suitably used in a molded article having a portion with a thickness of 1 mm or less.
Moreover, the molded object of this embodiment may be a container or a sheet. The container of this embodiment may be directly manufactured (molded) from the styrene resin composition, or may be manufactured by further molding a sheet obtained by molding the styrenic resin composition. Moreover, the sheet of this embodiment can be used for manufacturing (molding) not only containers but also other molded objects.

The sheet of this embodiment is a non-foamed extruded sheet, and the thickness is not particularly limited, but can be, for example, 1.0 mm or less, and preferably 0.2 to 0.8 mm.
The sheet of this embodiment may be used in a multi-layered manner with a general styrene resin such as polystyrene resin, or in addition to or in place of the styrene resin layer, a layer other than the styrene resin may be used. It may be used in multiple layers with resin. Examples of resins other than styrene resins include PP resins, PP/PS resins, PET resins, and nylon resins.

"Injection molded product"
The present disclosure is an injection molded article containing the above styrenic resin composition. As a method for producing an injection molded article using the styrene resin composition of this embodiment as a raw material, a commonly known method can be used. The temperature of the molding machine is preferably 110°C to 250°C, more preferably 110°C to 230°C, even more preferably 110°C to 220°C, even more preferably 110°C to 200°C, even more preferably 110°C to 190°C. It is.
If the temperature of the molding machine is higher than 250°C, the styrene resin composition will thermally decompose, which is not preferable. On the other hand, if the temperature is lower than 110°C, the viscosity is so high that it cannot be molded, which is not preferable.
The styrene resin composition suitable for the injection molded article of the present embodiment contains 10 to 82.9% by mass of the styrenic polymer (a-1) and a biomass carbon ratio (pMC%) based on the entire styrene resin composition. ) contains 10% or more of a biomass plasticizer (B) from more than 15% by mass to 70% by mass,
It is preferable that the rubbery polymer particles are contained in an amount of 2 to 40% by mass of the entire styrene resin composition, and that the SP value of the biomass plasticizer (B) is 7.4 to 10.5.

Molded objects, especially injection molded objects (including injection compression molded objects), and sheet objects containing the styrene resin composition of the present embodiment can be used as food packaging containers, copying machines, fax machines, personal computers, printers, information terminals, refrigerators, and vacuum cleaners. It is suitably used for OA equipment such as microwave ovens, home appliances, housings and various parts of electric and electronic equipment, interior and exterior parts of automobiles, construction materials, foam insulation materials, insulation films, etc.

Hereinafter, embodiments of the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these Examples in any way.

"1. Measurement and evaluation method"
Measurement and evaluation of the physical properties of the styrenic resin compositions, extruded sheets, and injection molded products obtained in each Example and Comparative Example were performed based on the following methods.

(1) Styrenic resin (A) (including rubber-modified styrenic resin, styrenic polymer (a-1), and the like; the same applies hereinafter) used in Examples and Comparative Examples, biomass plasticizer (B), and styrene Measurement of Weight Average Molecular Weight of Resin Composition The weight average molecular weights of the styrene resin (A) and biomass plasticizer (B) were measured under the following conditions and procedures.
- Sample preparation: 5 mg of the 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: 2 SHODEX GPC KF-606M connected in series Guard column: SHODEX GPC KF-G 4A
Temperature: 40℃
Carrier: THF 0.50mL/min
Detector: RI, UV: 254nm
Calibration curve: To create the 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) were used to create the calibration curve. , F-2, F-1, A-5000). A calibration curve was created using a cubic linear approximation formula.

(2) Measurement of melt viscosity of resin composition The styrenic resin compositions used in Examples and Comparative Examples were measured at a resin temperature of 180°C and a shear rate of 40 (1 The melt viscosity was measured at 1/s) and 1000 (1/s).

(3) Measurement of Vicat softening temperature (°C) The Vicat softening temperature (°C) of the styrenic resin compositions used in the present examples and comparative examples was measured under a load of 49N in accordance with ISO 306.

(4) Measurement of content and swelling index of rubbery polymer particles (a-2) Content (mass%) of rubbery polymer particles (a-2) in rubber-modified styrenic resin or styrenic resin composition ), and the swelling index was measured as follows. Precisely weigh 1.00 g of the rubber-modified styrene resin or styrene resin composition into a sedimentation tube (this mass is referred to as W1), add 20 ml of toluene, shake at 23°C for 1 hour, and then use a centrifuge (Sakuma Seisakusho). The mixture was centrifuged for 60 minutes at a temperature of 4° C., a rotation speed of 20,000 rpm, and a centrifugal acceleration of 45,100×G using SS-2050A rotor: 6B-N6L (manufactured by Co., Ltd.). The precipitation tube was slowly tilted at about 45 degrees, and the supernatant liquid was removed by decantation. Accurately weigh the mass of insoluble matter containing toluene (this mass is designated as W2), then vacuum dry for 1 hour at 160°C and 3 kPa or less, cool to room temperature in a desiccator, and then weigh the toluene insoluble mass. was precisely weighed (this mass is designated as W3).
According to the following formula, the content and swelling index of the rubbery polymer particles (a-2) in the styrene resin (A) or the styrenic resin composition, that is, the content and swelling index of the rubbery polymer particles (a-2) in the styrenic resin (A) or the styrenic resin composition. The content and swelling index of the rubbery polymer particles (a-2) were determined.
Content of rubbery polymer particles (a-2) = W3/W1×100
Swelling index of rubbery polymer particles (a-2) = W2/W3

(5) Measurement of average particle size Measurement of the average particle size (μm) of the rubbery polymer particles (a-2) in the styrenic resin (A) or styrenic resin composition used in Examples and Comparative Examples , was measured using the following method.
Using COULTER MULTISIZER III (trade name) manufactured by Beckman Coulter Co., Ltd. equipped with an aperture tube with a diameter of 30 μm, 0.05 g of styrene resin (A) pellets or styrene resin composition pellets were placed in about 5 ml of dimethylformamide. It was left for about 2 to 5 minutes. Next, the dimethylformamide dissolved content was measured as an appropriate particle concentration, and the volume-based median diameter was determined.

(6) Measurement of rubber-like polymer content 0.25 g of the styrene resin (A) or styrene resin composition used in the examples and comparative examples was dissolved in 50 mL of chloroform, and iodine monochloride was added to form the rubber component. After the double bonds inside were reacted, potassium iodide was added to convert the remaining iodine monochloride to iodine, which was back titrated with sodium thiosulfate (iodine monochloride method). By this method, the mass of the rubber contained in the styrene resin (A) or the styrenic resin composition (this mass is referred to as W4) is measured, and this value and the styrene resin (A) or the styrene resin composition are measured. (this mass is designated as W1), the content (% by mass) of the rubbery polymer in the styrenic resin (A) or the styrene resin composition was determined by the following formula.
Content (mass%) of rubbery polymer in styrenic resin (A) or styrenic resin composition = W4/W1×100

(7) Measuring method of biomass carbon ratio (pMC%) The biomass carbon ratio (pMC%) of the biomass plasticizer (B) is determined by the following formula (1) using the radiocarbon ( ¹⁴ C) measurement method based on ASTM-D6866. ( ¹⁴ C plasticizer/ ¹² C plasticizer)/( ¹⁴ C standard material/ ¹² C standard material) was calculated by the AMS method using .
Formula (1):
Biomass carbon ratio (pMC%) = ( ¹⁴ C plasticizer / ¹² C plasticizer) / ( ¹⁴ C standard material / ¹² C standard material) × 100
In addition, oxalic acid (SRM4990) was used as a standard substance.
The biomass carbon ratio in the styrenic resin composition was also calculated in the same manner as above.

(8) Quantification of the content of biomass plasticizer (B) In the determination of the content of biomass plasticizer (B) in the styrenic resin compositions used in Examples and Comparative Examples, the following (8-1) or (8-2) Performed using either procedure. It should be noted that even when comparing the value obtained by the procedure (8-1) and the value obtained by the procedure (8-2), equivalent values were obtained.
(8-1) Analysis using NMR Vegetable oil (glycerin fatty acid ester) was dissolved in deuterated chloroform (containing 1% TMS) containing 2-dimethoxyethane as an internal standard substance, and ¹ H-NMR measurement was performed. Ta. If the TMS peak is taken as a standard of 0 ppm, there is a 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 a peak derived from 1,2-dimethoxymethane at δ 3.4 to 3.6 ppm. A peak is detected. The peak area derived from vegetable oil is calculated when the peak area derived from 1,2-dimethoxymethane is set to 1. By performing this operation while varying the concentration of vegetable oil, a calibration curve of vegetable oil concentration was created.
The pellet-shaped styrene-based resin composition obtained in the example or comparative example was dissolved in deuterated chloroform (containing 1% TMS), and ¹ H-NMR measurement was performed. Using the above calibration curve, styrene The vegetable oil content in the resin composition was quantified.
In the above method, if another peak overlaps with the peak of the internal standard substance and is difficult to quantify, an appropriate substance may be used as the internal standard substance as appropriate. Furthermore, vegetable oil can also be quantified by the triglyceride-derived peak detected at 5.0 to 5.5 ppm.
(8-2) Calculation from methanol soluble content 1.0 g of the pelleted styrene resin composition obtained in the example or comparative example (this weight is designated as W11) was placed in a 20 mL screw bottle, and methyl ethyl ketone 10 mL of was added. After completely dissolving the pellet using a shaker, 5 mL of methanol was added to precipitate the styrene polymer as an insoluble matter, and the insoluble matter was centrifuged by centrifugation at 2000G for 10 minutes using a centrifuge. Ta. Next, 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 volatilize the solvent. The mass of the insoluble matter after drying was measured, and this mass was designated as W12. Using the measured masses W11 and W12, the methanol soluble content (W13) was defined as follows.
Methanol soluble content (W13) = W11-W12.
In addition, in this operation, the supernatant liquid after centrifugal sedimentation was measured by GC-MS to determine the content of styrene oligomers, residual monomers, residual solvents, and other low-molecular substances other than methanol-soluble plasticizers. 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 styrenic resin composition was determined as follows.
Content of biomass plasticizer (B) = W13-W14

(9) Calculation of SP value The SP value of each material used in the Examples and Comparative Examples is the SP value using the Hilderbrand method (including the Hansen method), and the literature value (“Basics of Biomaterials” “Kazuhiko Ishizuka・Calculated by turbidity titration method with reference to "Takao Hanawa and Mizuo Maeda (eds.)" (Japan Medical Museum Publishing) or "J. Appl. Polym. Sci., 12, 2359 (1968)".
In addition, in the styrene resin compositions of Examples and Comparative Examples, since each component blended in the composition is known, the SP value can be easily calculated by the above method. On the other hand, if 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 steps (i) to (iv). Step (i): Add the target sample (styrenic polymer or plasticizer) recovered or separated from the styrenic resin composition to a solvent with a known SP value, and add the sample to the solvent with a known SP value. Perform a dissolution test to determine whether the substance has dissolved or not. Procedure (ii): Next, the SP values of the solvents subjected to the dissolution test in procedure (i) are three-dimensionally plotted. Step (iii): Perform steps (i) and (ii) using 15 to 20 different solvents. Step (iv): By calculating a sphere that includes the coordinates of the solvent in which the sample was dissolved but does not include the coordinates of the solvent in which the sample was not dissolved, the center coordinates of the sphere represent the Hansen SP value, and the distance from the origin is calculated. The solubility parameter using the Hildebrand method (including the Hansen method) is calculated by letting the distance represent the Hildebrand SP value.
The SP values calculated by the above steps (i) to (iv) are generally in agreement with the above literature values or the SP values calculated by turbidity titration.
In addition, visually confirm whether the sample is dissolved or insoluble in a solvent with a known SP value. Specifically, in the case of insolubility, when the sample is dissolved in the solvent, it becomes cloudy or becomes droplets, and the sample and the solvent are separated. On the other hand, in the case of dissolution, when the sample is dissolved in the solvent, it is mixed uniformly while remaining transparent.
Furthermore, if the biomass plasticizer (B) has a low molecular weight, it may not be possible to calculate it by turbidity titration. In that case, instead of the above turbidity measurement method, Fedors' estimation method or Hoy's calculation method is adopted (for example, see "Paint Research (Considerations on Solubility Parameters of Additives) No. 152 Oct. 2010") ).

(10) Tensile Nominal Strain at Break The styrenic resin compositions obtained in the Examples and Comparative Examples were injection molded at 220° C. according to JIS K 7152, and the nominal tensile strain at break was measured according to JIS K 7161.

(11) Minimum temperature at which 2 mm thick plate can be formed The styrenic resin compositions obtained in the Examples and Comparative Examples were molded using an injection molding machine EC60N manufactured by Toshiba Machine Co., Ltd. at a mold temperature of 45°C and an injection pressure of 40 MPa. When a 2 mm plate was molded, the lowest temperature at which a molded product could be obtained without short shots was measured.
The lower the minimum moldable temperature, the more difficult it is for the molded product to yellow. In addition, at lower temperatures, volatile components are less likely to come out from the resin, making mold stains less likely to occur.

(12) Number of mold fouling occurrences After the styrene resin compositions obtained in Examples and Comparative Examples were continuously molded into 2 mm thick plates at the lowest moldable temperature shown in (11), deposits were observed on the mold. Mold contamination was evaluated using the number of shots until the mold was removed as an index. If the number of shots until mold deposits were confirmed was less than 100, the frequency of mold cleaning would increase and productivity would drop, so 100 or more shots were considered acceptable.

(13) Heat shrinkage rate The styrenic resin compositions obtained in the Examples and Comparative Examples were molded using an injection molding machine EC60N manufactured by Toshiba Machine Co., Ltd. at the minimum moldable temperature shown in (11), in accordance with ISO 3167. A dumbbell test piece was prepared, and the molding shrinkage rate after being left at 50°C for 1 hour was measured. The molding shrinkage rate is determined by L1, which is the length of the dumbbell test piece that has been conditioned at 23°C for 12 hours or more after molding, and the length of the dumbbell test piece after the conditioned dumbbell test piece is left at 50°C for 30 minutes. When L2 is defined as (molding shrinkage rate)=(L1-L2)/L1. 0.1% or less was considered to be a pass.

(14) ΔYI after staying in the molding machine for 30 minutes
The YI value of a molded article molded after allowing the styrenic resin compositions obtained in Examples and Comparative Examples to remain in the molding machine cylinder for 30 minutes at the minimum moldable temperature shown in (11), and the YI value of the molded product without residence. The difference in YI value of molded products was measured.

(14) Minimum temperature at which sheet formation is possible When a sheet with a thickness of 0.3 mm was produced using a 25 mmφ single-screw sheet extruder manufactured by Sokensha at a screw rotation speed of 80 rpm, no overtorque or vent-up occurred at the screw part. The lowest molding temperature at which sheet molding was possible was measured.
The lower the minimum moldable temperature, the less dirt (dirt) that forms on the sheet molded product and the better the sheet appearance.

(15) Sheet tensile nominal strain at break The sheet tensile nominal strain at break of the extruded sheets produced in Examples 1 to 11 and Comparative Examples 1 to 4 was measured. Specifically, JIS K6251-3 dumbbells were punched out from the extrusion (MD) direction of the extruded sheet, and a tensile test was conducted at a test speed of 50 mm/min and a distance between grips of 60 mm, and the tensile breakage Strain was measured. Ta

(16) Evaluation of sheet appearance (number of stains) When producing the extruded sheets obtained in Examples and Comparative Examples, the sheet surface was visually confirmed and the number of stains with a major axis of 1.0 mm or more per 10 m was measured. .

"2. Raw materials"
The materials used in Examples and Comparative Examples are as follows.
[Styrenic resin (A)]
- As the styrene resin (A), a rubber-modified styrenic resin (1) obtained by the following manufacturing method was used.
(Production method of rubber modified styrenic resin (1))
84.8% by mass of styrene, 8.0% by mass of ethylbenzene, 7.0% by mass of polybutadiene rubber (BR15HB manufactured by UBE Elastomer Co., Ltd.), and 0.2% of liquid paraffin product name "PS350S" (manufactured by Sanko Chemical Industry Co., Ltd.) The mixed and dissolved polymer solution was continuously charged at 3.24 liters/hour into a 6.2-liter laminar flow reactor-1 equipped with a stirrer and capable of temperature control in three zones, and the temperature was adjusted to 123℃/128℃. The temperature was adjusted to 132°C/132°C. The rotation speed of the stirrer was 70 revolutions per minute. The reaction rate at the reactor outlet was 33%.
Subsequently, the reaction solution was sent to a 6.2 liter laminar flow reactor-2 which was connected in series with the laminar flow reactor-1 and was equipped with a stirrer and whose temperature could be controlled in three zones. The stirring speed of the stirrer was 40 revolutions per minute, and the temperature was set at 141°C/146°C/151°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 revolutions per minute, and the temperature was set at 156°C/160°C/165°C.
The polymer solution continuously discharged from the polymerization reactor (laminar flow reactor-3) is heated to 230°C in an extruder with a vacuum vent, and is devolatilized under a reduced pressure of 0.8 kPa, then pelletized and pelletized. A rubber-modified styrenic resin (1) was prepared.
- As the styrene resin (A), a rubber-modified styrenic resin (2) obtained by the following manufacturing method was used.
(Production method of rubber modified styrenic resin (2))
A polymerization solution containing 88.7% by mass of styrene, 6.5% by mass of ethylbenzene, and 4.8% by mass of polybutadiene rubber (Diene 55 manufactured by Asahi Kasei Chemicals) was mixed and dissolved in a polymer solution containing 88.7% by mass of styrene, 6.5% by mass of ethylbenzene, and 4.8% by mass of polybutadiene rubber. The mixture was continuously charged into a 2 liter laminar flow reactor-1 at a rate of 3.24 liters/hour, and the temperature was adjusted to 125°C/130°C/135°C. The rotation speed of the stirrer was 70 revolutions per minute. The reaction rate at the reactor outlet was 30%.
Subsequently, the reaction solution was sent to a 6.2 liter laminar flow reactor-2 which was connected in series with the laminar flow reactor-1 and was equipped with a stirrer and whose temperature could be controlled in three zones. The stirring speed of the stirrer was 40 revolutions per minute, and the temperature was set at 139°C/142°C/145°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 revolutions per minute, and the temperature was set at 144°C/151°C/152°C.
The polymer solution continuously discharged from the polymerization reactor (laminar flow reactor-3) is heated to 230°C in an extruder with a vacuum vent, and is devolatilized under a reduced pressure of 0.8 kPa, then pelletized and pelletized. A rubber-modified styrenic resin (2) was prepared.
(butadiene rubber)
・Polybutadiene rubber (Diene 55 manufactured by Asahi Kasei Chemicals), polybutadiene rubber UBEPOL BR (BR15HB manufactured by UBE Elastomer Co., Ltd.)
[Biomass plasticizer (B)]
(modified 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 (Hansen method) Distance from the origin in three-component coordinates of dispersion force term (δD), polarity term (δP), and hydrogen bond term (δH)): 9.0 ((cal/cm ³ ) ^1/2 ) , Epoxy modification rate: 5 mmol per 1 g
(natural vegetable oil)
・Palm oil (product name "Multi Ace 20 (S)" (Nissin Oilio Group Co., Ltd.), weight average molecular weight (Mw = 1000), biomass carbon ratio (pMC%) 100%, melting point: 22 ° C, SP value ( This is a calculated value using the Hansen method, and the distance from the origin in three-component coordinates of the dispersion force term (δD), polarity term (δP), and hydrogen bond term (δH)): 8.2 ((cal/cm ³ ) ^{1/ 2} ))
・Soybean oil (product name: "Soybean White Squeeze Oil (S)" (Nissin Oilio Group Co., Ltd.) Weight average molecular weight (Mw = 1000), Biomass carbon ratio (pMC%) 100%, Melting point -8℃, SP value ( This is a calculated value using the Hansen method, and the distance from the origin in three-component coordinates of the dispersion force term (δD), polarity term (δP), and hydrogen bond term (δH)): 8.2 ((cal/cm ³ ) ^{1/ 2} ))

[others]
(liquid paraffin)
・Liquid paraffin, product name "PS350S" (manufactured by Sanko Kagaku Kogyo 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

"3. Examples and comparative examples"
[Examples 1 to 6, Comparative Examples 1 to 2]
(Production method of styrenic resin compositions (PS-1) to (PS-6), (PS-12), (PS-13))
The styrenic resin composition (PS-1) is produced by melting the rubber-modified styrenic resin (1) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, palm oil was added to the rubber-modified styrenic resin (1) so that the palm oil content was 17% by mass, and the mixture was melt-kneaded and produced. The cylinder temperature after adding palm oil was 190°C. Styrenic resin compositions (PS-2) to (PS-6), (PS-12), and (PS-13) are the same as styrene resin composition (PS-1) except for the amount of palm oil added. , rubber-modified styrenic resin (1) was melted and kneaded at 220° C., and then palm oil was added thereto. Table 2 shows the amount of palm oil added, the cylinder temperature after addition, and whether production is possible (producible ○, production not possible x). Regarding the obtained styrene resin compositions (PS-1) to (PS-6), (PS-12), and (PS-13), the physical properties of the styrene resin compositions shown in Table 3 were determined according to the above "1. Measurement was performed using the method described in the section "Measurement and Evaluation Methods".

[Example 7]
(Production method of styrenic resin composition (PS-7))
The styrenic resin composition (PS-7) is produced by melting the rubber-modified styrene resin (2) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, palm oil was added so that the rubber-modified styrenic resin (2) contained 30% by mass of palm oil, and the mixture was melt-kneaded and produced. The cylinder temperature after adding palm oil was 170°C. In addition, Table 2 shows whether or not it is possible to produce (producible 〇, producible not ×). Regarding the obtained styrenic resin composition (PS-7), the physical properties of the styrenic resin composition shown in Table 3 were measured by the method described in the above "1. Measurement and evaluation method" column.

[Example 8]
(Production method of styrenic resin composition (PS-8))
The styrenic resin composition (PS-8) is produced by melting the rubber-modified styrenic resin (1) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, soybean oil was added to the rubber-modified styrenic resin (1) so that the soybean oil contained in an amount of 30% by mass, and melt-kneaded to produce the resin. The cylinder temperature after adding soybean oil was 170°C. In addition, Table 2 shows whether or not it is possible to produce (producible 〇, producible not ×). Regarding the obtained styrenic resin composition (PS-8), the physical properties of the styrenic resin composition shown in Table 3 were measured by the method described in the above "1. Measurement and evaluation method" column.

[Example 9, Comparative Example 3]
(Production method of styrenic resin composition (PS-9), (PS-14))
The styrenic resin composition (PS-9) is produced by melting the rubber-modified styrenic resin (1) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, epoxidized soybean oil was added to the rubber-modified styrenic resin (1) so that the epoxidized soybean oil contained 16% by mass, and the mixture was melt-kneaded. The cylinder temperature after adding the epoxidized soybean oil was 190°C. Styrenic resin composition (PS-14) is made by melt-kneading rubber-modified styrene resin (1) at 220°C in the same manner as styrene resin composition (PS-9) except for the amount of epoxidized soybean oil added. After that, epoxidized soybean oil was added to produce the product. Table 2 shows the amount of epoxidized soybean oil added, the cylinder temperature after addition, and whether production is possible (producible ○, production not possible ×). The physical properties of the obtained styrenic resin compositions (PS-9) and (PS-14) shown in Table 3 were measured by the method described in the above "1. Measurement and evaluation method" column. It was measured.

[Example 10]
The styrenic resin composition (PS-10) is produced by melting the rubber-modified styrenic resin (1) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, palm oil and liquid paraffin are added so that the rubber-modified styrenic resin (1) contains 16% by mass of palm oil and 4% by mass of liquid paraffin, and is melt-kneaded. Manufactured. The cylinder temperature after adding palm oil was 185°C. In addition, Table 2 shows whether or not it is possible to produce (producible 〇, producible not ×). Regarding the obtained styrenic resin composition (PS-10), the physical properties of the styrenic resin composition shown in Table 3 were measured by the method described in the above "1. Measurement and evaluation method" column.

[Example 11]
The styrenic resin composition (PS-11) is produced by melting the rubber-modified styrene resin (1) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, palm oil and liquid paraffin are added so that the rubber-modified styrenic resin (1) contains 12% by mass of palm oil and 5% by mass of liquid paraffin, and is melt-kneaded. Manufactured. The cylinder temperature after adding palm oil was 190°C. In addition, Table 2 shows whether production is possible (producible 〇, production not possible ×). Regarding the obtained styrenic resin composition (PS-11), the physical properties of the styrenic resin composition shown in Table 3 were measured by the method described in the above "1. Measurement and evaluation method" column.

[Comparative example 4]
(Production method of styrenic resin composition (PS-15))
The styrenic resin composition (PS-15) was prepared by mixing 80% by mass of the rubber-modified styrenic resin (1) and 20% by mass of polylactic acid using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machine Co., Ltd.). ) was melted and kneaded at a cylinder temperature of 220°C. In addition, Table 2 shows whether or not it is possible to produce (producible 〇, producible not ×). Regarding the obtained styrenic resin composition (PS-15), the physical properties of the styrenic resin composition shown in Table 3 were measured by the method described in the above "1. Measurement and evaluation method" column.

[Comparative example 5]
(Production method of styrenic resin composition (PS-16))
The styrenic resin composition (PS-16) is produced by melting the rubber-modified styrene resin (1) using a twin-screw kneading extruder (TEM-26SS-12 manufactured by Toshiba Machinery Co., Ltd.) at a cylinder temperature of 220°C. After kneading, liquid paraffin was added to the rubber-modified styrenic resin (1) so that the liquid paraffin contained 17% by mass, and the liquid paraffin was melted and kneaded. It was judged that production was impossible because of poor compatibility and significant bleed-out. The cylinder temperature after liquid paraffin was added was 190°C.

Claims (10)

30 to 84.9% by mass of a styrenic resin (A) containing a styrenic monomer unit;
A styrenic resin composition containing a biomass plasticizer (B) having a biomass carbon ratio (pMC%) of 10% or more and more than 15% by mass and not more than 70% by mass. The styrenic resin composition according to claim 1, having a Vicat softening temperature of 65°C or less. The styrenic resin composition according to claim 1 or 2, having a melt viscosity of 140 (Pa·sec) or less when measured at a resin temperature of 180° C. and a shear rate of 1000/sec. The styrenic resin composition according to claim 1 or 2, having a melt viscosity of 1200 (Pa·sec) or less when measured at a resin temperature of 180° C. and a shear rate of 40/sec. The styrenic resin (A) is a rubber containing a polymer matrix phase composed of the styrenic polymer (a-1) containing the styrenic monomer unit and rubber-like polymer particles (a-2). It is a modified styrene resin,
Claim: The absolute value of the difference between the SP value of the styrenic polymer (a-1) and the SP value of the biomass plasticizer (B) is less than 2.5 (cal/cm ³ ) ^1/2 . 2. The styrenic resin composition according to 1 or 2. The styrenic resin composition according to claim 1, wherein the biomass plasticizer (B) has an SP value of 7.4 to 10.5 (cal/cm ³ ) ^1/2 . The styrenic resin (A) is a rubber containing a polymer matrix phase composed of the styrenic polymer (a-1) containing the styrenic monomer unit and rubber-like polymer particles (a-2). It is a modified styrene resin,
and the content of the rubbery polymer particles (a-2) is 2 to 40% by mass with respect to the total amount (100% by mass) of the styrene resin (A), and the content of the rubbery polymer particles (a- The styrenic resin composition according to claim 1 or 2, wherein the average particle diameter of 2) is 0.3 to 7.0 μm. 1 or 2, wherein the content of the styrenic monomer units contained in the styrenic resin (A) is 50% by mass or more with respect to the total amount (100% by mass) of the styrenic resin (A). 2. The styrenic resin composition according to any one of 2. An injection molded article obtained by injection molding the styrenic resin composition according to claim 1 or 2. A sheet comprising the styrenic resin composition according to claim 1 or 2.